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October 1975 35p
AND BROADCAST ENGINEERING
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FkzÚiúy Performarce Reliability Advanced
teo-nckozy -io'reoordinganÚbroadcas ng.
At[o|to work o!vvaym for you -never against
you. The result io uncommon yciatinguioheÓ.
Cadac offer system design flexibilit to it
your need w thin a reistic cost lo a realistic:
ivery date or time.
Before de:icinç, why not talk to :ieop whose
years of decication ard involverent ii al
aspects o'a:wdio technology ia real and
practical.
Wart the fijI story? Phone, vinte or telex:
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dHarperdmn Hers. AL5 5EL
7) 64351 -elex 826323
ztcv,xhouse
Ro Jr(
m:Studio
studio sound
AND BROADCAST ENGINEERING
EDITOR MICHAEL THORNE
ASSISTANT EDITOR FRANK OGDEN
EDITORIAL PRODUCTION DRUSILLA DALRYMPLE
EXECUTIVE ADVERTISEMENT MANAGER
DOUGLAS G. SHUARD
ADVERTISEMENT MANAGER TONY NEWMAN
MAGAZINE SALES MANAGER DON BAILEY
OCTOBER 1975 VOLUME
ITHE LINK HOUSE GROUP
Editorial and Advertising Offices: LINK HOUSE, DINGWALL
AVENUE, CROYDON CR9 2TA.
Telephone:
01
-686 2599
Telex: 947709, EXCHMART CROYDON
Telegrams: Aviculture Croydon
©
Link House
Publications Ltd 1975. All rights reserved.
CONTENTS
FEATURES
SURVEY: AUDIO MIXERS
PROGRAMMABLE MIXING
By Paul C. Buff
OLD IDEA-NEW TWIST
By Carl J. Yanchar and Kent Duncan
COMPUTER ASSISTED MIXING
By Derek Tils ey
62
82
86
88
COLUMNS
NEWS
LETTERS
28
PATENTS
36
WORK
AGONY
38
32
55, 87
REVIEWS
17
NUMBER 10
1
Whether you prefer your automation hot, cold or with two
sugars, you'll probably agree that there is something to be gained.
The remaining discussion centres on how far and, to some
extent, how. But the mechanics are relevant only in a specific
studio environment. Once more than one becomes involved, the
compatibility problem appears, if modestly at present.
The control of the remix levels represents another insert point
between the tape machine and what finally comes at you through
the monitors. There are similarities with the noise reduction
problem, except that we are dealing with a control function
rather than the signal itself.
So what do we find? The tape code is variable, its position on
tape has alternatives and likely to have more with imminent
introductions, and the sampling rate is variable. The coming
MCI system, with a slave data tape, and the MCI /3M combination
using 76 cm tape, also represents a clear, logical way of doing
things, but again is in its turn a further break with convention
and a consequent weakening of compatible data links. This
example is not unusual in its breaks with the past, which are
justified by making appropriate use of available resources and
technology, but is the most recent.
And so much for the problem. It would be unfortunate if it
hindered widespread use, for automation has largely won over
the initial antipathy. Perhaps compatibility is overstated: there
is little need for breaking in the middle of a mix -not studios, at
least. But there are strong arguments for retaining the work
which went into the mix's creation in some form, so that when
backing track extracts, single mono -compatible remixes and quad
stereo-compatible remixes are tackled some months later there is
a reference start somewhat better than the original master mix
full stop. One suspects the decision has effectively been made:
automated mixing is so young as not to have seen much change
in its surroundings, so we cannot really evaluate those objections
now.
We'll know more in a couple of years' time. Let's hope the
decision was the right one.
KNICK PEAK PROGRAMME METER AD26V
By
Hugh Ford
42
REVOX A700
and Angus McKenzie
SOUNDCRAFT 12/4
By Angus McKenzie and Tony Faulkner
ALLEN & HEATH 16/8
By Angus McKenzie and Tony Faulkner
By Hugh Ford
48
86
90
DISTRIBUTION
STUDIO SOUND, published monthly, enables engineers and studio
management to keep abreast of new technical and commercial developments
in electronic communication. It is available without charge to qualified
readers; these being directors, managers, executives and key personnel
actively engaged in the sound recording, broadcasting and cinematograph
industries in any part of the world. Non -qualifying readers can buy
STUDIO SOUND at an annual subscription of £5.80 (UK) or £6.00 overseas.
STUDIO SOUND is published on the 14th of the preceding month
un less that date falls on a Sunday, when it appears on the Saturday.
CORRESPONDENCE AND ARTICLES
All STUDIO SOUND correspondence should
be sent to the address
printed on this page. Technical queries should be concise and must
include a stamped addressed envelope. Matters relating to more than one
department should occupy separate sheets of paper or delay will occur
in replying
BINDERS
Loose -leaf binde.s for annual volumes of STUDIO SOUND are
available from Modern Bookbinders, Chadwick Street, Blackburn, Lancashire.
Price is £1.50 (UK and overseas). Please quote the volume number or
date when ordering.
Total average net circulation of 8535 per issue
1974. UK 5663, overseas 2872.
during
IA.B.
.,K. Of ,,,,":;
OF 71111
J
ITA-Europe's Leading Distributor
4Channel
Channel
TEAC A3340 (S) RECORDER
Industrial version upgraded to studio requirements, with increased
signal to noise performance and improveo reliability. Four totally
independent channels each with sel sync. input mixing, switchable
VUs and all the facilities for easy multitrack'ing. This industrial model
is in more studios than any other version.
Available only from ITA. (Semi -pro version also available.)
price
Immediate delivery
Breakthrough
ITAM 805 MASTER RECORDER
lin.rration ITAM technology brings
you the studio equipment you need at a truly realistic cost.
At a time of unprecedented
OTARI MX -7000 MASTER RECORDER
A field- proven master recorder from Japan's biggest manufacturer of
professional tape recorders and duplicating equipment. Features
include 3 -speed operation, rugged construction, front panel EQ on
record, play and bias, FET inputs, plug -in head assembly.
Track configurations: Mono, Stereo, 3- channel (NAB cartridge
compatible), 4- channel or ,'- inch, 8- channel one inch.
Quick delivery.
Prices approx. 60% of comparable products.
207-Lowest
Fully modular electronics using plug -in PCBs throughout. Separate
sync and replay amps give ideniicall levels. Switchable VUs with
slow decay. Individual oscillator for each channel, Dolby A switching
facility. Comprehensive facilities include sync on all channels servo
controlled capstan, modular electronics, variable speed (optional
relay -solenoid operation. Compact console presentation for easy
portabi ity.
£1790 + VAT
I
Prices
Full console optional extra.
Finance available
of Multitrack Equipment
Channel
New Products
LYREC 2"
track 2' recorder is one of the finest examples of
multitrack recorders currently available from Europe. Price will be
about £8,990 H- VAT. 24 Track £12,885 H- VAT.
The Lyrec
16
NHGJEIll
ITA
10 -4
Ten balanced inputs, four output groups, 4 limiters, bass mid and
treble EQ, modular construction, headphone monitoring. Extremely
high quality construction only matched by mixers costing around
£ 1000. £647 + VAT.
Twenty input version £990 + VAT.
Eight output version £1260 + VAT.
Full capability professional machine.
Front panel edit mode and cue facilities
Motion sensing
Sync and normal replay level identical.
600 ohm, XLR + 4 dB output.
Additional 4 track replay head.
Two and four channel versions.
Test and cue oscillator.
Edital editing block
72,.
15
ips
Balanced input and
Immediate delivery
Also available for hire
industrial Tape Applications
MX -5050
output options.
£440 + VAT
A
Pratt Street, London NW1 OAE.
Tel: 01 -485 61 62 Telex: 21879
5
RELIABILITY
PERFORMANCE
IT HAS TO BE
AMCRON
!
Amcron power amplifiers come in three sizes, D60, D150 and DC300A, and all offer superb
quality sound reproduction combined with a well- earned reputation for reliability. Introduced
back in 1967, they are found in all possible applications involving amplification of Audio
Frequency signals. Little wonder that they are chosen by leading studios such as Advision,
De Lane Lea, Island, The Manor, Central Sound, and Kingsway Recorders to name but a few.
2NL INDUSTRIAL ESTATE,
MACINNES LABORATORIES LTD.
SAXMUNDHAM, SU FOLKTPN7
TEL: (0728) 2262 2615
THE NEW NAGRA IS MODEL
(7.5 ips) or twin
speeds (7.5 & 3.75 ips)
Single
Designed for the
sound recordist on
Separate easily
detachable battery
location
Light weight - 8Ib 3oz
(exc batteries and tape)
3 motor tape transport
Fast winding and
rewinding
compartment
Push button controls
o
copy of the Brochure on the NAGRA
I of the other well known NAGRA models.
NACRA
Name
P lease
send me
a
I
Address
IS
I
and details
KUDELSKI
HAYDEN
I Hayden Laboratories Ltd, Hayden House, 17 Chesham Road,
Telephone 02403 5511
Amersham, Buckinghamshire
6
STUDIO SOUND, OCTOBER
1975
I 1
Ss 1o7
J
Optional (internal)
extras:
Pi lotton facility
Automatic level
control
Reference generator
Crystal generator
3 different meter
characteristics
Five monitors. One sound. Five JBL studio monitors.
You could record with any one, play back on any other,
and take your pick among the rest for mixing or mastering
The only differences are acoustic output, size and cost.
No matter what size your studio is, you can cross reference with any other studio using JBL's.
But readin isn't knowing for sure. Come listen to
one. Or two Or five.
C.E.Hammond Er Co Ltd
Lamb House ChJrch Street London W4 2PB
Tel 01- 9954551
JBL
Series 2 now available:
Electronic
Delay System EMT 440
Product Line
with digital delay network
Reverberation Devices
Studio Turntables and
Pick -up Cartridges
Tape Recorders with endless
loop cassettes, and for 24 hour
recordings
Electronic Delay Systems
Compressor -Amplifiers
Microphone Winch Systems
Electronic Tuning Forks and
Polarity Testers
Flutter Analyzers
. Detailed Information
furnished on request
A U D
I
O
TECHNOLOGY
EMT- FRANZ mbH.
P.O.B.
1520
D
"willaraft
/1111111M,
-7830 LAHR -1
modern audio frequency delay unit, which converts an analogue signal at first
into multi -stage digital information. With a certain delay, this signal is sent through
a multiple storage network of integrated shift registers and subsequently
converted back into an analogue output signal. The advantages of this system
compared to conventional tape delay machines lie in its fully electronic
construction without moving parts. This therefore, results in wear free operation
with no wow and flutter and considerably lower noise and distortion figures.
A
Telex 754319
r
I WANDERED LONELY AS
Build a mixer to your own
A..1.
specification using our
easy to wire
poor, harassed, misunderstood, dejected PA man,
unable to locate the righr gear at the right price
in the right time, unaware of Mustang's versatile
new modular range:
AUDIO
MODULES
MM series mixers
MMA series integrated mixer amplifiers
A series slave amplifiers
8
For more details contact
new units in 32 variations not counting
input combinations. 7 to 10 days current
availability, and realistically priced.
Request brochure IB for the full
specifications or ask for our full catalogue.
Richard Brown at Zero 88
Mixers, mixer amplifiers and slaves, power
amplifiers, lighting controls, transformers and
cabinets.
MUSTANG
COMMUNICATIONS
Nelson Street, Scarborough,
North Yorkshire Y012 7SZ
England
Telephone 0723-63298
L
8
STUDIO SOUND, OCTOBER
1975
A
Prices from £2.75 excl.VAT
Zero 88 Lighting Limited
115
Hatfield Road, St. Albans, Herts.
Tel: St. Albans (0727) 63727
Orban Parasound's
Two Channel Parametric Equaliser
At less than £400 U.K. List, it's the most cost-effective professional
equaliser available today.
Two totally independent channels each with four overlapping
4.3 octave range bands.
Continuously variable tuning, equalisation level and bandwidth
controls on each band.
Up to 16 db boost, minus infinity cut available on each band.
`Constant Q' rather than reciprocal equalisation curves.
Extremes of equalisation are musically useful instead of being
peaky and ringy.
Click -free in /out switching.
L.E.D. overload indication.
For full information or a demonstration of the 621 B equaliser,
the 516 EC dynamic sibilance controller or any other Orban product contact:
Scenic Sounds Equipment,
27 -31 Bryanston Street,
London W1H 7AB.
Phone No. 01 -935 0141.
Orban /Parasound Inc.,
San Francisco, California 94109
9
REWAUDIOCiiNT'CTS
r.,,
LONDON'S LEADING CONSULTANTS AND DISTRIBUTORS
FOR P.A., STUDIO AND PROFESSIONAL AUDIO EQUIPMENT
.0.
4
4
l'EA(,'
CHANNEL
PRICE
-
BREAKTHROUGH!
New Dokorder 8140
11ILulu!(
Multi-Sync Recorder
REVOX A77 Mk IV
NEW TEAC
3340S
The world famous A77 1102 Series II semiprofessional recorder, available in 3,a- and 71
i.p.s. or 7; and 15 i.p.s. speeds±sel -sync and
varipatch conversions. This machine proves a
long standing favourite with the REW Audio
Contracts range of mini -studios. In stock.
INDUSTRIAL
The Teac A 3340S professional model is a very
high quality, 4 track (separate) recorder.
Operating at 7+ and 15 i.p.s. with full built -in
Potential 8 input source (4
sel -sync facility.
line and 4 mic) incorporating separate mixing
controls on front panel. In stock.
NETT PROFESSIONAL PRICE ON APPLICATION
NETT PROFESSIONAL PRICE ON APPLICATION
MICROPHONES
REW Audio Contracts are able to offer the
following microphones at professional prices
(subject to stock), to bona -fide pro users.
AKG
SHURE
CALREC
BEYER
RESLO
SONY
ELECTROVOICE
DAN GIBSON
SENNHEISER
SNS
Radio Microphone
Phone for a fantastic quotation!
UBL
Similar facilities to Teac 3340. Three motors,
3 heads, solenoid operation, electronic echo.
Speeds 72 and 3,a- i.p.s., 7in. spools. Mic and
linemixing.
Nett Professional Price L329
-¡-
VAT.
also available Model 7140. Details on request.
REW are pleased to announce their
as the only London Distributors for JBL Professional Products.
appointment
Special prices for Studios and O.E.M. users.
A re- coning service will be available shortly.
BRITAIN'S WIDEST RANGE OF MIXERS
SPECIAL OFFER
FAMOUS MIXER
This high quality inexpensive 4/2
mixer incorporating 3 band eq,
pan pots, faders, limiters and
echo send controls make it a
,good starting point for the basic
'mini studio set up.
R.R.P. E139
-;-
VAT
REW Nett Pro Price
£99 -F VAT
All models ex stock
SOUNDCRAFT 12/4
Just arrived -12/4 Recording Con-
sole which is built into
a
teak case,
incorporating 12 input and 4 output
channels, output limiters, and full
monitoring facilities. All input and
output connectors are Switchcraft
(XLR equiv.) except line input
which are } jack. 200 ohm mic.
inputs are balanced. 4 band E.Q.;
f/b send; echo send; pfl; channel
switch; pan pots and faders.
NETT PROFESSIONAL
E975 -r- VAT
PRICE
Power supply extra
ALLEN & HEATH POP MIXER 16/2. ALLEN & HEATH MINI MIXER 6/2. ALLEN & HEATH MON MIX.
BOX 5/2. SOUNDCRAFT 12/4. SOUNDCRAFT 1612. ALICE AD62 6/2. AUDIO TECHNICS MM42 4/2.
SONY MXI6 8/4. LAMB PML422 4/2 (PROVISION FOR 8/4)
NEW TRADE PRICE LIST JUST OUT -SEND FOR YOUR FREE COPY NOW
REWAIÍI IiMras, 14G
Irujdms
Tel: 01 -240 306415
VIDEO, INDUSTRIAL AND STUDIOS AT
IWaüfonUaIS,N4Rl s,mllirswood,wmswati:o-540 908415 Ell aSsilli
10
STUDIO SOUND, OCTOBER
1975
LATEST MIXER PREAMP
FROM ICE
STEREO OR
MONO VERSIONS AVAILABLE FROM YOUR
STOCKISTS
Icelectrics Limited
IS
Albert Road, Aldershot, Hampshire
Tel
:
Aldershot (0252) 28514
FOR
RELIABILITY
MIX WITH
PARTRIDGE
ELECTRONICS
Manufacturers of Audio Mixers for
Government Education and Broadcast
Authorities
Overseas Clients -use our kits to construct
a Mixer and avoid high import duties
or restrictions
21
-25 HART ROAD
BENFLEET
ESSEX
SS7 3PB
11
::
sound equipment
by
Grampian have manufactured high power sound equipments
for over 40 years. Such experience backs a wide range of
amplifiers, including Battery /A.C. supply types, microphones
and loudspeakers.
GRAMPIAN REPRODUCERS LTD.
HANWORTH TRADING ESTATE, FELTHAM, MIDDLESEX,
TEL: 01 -894 9141
ENGLAND.
Magnegraph Recording Company Ltd
NEW
ELECTRET CONDENSER
TIE-TACK PRO MICROPHONE
PRO NET
zvr,111 A31<>s
S45.00(domestic)
check your nearest
11 to
distributor tor local
4-0i10,*
S
prices.
zn e..
Uses: TV, P A.,
Recording. etc.
1371mm15d,1
i1ri ..
wne
,1).a
Oat,x+ FM F75
/ Mir / / / / / Aar / / AEI / / / / /
Send for NEW Catalog over 280 items for Audio.
SESCOM foreign distributors:
Australia: Klarion Enterprises Pty. Ltd.,
Canada:
Chas. L. Thompson, Ltd., No.Vancouver BC
John R. Tilton Ltd., Scarbough Ont,
England
Future Film Developments. London
Greece:
Laboacustica Hellas. Athens
lemke Roots Import, Amsterdam
Laboacustia Srl, Roma
Roger Arnhott Studio a.s, Oslo
Holland:
Italy:
Norway:
DIN Test Records
So Melboure
DIN
DIN
DIN
DIN
DIN
"QUALITY ENGINEERED SOUND PRODUCTS.
1
12
590, Gardena, CA 90247 USA,TWX 910 -346.7025
STUDIO SOUND, OCTOBER 1975
45541
(Frequency)
45542 (Distortion)
45543 (Cross-Talk)
45544 (Rumble)
45545 (Wow and Flutter)
£5 each and VAT
LENNARD DEVELOPMENTS LTD.
SESCOM, INC.
P.O. Box
1
Small supplies now in stock
1
206 Chase Side, Enfield, EN2 oQX
Telephone: (o1) 363-8238/9
i
\
\
1
1
T1-
New from Acoustic Research
How an
AR speaker
works
Speakers in themselves are simple.
They havefour basic parts: a powerful
permanent magnet, a fine coil of wire
wound on a paper or aluminium form
which is situated in the flux -gap of the
magnet, a cone of felted paper that is
attached to the coil, and a rigid metal
frame that holds all parts in exact
alignment and supports the cone.
When the electrical signal from the
amplifier is applied to the coil of wire,
the coil acts as a small electromagnet.
The strength and polarity of the
magnetic field it generates varies with
the waveform of the music being
reproduced and causes the coil to be
moved alternately outward and inward
by the permanent magnet. This causes
the cone to move back and forth and
generate sound waves.
By itself, a speaker is not a very good
reproducer of sound. This is because
the back surface of the cone radiates
sound just as efficiently as the front, but
out of step with the waves from the
front. At certain frequencies where the
wavelength of the sound is long
enough, the waves produced by the
rear of the corte come around the edge
of the speaker just in time to cancel the
waves from the front. Because this
happens mostly at low frequencies a
speaker operating in free air produces
very little bass response.
To avoid this problem, speakers are
mounted in baffles or boxes to isolate
the front of the cone from the rear. In
effect, the sound from the rear is simply
discarded so that it cannot interfere.
Acoustic Research developed what
has been called the acoustic
suspension or air suspension speaker.
In this system the mechanical stiffness
of the cone suspension is drastically
reduced. The cone is made so loose
that there is virtually no springiness left
even though it can now easily move
great distances at low frequencies.
A speaker like this could not work
properly, however, without some
restoring force to act on the cone. In the
Acoustic Research system, this
restoring force is supplied by the
springiness of a small volume of air in a
tightly sealed box that forms the
enclosure of the speaker. This principle
The AR -11 speaker sys1e m is our laient d ael Dprent
utilising the drivers of the AR -10, except that it does not
feature the woofer environmental control. We believe
it lis the most accurate speaker system ever made by
Acoustic Research.
is now employed by over 70% of
loudspeaker manufacturers all over the
world. Famous musicians and concert
halls have chosen AR speakers
because they liked what they heard.
Have you listened to music yet with
AR?
Acoustic Research International
FIt
ltd--- ltd - - - -- i
PLEASE SEND ME DETAILS OF THE NEW AR
International office:
High Street, Houghton Regis,
Bedfordshire, England
Telephone (0582) 603151
1
Name
1
Address
A
11
1
ILL -IJYN
16
ME MN MN
IM1
MN
I
IM
MN 1111
13
INTRODUCING THE NEW
12 INTO 4 SERIES TWO
BY SOUNDCRAFT
30
1.
00'
Servicers to the music industry
Input Facilities
and studio maintenance and design
Continuously variable mic 'line gain over a 60 dB
range. Switchable 20 dB mic pad before input
transformer. Max mic handling using pad
15 dB
at 20 Hz,
25 dB above 50Hz. Mic line switch, max
line input handling 35dBm.
Insertion point pre -equalisation.
Four band equaliser.
Foldback and echo sends.
Switch for pre -fade listen channel on 'channel mute.
LED peak indicator, fast attack, slow release, full
wave detection set at 5 dB below clipping level.
Slider fader-choice of 66 mm carbon track (standard) or 105 mm conductive plastic.
Panoramic potentiometer, stereo- monocompatible.
Routing push- buttons to: Monitors, Groups and
2, Groups 3 and 4.
1-
1
2.
Specialists in all models of
Revox tape decks, sales, service,
repair, advice and any modification to suit your personal
application.
Collection and delivery. Also
hire facilities available.
Now in stock -THE NEW
TEAC 4 CHANNEL A3340S
105 High Street, Eton, Bucks, SL4 6AF.
Telephone WINDSOR 51403
Output Facilities
Slider fader.
Tape Line monitoring with rotary fader, cue sends
and panoramic control. The four output groups
and monitor returns are selectable by track switches to 8 output sockets and tape return sockets,
the latter being normalised through to the first 8
line inputs. Sockets are provided for foldback and
echo send outputs at line level and 2 echo return
inputs mixing into one return channel with identical
facilities to the mic line inputs.
3. Monitoring Facilities allow push- button selection of PFL, foldback or normal monitoring.
Outputs are provided for both headphones and
MIXERS
Built to your own specification.
Tell us your requirements, we will be pleased to
send a quotation.
line.
Talkback
is provided with level control and
switch to give momentary off hold and
automatic muting of monitors by 20 dB.
5. Line -up Oscillator continuously variable from
100 Hz -12 kHz with level control, output socket and
switch for slate 'off.
6. Choice of Bell spec. VU (standard) or BBC
spec. PPM meters.
Output capability, - 22 dBm into 600!!.
Relative input noise, -128 dBm with 2001! source.
Output noise better than -90 dBm (faders down).
T.H.D. less than .05 %.
Power supply internal (standard), external option.
4.
lever
It's worth asking us for a quote before you buy
elsewhere.
You'll be glad you did !
OLECTRONICS
LIMITED
5 -8
Telephone:
14
Gt Sutton Street, London ECIV OBX
01-251
-36312
3
Telegrams: Soundcraft LDN ECI
STUDIO SOUND, OCTOBER
1975
19
RAC MIXERS
Freemantle Road, Rugby
Tel:
810877
NICE ONE, LES !...
and Tony, Andrew, Brian, Mike , Dick, Eric and David
S
WESTERN NIGERIA
TELEVISION SERVICE
MERCURY MOBILES
(SOU\D VISION)
Eden Vale Road
Woodlanc Industrial Estate
Westbury Wits
Westjury 864120
NOW YOU CAN JOIN THE
PROFESSIONALS
with the
CHYMES AUDIO Mk.3 SOUND MIXER
chymes audio electronic - p. o. box 87- reading, 0734-690177
AUDIO VISUAL SYSTEMS,
5
PARK TERRACE, STUMP CROSS, HALIFAX, WEST YORKS
CE -COURT ELECTRONICS
SUB -CONTRACTORS TO THE ELECTRONICS INDUSTRY
Console and Rack Wiring and Assembly- P.C.B.
Assembly -Mechanical Assembly -Cableform Manufacturing- Protype or Batch -Inspection and Test
Facilities.
For further details of all above facilities
PHONE STEWART CALDECOURT
01 -567 9672/3
CAMBRIDGE TRADING ESTATE,
HANWELL, LONDON W7 3PA
MIKE CABLE
f9.00 PER REEL OF
10
I
The 4
Company
Address
V/IM /I
16
STUDIO SOUND, OCTOBER
1975
100 METERS
-2
RADIO RECORDINGS
(plus VAT)
-
01
-586 0064
. . .
acoustic damping compound, finished in hammer
black paint, and with a heavy duty mounting bracket
to support the pressure unit weight -the 4 kHz
Horn is geared throughout to meet the needs of
BIG SOUND.
your
Name
OFFER
COLOURS AVAILABLE
x 13/0.2MM Cores
with Braided Screen
The 4 kHz Horn is designed for use with the Vitavox
S3 Pressure Unit for wide dispersion of the upper
audio frequencies. Mounted in the vertical position
it gives a wide sound distribution in the horizontal
plane. Made from heavy gauge steel, treated with
I
I
FANTASTIC
WHILE STOCKS LAST
Great Sound
rPlease send me further information on
product range:
(0422- 58600)
KHZ HORN
VITAVOX
Linked
Westmoreland Road
London NW9 9RJ
Telephone: 01 -204 4234
What you see if what you get.
The extraordinary Shure SM7 professional microphone features something
you've never seen before: a built -in Vsual Indication Response Tailoring
System that offers you four different frequency response curves -and shows
you the curve you've selected wGth a graphic readout (see above) at the back
of the microphone! Choose: 1. flat response; 2. bass roll -off; 3. presence
boost; 4. combination of roll -off and presence. And there's more: the SM7
delivers exceptional noise isolation with a revolutionary pneumatic suspension mount ... an ultra -wide, ultra -smooth frequency response ... an integral
"pop" and wind filter ... and a cardioid pickup pattern that looks "text -book
perfect." The Shure SM7 Studio Microphone was extensively field -tested in
recording studios and broadcasting stations! Write:
Shure Electronics Limited
Eccleston Road, Maidstone ME15 6AU
Telephone: Maidstone (0622) 59881
,
s1--11
uRE
17
EXCERPT
OF
OUR
LONG B X 20
USER'S LIST
Austria
ORF
Salzburger Festspielhaus
State Opera
Volksopera
Belgium
BRT -Brussels
Czechoslovakia
CS Broadcasting Corp.,
Praha
Denmark
Danrr arks Radio
Finland
Oy, Yleisradio Ab.
France
ORTF
RTL
SEED
Germany
Bayrischer Rundfunk
Deutsche Grammophon
Gesellschaft
Deutsche Welle
Deutschlandfunk
Hessischer Rundfunk
Norddeutscher Rundfunk
Opernhaus Köln
Polydor International
Radio Bremen
Saarländischer Rundfunk
Süddeutscher Rundfunk
Südwestfunk
Staatstheater Wiesbaden
Westdeutscher Rundfunk
Zweites Deutsches
Fernsehen
Great Britain
Anglia Television
BBC
BRMB Birmingham
Palace Theatre London
Radio Recordings
Radio Tele'is Eireann,
DUBLIN
S. B. Independent Radio
London
Greece
Columbia
Hongkong
Pearce Commercial
Sudios
Jump into ge fL, Inc rever nor ton
Hungary
Magyar Radio,
Budapest
Italy
CAM
CAP
Japan
CBS -Sony
Luxembourg
Radio Luxembourg
Netherlands
Eurosound
Radio Nederland
Norway
Norsk Rikskringkasting
Peru
Sono-Radio SA Studios
Philippines
Audio Empire Studios
Sweden
Sveriges Radio
Switzerland
AKG REVERBERATION UNIT BX 20
Mate wed to three- dimensional hearing. Good reca-dings
indurle the third dimension. But in your ,:Udio a
n;cetsar ly"dea1' recording is created. With the AKG E -X-20
dc
Studia Reverb Unit you can put as much "lie" into
the recording as is needed. A high degree of
tutftsion -exults in natural reverberation quality purely
elecIonic damping for varied decay time from : to 4.5
seconds (1.5 to 3.5 sec alsk available). F.enlote control
obtained over 5000 metres Uicelayed taiEEticn; of decay
t
me during operation. Two ndetenden-
(channel separation
>60da).
=011
isolation against vibration and structuretorn sound
sary.
No locking or re- adjustme-r for transportation ne
Available in 104 countries
a''ll
ever the world.
USSR
Bolscloj Theatre,
cfa -net!
No danger of teediack.
PTT Radio Basel
PTT Radio Bern
PTT Radio Zuerich
Moscow
USA
Bobby Sherman
Eastman School of Music
NBC
New York Philharmonic
OF
OUR
LONG TDU 7202
USER'S LIST
Australia
Opera House. Sydney
Austria
ORF -Vienna
Siemens AG, Vienna
Austrophon, Vienna
Belgium
Broadcast
Cuba
Recording Studio
Czechoslovakia
Broadcast
Denmark
Recording Studio
Egypt
Broadcast
Finland
Broadcast
France
Recording Studio
Germany
:iemens AG, Bremen
avaria Atelier Ges.m.b.
unich
DF, Mainz
iemens AG, Karlsruhe
,WF, Baden -Baden
adio-Bremen, Bremen
Nordwestdeutsche
usikakademie, Detmold
essischer Rundfunk,
rankfurt
TR, Hamburg
DR, Hamburg
WDR, Cologne
homson CSF, Munich
efo. Munich
Tharländischer Rundfunk,)
aarbrücken
liddeutscher Rundfunk,
tuttgart
- tadttheater Wiesbaden,
iesbaden
arbarossa- Studio,
unich
undeswehr-
rp robungsstelle
,reding
orddeutsches Werbe
'ernsehen, Hamburg
Great Britain
Sound Studio, London
Greece
National- Theatre, Athens
Tat protesso
toi, C
\
Hongkong
Recording Studio
Indonesia
Recording Studio
Iran
Broadcast, Teheran
Israel
Sound Recording
Japan
KTD- Postal Authorities,
Tokyo
Luxembourg
Broadcast
Netherlands
NOS (Broadcast)
Philips- Eindhoven
Norway
Recording Studio
Singapore
Recording Studio
South Africa
Broadcast
Spain
Recording Studio
Tunesia
Broadcast
AKG TIME DELAY UNIT TDU 7202
Whenever you require time delayed information
within the sound path - this Delay Unit may solve
panel or remotely controlled. Module technique for
ease of maintenance. Continuous variation of
all your demands in various applications. Delay
delay time is possible within the limits of plus 0 and
times of 0.75 ms to 400 ms are possible. Up to
4 outputs from input. Delay time is
minus 20 %. May be used free- standing
1
independently adjustable for each output from front
or rack -mounted.
Available in t04 countries all over the world.
u Au.A.A.
AAAAAAAAAAAAAAAAAkA
ANNOUNCEMENT
FROM
AUDIO EDUCATION COMPANY
of London
We are not connected in any way with any other Trading concern using
similar name.
a
We are, however, connected with many publishers, A -V producers, industrial training
managers, etc., who, as very satisfied clients, consider us to be the best speech mastering
studio in central London! (we are only 2 minutes from Baker Street tube).
Recording
Location
-
Robert Latham
-
Cassette Duplication - Open Reel Duplicating
and Music producers
Chris Sands
-
Petroff - Maggie Bankart
Hanka Folkierska
- Nasco
-
-
Language
Robert Ahern
Phone 01-723 6635
3
VVYVVVYVYVVVYVVVVVVMMVVVVYMMYVVvvvvv-vmv-vvvvvvvvmmvuv
A Mini Mixer with
PROFESSIONAL
STUDIO
a
AUDIO VISUAL HIRE
true
Tape Recorder Hire
SPECIFICATION
-
Public Address Hire
We do it all
NATIONWIDE
slide exhibition Cabinets, Ferro graph and Teac Tape Recorders, Synchronisers, 16mm
Projectors. Slide Projectors, Overhead Projectors.
Multi- Screen and many more.
Telephone or write for information to
or for the North
EDRIC FILMS LTD
34-36 Oak End Way,
Gerrards Cross, Bucks.
Tel:
Input Channels, 4 Output Groups.
Auxiliary Sends and Echo Returns.
XLR Connectors to balanced Mic Inputs and Line Returns.
Normalled Insert Jacks.
Low Noise and High Output levels.
10
Portable.
Extension units, PPM's, Limiters etc. also available.
South African Agents:
E. J. S.
AUDIOVISUAL SERVICES,
242 D. F. Malan
Drive,
Blackheath, Johannesburg.
Tel. 678 -66 13
RAINDIRK LTD.
20
Downham Market, Norfolk.
Tel. 2165 and 3617
STUDIO SOUND, OCTOBER
1975
EM
84646 & 86521
S
41 Bury New Road,
Prestwich, Manchester.
Tel:
061 -773 -7711 -2
synthesizers
.
.
.
Offer you a professional, highly versatile, complete
electronic sound studio, giving a wide range of
1)
treatments for instrument inputs
2) original sound effects
3)
`standard' synthesizer sounds
... the VCS3
studio model costs £680
+
8% VAT
Electronic Music Studios (London) Ltd
277
Putney Bridge Road, London SW I5 2PT
Tel: 01 -788 3491
Again and again and again
Given the time, the patience, and the money, one
can connect* fifty 303 amplifiers nose to tail so
that the programme goes through one after the
other gradually deteriorating along the way.
Deteriorating? The fact is, that apart from a very
slight background hiss - akin to a good tape
recording - the programme will sound exactly
Products oi
the same at the end as when it started.
*Of course one must fit an attenuator to reduce
the signal back to its original level between each
amplifier.
Send postcard for illustratedleaflet to Dept.SS
Acoustical Manufacturing Co. Ltd.,
Huntingdon PE18 7DB. Telephone (0480) 52561.
QUAD
The Acoustical Manufacturing
for the closest approach to the original sound
QUAD is a Registered Trade Mark
Co. Ltd.
MAGNETICS
total supply capability
from new UK Iactoiy
professional tapes
on the finest polyester base in
2 ",
", 2" and 4" format, in all accepted
lengths, Exclusive PUA dispersion process ensures valuable optimum
balance of signal /noise, MOL at 3% harmonic distortion and print -through
Europe's most modern coater lays it all down right and keeps it right
throughout. Quality is consistently of the highest.
1
-
Lacquer discs
Made by Pyral, originators of the process, and used by leading record
companies throughout the world. Unsurpassed for quality and dependability.
duplicating tapes
3.8mm or
on reels or N.A.B. hubs to DIN or Philips standards. Here again
the PUA assures essential balance. And what price C.60 /C.90 compatibility.
prompt delivery - competitive prices
it's easy to get in touch with
NMI now!
PYRAL MAGNETICS LTD. COURTLANDS ROAD EASTBOURNE SUSSEX ENGLAND
Telephone Eastbourne (0323) 638965
22
STUDIO SOUND, OCTOBER 1975
COMPARE
ADM'S NRC and the `Usual" Consoles!
When you buy an Audio Designs NRC Console, you get a
professionally engineered unit built to the highest
quality standards. And you are assured of "no hassle"
service assistance whenever you need it. But that's
not all. You get extra performance and features not
usually found in the ordinary console.
Look at the'runusual" extras you get in ADM Consoles
ADM FULL -FEATURED CONSOLES
AUDEX
not the "usual" troublesome push buttons
not the "usual" open elements (noisy).
-solid state audio reed switching system
SLIDEX- noise -free linear attenuator with elements sealed against dirt
-bar graph TV screen for monitoring up to 28 audio channels,
....
switchable between peak and average reading.
4 -band, 14 frequency reciprocal equalizer on all it puts
4 sets of Machine Remotes
Full quadraphonic capabilities with 4 joy sticks
Simultaneous multi -track (8, 16, 24 track), quad, stereo and mono outputs.
Complete tip, ring and sleeve patching
VUE- Scan
.
4
2
cue channels
solo systems
5 -Year
Warranty on parts and labor
.
"usual" mess of meters.
"usual" 3 -band.
"usual" one or none.
"usual" one or two joy sticks.
"usual" multi -purpose outputs.
"usual" miniature size or
limited patching.
not the "usual" one or two.
not the "usual" one.
not the "usual" 90 days to one year.
not
not
not
not
not
the
the
the
the
the
.not the
AUDIO DESIGNS AND
Write or call collect
for further information
on the UNusual
ADM Console.
MANUFACTURING, INC.
16005 Sturgeon
Roseville, Michigan 48066
Phone: (313) 778 -8400, Cable: AUDEX
AUDIO
DESIGNS
DISTRIBUTED OUTSIDE U.S.A.
BY AMPEX INTERNATIONAL OPERATIONS, INC.
.
IøLc rclz.ciao
Compare the
features
4- track, Multi -sync Recording
Molybdenum Heads with Original Owner Lifetime
Guarantee
Three Motor Solenoid -Controlled Transport
Adjustable Tape Equalization
Switchable Tape /Source Monitoring
Instantaneous Pause With Locking Feature
Separate Input /Output Controls
MIC ¡LINE Mixing
Large, Illuminated Meters
Electronic Echo and Sound -on -Sound
Then compare
WHY CHILTON MIXERS?
the price!
We are manufacturers in the true sense of
the word; producing Teak Cabinets, Sheet
Metal Work, Tooling. Front Panel and Printed Circuit Artwork etc., our products are
accurate with an attention to detail that is
second nature to us.
The popular M10/2 (10in 2 out) portable mixer
shown is supplied as a basic unit with 10 Line
inputs Inc PPM, Oscillator, LF /HF Equalisers,
1
Aux and PFL. You choose the number of
Microphone or Gram inputs, the channels to
have Presence, Switchable HF /LF Filters or
Ducking. In addition a 2nd Aux channel,
Talk -Back, and /or Compressors can be fitted.
Ring or write for full information, if however
our standard range is unsuitable it may be
possible to modify one to suit your
requirements.
BASIC
input version
12 in 4 out Mkt
M10/2 Mk4
£350.00+VAT
£515.00 -HVAT
16
£565.00 -,
24
01
-876 7957
STUDIO SOUND, OCTOBER
1975
L 31 2
Excluding VAT
That's the Dokorder 8140. Four channel or two channel,
recording or playback, overdub, quadraphonic, sound -onsound, echo
everything you need to help translate what
you feel into what others will feel. Send for full details now.
...
VAT
MAGNETIC TAPES Ltd., Chilton Works,
Garden Rd.. Richmond, Surrey, TW9 4NS
Telephone
Recommended
Retail Price
Imported for you by
AEL
ACOUSTIC°
ENTERPRISES
LTD IlheHï- fideldyPeople
Unit 7 SpaceWaye, North Feltham Tracing Estate.
751 0141(4 lines)
Feltharn, Middlesex .Tel .01-
Tandberg 1OXD.
In the field of professional audio equipment.
you can spend a lot of time piecing together
information, comparing notes on standard and
optional features, across so
many different tape decks.
With all its refinements,
the 10XD means you've hit the
nail squarely on the
head first go.
1. The 10XD will take any spool
up to the 101/2" size you see here.
2. The three speeds 15'; 7 1/2 &
all have the benefit of Tandberg's Qs
r
Crossfield recording technique,
along with the unique
Dolby B facility.
3. High speed accuracy from
the electronic drive with
tachometer control.
4. Behind here are 2 high powered spooling
motors and over here (5) are four
precision Tandberg heads -one more
than you'll get on many units.
33/4"_
All the operating functions of the 10XD
are electronically control led,with the
facility for remote control wherever needed (6).
7. Four input controls.
including 2 for balanced
microphone inputs that allow
you to mix in stereo.
8.9.10.11. Facilities for echo,
sound on sound,editing,cueing
and A &B tests.
12. Peak -level meters.
13. Photo electric stop.
The nice thing about the 10XD,
Q is that you don't need to be a
professional to appreciate all
these qualities. Anyone with an ear
for precision sound reproduction,
will get a thrill out of this machine.
There's a detailed breakdown of the
10XD in Tandberg's special colour leaflet.
Use the coupon to get your free copy, and
the name of your nearest Tandberg dealer.
___
The wonting
r
Please send me complete details
on the 10XD and other
ancillary equipment.
Name
Address
SS/9/170
TANDBERG
Legendary perfection
Send coupon to Tandberg (UK) Ltd., Farnell House,
81
Kirkstall Road, Leeds LS IHR
25
The new TEAC A-7300/2T.
Technology to match your talent.
As a professional, you probably know all about TEAC. Our A-3300 Series tape decks
have helped to set new standards in the recording industry.
Now we'd like to introduce you to the new A -7300/ 2T. A superb 1A track stereo
machine with servo controlled direct capstan drive and full IC logic circuits.
It's an entirely different breed of animal with lots of new features to meet
different demands and needs.
There's a built -in 4 -in. 2 -out mixer. You can plug up to four professional
quality microphones or you can connect up to four line level sources, or combine two mic and
two line sources together.
An Edit button overrides the take -up reel motor. When engaged from the play mode,
this control allows portions of unwanted tape to be easily
14.
removed from the supply reel. And an elapsed time indicator
'1
shows actual minutes /seconds in all transport modes.
A pitch control provides
continuously variable speeds,
plus or minus approximately
T
8% at either of the two
speeds of 15 ips and
7l/2 ips. This can be
used to compensate
for pitch variation of
musical instruments
or as another element
in the creative
recording process.
And of course
there are all the other
advanced features you
expect from TEAC. Master
input level control, dual
concentric output level
control, 3- position bias
and equalisation settings,
10/2 inch reel capacity, and
much much more.
A quarter track
version of the A -7300 is
also available.
Write to the address
below for full literature.
T E AC,
W TELEDYNE ACOUSTIC RESEARCH
High Street, Houghton Regis,
Dunstable, Bedfordshire LU5 5QJ
Telephone: Dunstable (0582) 603151
AUDIO
DEVELOPMENTS
PORTABLE MIXERS
Direct
elRadiator
Integrated
Low Frequency
Full -range
System
Unit
r H.P.D. represents a further out.:tanding improvement of a
loudspeaker system which has become regarded as a quality
standard over the last 25 years by Recording Studios throughout the
world. There is a very good chance that your favourite records and
tapes were monitored on Tannoy Dual Concentric loudspeakers, and
to select these superbly engineered, individually hand -assembled
speakers for your music system assures you of the same professional
performance.
AD
Tire Mori:
ri.i
10'
12"
410 mm
15"
50W
60W
85W
27- 20.000 HZ
25- 20.000 HZ
23- 20.000 HZ
less than 2% less than 2 °p
8 ohms
8 ohms
Impedance via
(5 ohms min.) (5 ohms min
Crossover network
'INTEGRATED PROGRAMME MATERIAL
less than 2%
8 ohms
(5 ohms min.)
260 mm
Power Handling Capacity'
Frequen-y Response
Intermodulation Products
31^
I
031 and
AD 007
The Portable Mixers with the professional qualities
and the professional performance.
Both have
8
inputs that drive into
4
or
2
groups.
All inputs and outputs balanced using XLR
connectors throughout.
Peak Programme Meter to
BS
4297/1968 speci-
fication. (V.U. meter optional.)
Auxiliary for
use on
either echo or foldback.
Stereo linkable compressors on the AD 007.
Extender Units that can incorporate
input modules.
The Cirdacoustic Cone
improves frequency and transient
response. gives much increased
power candling capacity and
greater n ecnanica slab d9y
Patented Magnetic Shunt
combined wit, specially treated
and selected ,reel gives maximum
magnetic flux in the unique
Tenney twin gap system Improves
The High Temperature Voice Coil
o.
handle
;
+. a
Unique High Frequency Unit
with separate diaphragm and
voice coil coupled to the porn by a
19 element phase -matching
System
`+\
Tanopla Surround
gives low bass resonance with
excellent mechanical stability and
freedom from edge reflections
The
assures absolute climatic stability
and great mechanical strength
together with much improved
High Power Crossover Unit
with solid dielectric condensers
throughout. combined with treble
and roll-off controls
T,tiNNOY#
POR WOOD RD. WEST NORWOOD SE27 9AB
Tel : 01- 670 1131 Telex 949755
extra
10
Size: 540 x 480 x 225 mm AD 007
420 x 335 x 127 mm AD 031
Weight: 22.7 Kg AD 007, 10 Kg AD 031
Modular construction to promote serviceability.
Both mixers can be hired and national sound
reproducers of Northolt Road, South Harrow,
Middx are agents for hire in the London area.
There are agents in Belgium, Canada, France,
Holland, Norway and Sweden to date.
Avak
Developments
Hall Lane
Walsall Wood
Walsall
WS9 9AU
g
l
ow
n h
i
l l
s
5351
3
:
27
New Studer
stations is derived from automated
cueing procedures. Within the UK
there are, at present, no installations of this type. Shafer Electronics Inc, 75 Castillian Drive, Goleta,
Ca 93017, USA. Phone: (805) 968
from Studer
utilises the Revox A700 tape transport, but is fitted with electronics
oriented towards the broadcasting
and studio recording fields. The
new A67 is available in several
packages -these include portable,
chassis, rack mounting and console
versions.
Similarly, the machine can be
supplied or changed in service to
the usual track formats within the
6.25 mm tape width; also, the use
of plug-in eq boards allows a ready
interchange of recording standards.
Basic features include full control
logic interlock, vari- speed, mechanical counter indicating minutes and
seconds, remote control facilities,
detachable head block and tape
tension monitoring in transport
modes.
Synopsis of manufacturers' specification referred to operation at
38 cm /s:
Reel type: NAB, DIN and cine to
THE LATEST MACHINE
9755.
UK agents: Mellotronics Ltd, 35
Portland Place, London WIN
3AG. Phone: 01 -637 0755.
Mixer hire -erratum
section of the September issue (p40), we stated that a
series of Audio Design Mixers was
available for hire from NSR Ltd of
Northolt Road, South Harrow.
The mixers in question were in fact
manufactured by Audio Developments of Walsall Wood, Staffs. We
apologise for any resultant misunderstanding.
IN THE NEWS
Manna
26.5 cm.
18k Hz.
Signal to noise ratio (CCIR, weighted,
Agfa PER525 tape, 2.75 mm track width
fluxivity 510 nW /m): 61 dB.
Wow and flutter (DIN 45507 peak
weighted): 0.05" or less.
rw..
Above: Latest machine from Studer,
Below: Low cost 4 channel Dokorder
the A67.
1140.
Studer International AG, CH -5430 as the 1122, the new model features
Wettingen, Switzerland. Phone: 38 and 19 cm /s speed and an inter056 2687 35. Telex: 53682.
changeable head block facility for
USA: Revox Corporation, 155 use with quarter track tape format.
Michael Drive, Syosset, NY 11791. Dokorder Inc, 11264 Playa Court,
Revox Corporation, 3637 Cahuenga Culver City, Ca 90230, USA.
Blvd West, Hollywood, Ca 90068. UK agents: Acoustico Enterprises
UK: F. W. O. Bauch Ltd, 49 Ltd, Unit 7, Space Way, North
Theobald Street, Borehamwood, Feltham, Middlesex TW14 OTZ.
Herts. Phone: 01 -953 0091.
Phone: 01 -751 0141/4.
Low cost four track
THE
NEWEST
ADDITION
to
of people, based in
the Portsmouth area, is setting up
a trust charged with the production
of religious programmes for presentation on local and hospital radio
However, the same
networks.
secular problems face these people
that also face other good causes
lack of hardware etc. They wish to
appeal, through these columns, for
any `obsolete' mixers available from
benevolent readers. They state that
they would be more than happy to
arrange transport. If such a thing
as a free mixer really exists, please
contact David Couchman at 51
Maylings Farm Road, Fareham,
Hants P016 7QS. Phone: 03292A SMALL GROUP
Inputs and outputs: 0 dBm nominal.
Spooling time: 120s for 700m.
Frequency response: =2 dB 30 to
the
Dokorder range of tape recorders
looks possibly the most interesting
development from the company. It
comprises a four track tape machine
on 6.25 mm tape that retails in the
UK for £520. The specification
includes a remote control, 26.5 cm
reel capacity, high speed (19 and
38 cm /s standard), simul -sync, over
dub/echo and limited memory
rewind facility. The machine, type
1140, is available in standard
wooden console and rack mounting
format.
Also recently available is a half
track version of the 1120. Known
28
STUDIO SOUND, OCTOBER 1975
Automated broadcasting
the UK agents
for Shafer Electronics Inc, has
announced the sale of a 903 automated broadcast system to the
Gibraltar station of the British
Forces Broadcasting Service. The
complete installation comprises the
903 memory system offering a
programming capacity for up to
400 sequential events and 1440
timed events, network or studio
join facilities, four PB720 reel to
reel tape reproducers, two ITC
single cartridge machines and a
Shafer 36-cartridge random access
Audiofile. In addition, there is a
custom - built interface allowing
automation of the existing Ampex
351 recorders.
The installation
includes equipment to record the
cue tones on the programme tapes.
The manufacturers claim that the
benefits of the system include a
reduction of the non -social hours
working by the operating staff and
a general improvement of the
standard of presentation of programme output. Recent surveys
suggest that up to 20% of programme output of US broadcasting
MELLOTRONICS LTD,
-
5391.
AES 53 Zurich
THE 53RD CONVENTION Of
the Audio
Engineering Society will be held
from March 2 to 5 at the Hotel
International, Am Marktplatz, CH8050, Zurich, Switzerland. Following the pattern of other conventions
on the international AES circuit,
the Zurich venue will include a
programme of technical papers, a
show case for manufacturers' products and the opportunity for
delegates to visit various electronic
firms and recording / broadcast
studios in the vicinity of the
exhibition.
For those wishing to submit
30
PERFORMANCE
PLUS
TECHNICAL SPECIFICATION
Mean sensitivity open circuit voltage per dyne /cm2
(micro bar) 0.064 mV
Open circuit voltage level per micro bar reference
1 volt -84 dB
4037A Moving Coil Microphone ideal for
Television Interviewing
Power delivered into 30 ohms for 1 micro -bar reference
1
mW -76 dB.
American A.S.S. rating reference 1 mW -150 dB.
Nominal impedance 30 ohms.
Distortion less than 0.5% for a sound intensity level
of 125 dB above 0.0002 dynes /cm2 (20 micro -newtons
per square metre) at 500 c /s.
Dimensions: length 21.3cm, mean diameter 2.54cm,
weight 260gm.
Response curve is sensibly flat from 30 c/s to
12,000 cis for sound incidence within a solid angle
of 30°.
IHINIF
Hampstead High Fidelity,
This microphone is unobtrusive, and neat in appearance,
and is therefore ideal for television and sound
interviewing. It is finished in black shrivel enamel and
satin chrome. There is a special locking device
to prevent it becoming accidentally detached from the
4069A Jack during use. The response of the
microphone to wind conditions is reasonably low, and
in severe wind conditions a P.A.S. 45/39
windshield is recommended, this will permit speech
clarity. A first class professional inside and outside
broadcast omni -directional microphone.
91 Heath Street, Hampstead London NW3 6SS
Telephone 01 -435 0999 and 435 6377
29
NEWS
papers for presentation at the
convention, the closing date is
September 25. Applications for
exhibition space should be addressed to G. K. Ullman, Philips AG,
Dept AVT, PO Box CH-8027,
Zurich, Switzerland.
French connection
French company
Acousmat: Apollo Electronics,
formerly of Mill Hill, London NW..
The new group will manufacture
the established Apollo range of
modular mixer components at a
production facility based in France..
Further information may be
obtained from Michel Guedj of
Acousmat /Apollo Electronics., 22
Rue Ste Ambroise, Paris 75011..
TAKEN OVER BY the
France.
Phone: 357
16 97.
Low cost oscilloscope
BEING IDEAL FOR investigating phase
relationships and relative signal
levels, the 4D -10 dual trace Scopex
'scope should find applications in
recording studios for desk and tape
machine alignment. Incorporating
a 6 x 8 cm display, the unit features
a 10 MHz bandwidth, a trace
locate facility, full speed deflection
sensitivity down to 10 mV /cm (y
axis) and internal time base speed
to 1 ps/cm.
The unit costs £118 from Scopex
Instruments Ltd, Pixmore Industrial Estate, Pixmore Avenue,
Letchworth, Herts SG6 1JJ. Phone:
St, New York, NY 10016. Phone:
Details of these and other courses
(212) 661 -2355, telex: 620298 UW. is available from the Department
Due to later availability of paper of Electronic and Communications
and exhibitor information, the Engineering (room 2/8), The Polypreview may appear next month technic of North London, Hollo(November, published October 14). way, London N7 8DB. Phone:
01 -607 6767 Ext 287.
Engineering courses
THE POLYTECHNIC OF
is offering a range
North London
of courses on
audio engineering and acoustics for
the year 75/6. Starting in October,
a course in electronic and corn munications engineering,with audio
engineering as a specialisation,
results in a new B.Sc (CNAA)
degree.
The duration is three
Didn't they do well
3
Cadac are very happy
after winning an order to supply
the Vogue Studio, situated in
Villetaneuse, France, with a 28/24
format desk which is also equipped
to do quadraphonic mixdown work.
04626 -72771.
years.
Initially, 16 output groups are
Concurrent
for
part - time provided but these will be expanded
students, a one-year course in to 24 in the foreseeable future. Other
AES 52
THE
SIND AUDIO Engineering sound
studios and recording features of the desk include four
Society Convention will be held at exempts students front the finals echo sends and eight echo returns,
the Waldorf Astoria, New York, of the degree mentioned above. four separate foldback circuits and
between Friday October 31 and Continuous student assessment is full equalisation. Installation work
Monday November 3.
Fuller by the City and Guilds of London is expected to start about Christdetails from AES, 60 East 42nd Institute. The entrance fee is £15. mas. Cadac consider this order to
FIRST OF ALL,
60*
1
4
2
3
5
6
7
Diamond Cutting
JVC's new Mark III cutting system, on which a paper was presented at the recent Los Angeles AES show, has now
been in service for some time. The cutting chisel is of diamond, with a lamination of tungsten carbide on the
trailing facet to prevent lacquer adhesion. Significant improvements are claimed in half-speed cutting, as indicated
best by the accompanying photographs, taken by JVC using scanning electron techniques.
30
STUDIO SOUND, OCTOBER 1975
1.
Sapphire cutter after 40 lacquer faces operation.
2.
Diamond cutter after 120 lacquer faces operation.
3.
Diamond cutter, showing left and right burnishing facets.
4.
CD -4 carrier cut with new sapphire.
5.
CD -4 carrier cut with sapphire after 15 hours use.
6.
CD -4 carrier cut with new diamond (black above centre is photographic print damage).
7.
CD -4 carrier cut with diamond after 15 hours use.
B10110 channel
810214 to 32 input,
4 sub group, 2 main
2
output control
group mixing
console.
console.
input, 4 group, 2 mains output
console fitted extra foldback and
14
Commercial radio central area control,
monitoring and distribution rack equipment.
Radio self- operated control
console - custom built to
monitoring facilities.
D. J.
requirements.
Consoles
Sound Control Consoles, 2 & 4 group Transportable Mixers Radio Continuity
Self-operated Consoles Gram. Consoles Audio Switching Matrices Distrioution Amplifier systems
Rack mounting limiters and compressors Intercom. systems
Control line switching systems Monitor amplifiers Line equalising amplifiers
EI LJ 11 X
MANUFACTURERS OF
SOUND SYSTEMS AND
ELECTRONICS
AUDIX LIMITED STANSTED ESSEX CM24 3HS
S
TELEPHONE: BISHOP'S STARTFORD 813132
(4 lines) (STD 0279)
31
11111MMIDIMI
Dear Sir, Thank you for calling to see me
recently. I'm glad we were able to air our
views on the studio write -up.
I thought I would just confirm the couple of
points I was not happy with. The first is that
I am not the founder of the company. My
father, who started the company, has been
involved in sound for nearly 50 years and the
credit must go to him. It was probably people
like him and Joe Meek who helped break the
monopoly of the major studios like EMI and
Decca, allowing the present -day influx of
independents.
My other quote, as you agreed, was taken
out of context concerning the 3M Selectake.
My comments were that `the basic machine is
very good' (meaning the Selectake, not the
M79; the M79 is superb!) but you can't beat
a good tape op', which I feel is fair comment,
not criticism. No mention was made of the
M79 machine causing an oscillatory situation
etc.
Hope you don't think I'm being `very silly
indeed' writing to you.
Yours faithfully, Robin Jones, R. G. Jones Ltd,
Beulah Road, Wimbledon, London SW19.
Dear Sir, In the July issue of STUOto SOUND,
reference was made in the R. G. Jones Studio
article by Frank Ogden to the 3M Selectake
tape search unit used by this and many other
professional studios throughout the country.
The article implies that the 3M M79 series
professional multitrack recorder affects the
successful operation of the Selectake unit. This
is quite incorrect. The Selectake is designed to
operate with the M79 series recorders and is
available as an optional extra. In this case,
the dog does not wag the tail; the tail wags the
dog!
The article also implies that the Selectake is
a rather cheap and nasty device which can be
beaten to the gun by the recorder operator.
When we were telephoned by the author and
questioned about the unit, we informed him
that the 3M device operates by overshooting
both in forward and reverse mode until the
desired preselected tape position is reached.
We further informed him that there were other
devices available which operate by braking in
one direction only, and while these were
perhaps faster, they were also more expensive
than the 3M unit. Unfortunately, Frank
Ogden reduced this information to: `3M
comment: "At the price, we do not see this as
a fault" '.
A typical use of the Selectake unit is as
follows: during a recording session, the
operator notes and logs take starts as indicated
on the unit's readout tubes. When replays of
certain takes are required, the previously
recorded take starts are set on the preselector.
The appropriate mode (forward or rewind) is
initiated on the recorder, upon which the
Selectake commands the recorder to stop at
the preselected location within +2 counts of
the readout counter.
It would be appreciated if you could publish
the above and so set at rest the minds of our
many customers who might have been led to
believe that they had purchased an inferior
piece of equipment -or worse still, that their
M79 machine was in some way incompatible
with the Selectake unit.
Yours faithfully, Bill Bowles, Public Relations
Executive, Recording Materials Division, 3M
UK Ltd, 380 -384 Harrow Road, London W9.
regret that my comments in the R. G. Jones
article concerning the operation of the Selectake
gave so much cause for concern. The comments,
quoted verbatim, were lightly made and, as
such, lightly written. It was never the intention
to sit in judgement on the operation of the
device. The place for such a judgement is clearly
within the review columns of the magazine.
However, in context, the remarks can be
defended. Bill Bowles of 3M stated that the
Selectake operates by `overshooting both in
forward and reverse mode until the desired
preselected tape position is reached'. Technically, this is an oscillatory situation ever: if
damped. `Oscillatory situation' was my description and did not originate from Robin Jones. It
was never intended to criticize the operation or
performance of Robin's M79 machine. All
remarks related totally to the Selectake. -Frank
Ogden.
1
Dear Sir, We would like to thank Angus
McKenzie for his helpful comments in his
review of our 12/4 recording console. By the
time this edition of STUDIO SOUND goes to
press, the new 12/4 Series 2 will be in production, superseding the model under review and
embodying many improvements, certain of
which are suggested by Mr McKenzie.
In particular, we have lowered the nixing
point noise by a further 6 dB from that finally
obtained on the review sample, and have
increased the line input level capability to
+35 dBm. Output of the desk is now -i -22 dBm
into 6000.
For a more detailed description of the new
34
Broadcast pattern audio jackfields
from Future elm Developments
19" Rack
Mounting, from one
to six rows of 20, 24, or 26 jacks. The
Jacks are mounted on a plastic block which is
in turn mounted on a 19" panel. Each row is fitted with a
legend (designation) strip and wire support bar. The panel is steel,
cadmium plated, chromate passivated and stove enamelled hammertone silver.
32
STUDIO SOUND, OCTOBER
1975
ALSO Audio Patch Cords Microphone Cable
Installation Cable Multiway Cable Post Office &
Rendar Jacks Cable Markers Lever Keys Linear
Faders Cannon Connectors Preh Connectors
Tuchel Connectors Switchcraft Connectors Military
Tri -Lock Bayonet Connectors Audio Attenuators
Wahl and Weller Soldering Irons PML Microphone
Accessories Hellermann Sleeves and Tools Crimp
Terminals Cable Drums A.B. Engineering Wire
Strippers and De- Solder Guns.
FUTURE FILM DEVELOPMENTS,
90 Wardour Street, London W1V 3LE.
Tel: 01- 4371892 Telex: 21624
0.
- '-1-I
ze::::::rnc
20Hz -20KHz bandwidth and
200 ohm source
-129 dB referred to OdB
(filters -1.5dB at 20 Hz and 20KHz,
12 dB /octave)
..
..
(.
r
.ßaí
.,
}'i,
±5dB 20Hz -20KHz
.
overall gain switchable 80 /100dß
S
foldback send, aux send
and return
r
r V
band EQ
frequency response with controls
in flat positions
`
!M
-4K0
4...
""
` . '- -.
`
'
;
4
-.
4 output groups
output clip point +18 dBm
(unbalanced)
`>g
4 output limiters with
variable output and release time
(2945
31
stereo monitoring via
STATION ROAD, LONDON, S.E.25. SAIT
Telephone:
01 -653
h /phones
A/B switching
talkback and slating
and outputs with
6018/8483
facility
MIXER
THE PEAVEY 9200
12
unbalanced, high impedance line inputs
and low equalization on each channel
Three send controls on each channel, all having pre or post capability
pan on each channel
Output slide attenuators on each channel
Master control area consisting of left & right main slide attenuators
with associated low, middle & high equalization and monitor slide attenuator.
Reverb master, return, & pan controls
Effects master, return & pan controls
600 Ohm transformer balanced outputs on left & right main and monitor
Lighted VU meter on left & right mains, externally adjustable.
12 transformer balanced, low impedance mike inputs
Input attenuation & mike /line selection High
Stereo
NAMASINIMMUSISliti
iggglInggNHNN
1
11111411
&EN riEritrigamlig
tie
:iiU
/1111111
'
Sig SE
1
.
,
11l
PEAVEY ELECTRONICS CORP. / 711 "A" Street / Meridian, Mississippi
33
In
ibi
d
LETTERS
desk we refer the reader to our advertisement
in this issue (excuse the plug).
Yours faithfully, Graham Blyth, Technical
Director, Soundcraft Electronics Ltd, 5 -S Great
Sutton Street, London ECI V OBX.
See p86
How else would you describe a
preamplifier with:
* A Peak Unlimiter that restores
dynamics lost in recording to
closely approximate the original.
* A Downward Expander that reads
"gain riding" and expands
dynamics down to precisely the
intended level.
An AutoCorrelator that makes
record /tape hiss and FM broadcast
noise virtually vanish without
affecting musical content.
e Plus an Active Equalizer that gives
you flat energy distribution over
the full audio spectrum, Joystick
Balance and Step Tone Controls
that allow precise music tailoring
to your listening environment and
SQ* and Phase Linear differential
logic for Quad Sound.
The 4000 is an advanced stereo
preamp that actually puts back in
what recording studios take out
lets your music (at last) reach life -like
levels without distortion
lets you
(for the first time) hear your music
from a silent background. It is, in a
word, incredible. Ask your dealer
for an audition.
Warranty: 3 years, parts and labour.
...
...
,/-teae
cr,bietf/t
4000
THE POWERFUL DIFFERENCE
PHASE LINEAR FAMILY
Main Agents
Exposure Electronics
Richardson Road
Hove, Sussex
BN3 5RB
34
STUDIO SOUND, OCTOBER 1975
-Ed.
Dear Sir, Permit me to write to you about the
review of the Telefunken M12 recorder in the
May issue. Since we represent Telefunken in
the USA we are naturally interested to see that
no errors creep into such reviews. I would
have written to Hugh Ford, an old friend,
directly, but thought you'd like to read my
comments and then pass them on to him.
He mentions two `lethal' items to which the
Hayden people replied in their letter on p. 62
but to my way of thinking did not sufficiently
cover the necessary reply.
1) As for tape motion logic: I realize that the
general tape recorder manufacturing industry has slipped ever more towards the
lower market levels, and in these such
`baby logic' might be needed. I have yet
to encounter a serious -minded engineer
who doesn't bristle at the thought that
such logic is necessary, and who does not
object to spending money on such `frills'
to the detriment of audible quality, on
which Telefunken has obviously not
skimped. It is a fact that such logic is in
the works at Telefunken, though.
2) The matter of the record button interlock,
however, is quite another matter! We
refer to section 2.3.5 on p. 2 -6 of the 11112
Manual which says: `The M12 offers two
possibilities:
Record can be preselected using the
RECORD button. The PLAY button
starts the tape.
Record is only activated when both the
RECORD and PLAY buttons are
pushed simultaneously.
The second option is obtained by
removing the diode between solder
points 5 and 6 on the printed circuit
board B-LCI.' At the head of that
paragraph it further says clearly: `To
switch to record mode, both RECORD
and PLAY buttons must be pushed'.
That's the good old way
trust this clears up what could really be an
unfair comment.
It would be very nice if my comments could
be included at some near future time in the
letters column as well.
Yours faithfully, Stephen F. Temmer, Gotham
!
I
Audio Corpn, 741 Washington Street, New York
NY10011.
would thank my friend Steve Temmer for his
interest in my reviews, and for his comments
upon the Telefunken M12 review.
While I
appreciate Mr Temmrer's remarks about 'logic'
and do agree that in some instances logical
interlocking can be excessive, with consequent
unnecessary expense and decreased reliability,
we must keep our feet on the ground.
`Logic' is a word which has crept into the
audio industry over the last few years, and for
some reason is regarded with trepidation by
audio engineers, possibly because it is associated
with digits and computers, which audio people
have no wish to understand! in days of old the
'logic' was achieved by multiple interlocking
mechanical switches, which are expensive,
unreliable bits of bent tin -these switches were
used to drive mechanical relay logic. Now, what
is wrong with replacing these mechanical
contraptions with small, cheap, reliable integrated circuit logic?
Provided that modern logic is properly engineered, it is extremely reliable and adds little to
the cost of a professional equipment and can be
a valuable safety feature. The cost of a master
tape bears no comparison with the small expense
of logic required to protect it from mechanical
or magnetic damage.
Turning to the matter of the record interlock,
I reported on the machine as delivered. assume
that it could well have been delivered to a studio
in the same state. Unfortunately at the time no
instruction or operation manual was available,
but subsequent events confirm that two interlock
erodes are built into the machine. -Hugh Ford
I
I
Dear Sir, Your long overdue articles on disc
cutting are much appreciated. A comment or
two on Tony Bridge's piece. Surely, some of
the information given in the Monty Python
record story was either incorrect or incomplete
or else George Peckham took on a much
...
98
MICROPHONE
PREAMPLIFIER
A two -channel circuit board convenient for stereo
but with good enough crosstalk performance to
allow use on two separate signals. The inputs are
balanced with taps to suit 30, 200 or 600 ohm
sources when the worst case noise figure is
1.5 dB. The frequency response is smooth, being
within 0.5 dB from 20 Hz -20 kHz. There are gam
presets on the board and normal use would be for
a nominal output of -10 dB (V.7) leaving a headroom of 25 dB (24V supply and 5K ohm output
load). Maximum distortion is 0.01 "4, at -10 dB
(V.7) output and 0.1
at 4- 10 dB (V.7). Precautions are taken in the amplifier design to
minimise radio interference.
Available built and fully tested or as a kit.
* DISTRIBUTION
STEREO DISC AMPLIFIER
AMPLIFIER * PPMs * FREQUENCY AND
SPECTRUM SHIFTERS
SURREY ELECTRONICS
The Forge, Lucks Green, Cranleigh, Surrey
Telephone STD 04866 5997
GU6 7BG
11044
44.40;,
Do you want
to save
MONEY?
then contact us
Specialists in Audio Control
equipment for Broadcast and
Sound Recording Industry
TWEED
ELECTRONICS
ROSEWDOC INDUSTRIAL ESTATE, KELSO. RCXBURGHSHIRE
STD 05732
TELEFHONE 2983
SCOTLAND
1111M1101011
THE FOLLOWING list of complete Specifications Accepted is quoted from the weekly
Official Journal (Patents). Copies of specifications may be purchased (33p) from the Patent
Office, Orpington, Kent BR5 3RD, UK.
July 2
1402508 ZCM Ltd.
System for conveying sound information to the
brain.
1402609 Ellanin Investments Ltd.
Noise reduction system for video signals.
1402681 International Business Machines
Corporation.
Tunnel erase transducer assembly.
1402695 International Business Machines
Corporation.
Apparatus for unloading laminar members
from a cartridge.
1402700 Osterreichische Studiengesellschaft
Fur Atomenergie GMBH.
Method of and apparatus for producing a
colour display of the surface of a solid body.
1402809 International Business Machines
Corporation.
Semi -conductor circuit elements.
1403019 Siemens AG.
Output amplifier short -circuit protection
circuits.
1403020 Hell GmbH, Dr -ing Rudolf.
Hot -point stylus writing systems.
1403097 National Research Corporation.
Earplugs.
1403110 Eaton Corporation.
Signal isolation system including a phototransistor.
July 9
Gabr, S Z M.
Loudspeaker cabinets.
1403360 EMI Ltd.
Television camera arrangements.
1403383 Minnesota Mining & MFG Co.
Composite film structure.
1403386 Matsushita Electric Industrial Co.
Ltd.
Data recorder.
1403486 Novanex Automation NV.
Transistor amplifier.
1403488 Burroughs Corporation.
Gas display panel for colour television.
1403519 EMI Ltd.
Apparatus for the automatic registration of
signals.
1403695 Bosch
Fernsehanlagen
GmbH,
Robert.
Picture signal correction system.
1403804 EMI Ltd.
Magnetic tapes.
1403354
July 16
1403997
International
Business
Corporat ion.
Waveform communication system.
1403998 International Business
Corporation.
36
Machines
Machines
STUDIO SOUND, OCTOBER 1975
Waveform Communication system.
1404029 International Nickel Ltd.
Magnetostrictive methods and apparatus.
1404031 International
Standard Electric
Corporation.
Horizontal deflection circuit for television
receivers.
1404083 Matsushita Electric Industrial Co.
Ltd.
Magnetic recording and reproducing apparatus.
1404093 Singer Co.
Simulator visual display system.
1404237 Matsushita Electric Industrial Co.
Ltd.
Magnetic recording and /or reproducing
apparatus.
1404239 Rank Organisation Ltd.
Discriminator circuits.
1404279 Ambitex Corporation and Cendev
Corporation.
Acoustic feedback stabilization system particularly suited for hearing aids.
1404320 Defence, Secretary of State for
Recording tape devices.
1404460 Standard Telephones & Cables Ltd.
Device for transmitting cursive script or drawing over a telephone.
1404483 Arvin Industries Inc.
Process and apparatus for magnetic disc
recording.
1404484 Arvin Industries Inc.
Magnetic record disc.
July 23
International Business Machines
Corporat ion.
Information storage system.
1404589 Plessey Co. Ltd.
Electrical information store.
1404590 Defence, Secretary of State for
Radio signalling equipment.
1404613 Dayton Wright Associates Ltd.
Assembly comprising an electrostatic transducer in an enclosure.
1404618 International Business Machines
Corporation.
Magnetic disc memory and component.
1404645 Telefonaktiebolaget L M Ericsson.
Circuit arrangements including amplifier
circuits.
1404672 Hell GmbH, Dr -ing Rudolf.
Apparatus for the reproduction of pictorial
1404541
images.
1404718
GTE Sylvania Inc.
Horizontal deflection circuitry for cathode ray
tube system.
1404802 Fuji Shashin Film KK and Ikegami
Tsushinki KK.
Colour television signal generator.
1404945 Siemens AG.
Data display systems.
1404961 Standard Telephone & Cables Ltd.
Measurement of timing jitter on PCM systems.
1404988 Perkin -Elmer Corporation.
Dynamic filter.
1405141 Matsushita Electric Industrial Co.
Chemiebau Dr a Zieren GmbH &
Co. KG.
Electroacoustic transducer elements.
1405154 Siemens AG.
Telecommunications line -state monitoring
circuits.
1405149
July 30
Johnson Service Co.
Microwave cavity oscillator tuning element.
1405285 Ferranti Ltd.
Semiconductor information storage devices.
1405297 Mitsumi Electric Co. Ltd.
Semiconductor impedance circuit.
1405298 Mitsumi Electric Co. Ltd.
Semiconductor impedance circuit and applications.
1405409 EMI Ltd.
Colour Television cameras.
1405445 Sony Corporation.
Transistor circuits.
1405450 Hitachi Ltd.
Pulse generating circuit.
1405542 1RD Mechanalysis Inc.
Direct reading phase meter.
1405614 Morat GmbH, Franz.
Method of and apparatus for recognising colours.
1405644 Bulova Watch Co. Inc.
Incrementally adjustable capacitor unit for
tuning a crystal -controlled oscillator.
1405675 Compagnie Honeywell Bull.
Read head for an optical character -recognition
system.
1405699 International Business Machines
1405216
Corporation.
Optical image sensors.
1405706 ELMO Co. Ltd.
System for synchronizing motion picture
apparatus with tape recorder.
1405723 Soc
Italiana Telecomunicazioni
Siemens Spa.
Vertical deflection circuit for a video terminal of
a data transmission system.
1405781 Hewlett- Packard Co.
Electronically tunable acousto -optic filter
having selected crystal orientation.
1405789 Kureha Kagaku Kogyo KK.
Electroacoustic transducer.
1405827 Mullard Ltd.
Transmission -line amplifier.
1405870 Quadracast Systems Inc.
Decoder for multiple channel FM signal.
1405881 Image Analysing Computers Ltd.
Information selection in image analysis systems
employing line scanning.
1405882 Image Analysing Computers Ltd.
Information modification in image analysis
systems employing line scanning.
1405903 Technicolor Inc.
System for processing signals representing
colour images.
Ltd.
1405933 GAF Corporation.
Video reproduction system for photographic
and other images.
1405996 Honeywell Information Systems Italia
Spa.
Apparatus for displaying a computing function.
Magnetic tape guiding device.
SECOND PATH
21
10
14
FR UER
i
N< -22
GAIN
ourvur
hVPUT
FIRS
f lOd
PATH
GA/N
Top left:
bottom left:
FIG. 2, centre above:
FIG. 3, below: FIG. 4
and above right:
FIG.
I
VIII
-IOdB
I
i
OdB
1,
lob
10d
(c)
IOdB
f0
i
i
I
/
f
I
FREQUENCY
Is
lib
lit
f3 121 411112 f3
lla
fe
FIG. 5
THE RECENT ISSUE of a string of three
new patents from Dolby Laboratories Inc.
(BP 1390341, -2, -3, and the US equivalent,
3845416) is especially interesting because it
provides possible pointers towards future areas
of Dolby commercial development.
Both BPs 1390342 and 1390343 relate to
what appears to be a new avenue of thought
for Dolby Labs. The patents explain how
breathing noises can be avoided by ensuring
that various parts of the frequency spectrum
are treated independently of each other, for
instance so that noise reduction in the high
frequency range is not influenced by signal
levels at low and mid frequencies. It is of
course also well known by now to route
different signal components along different
treatment paths. The new idea is to provide
for separate treatment by arranging for variable
coupling of separate treatment paths to control
the degree of compression and expansion on a
level and frequency-selective basis.
In the basic circuit of BP 1390342, the signal
is split between two paths and recombined by
a variable coupling means. Fig. 1 shows the
concept block schematically and fig. 2 shows a
compressor working on the basic principle.
The first path is a direct connection from
input 10 to variable impedance coupling device
20; for instance, an fet or photo- resistor.
The input is also connected to the coupling
device 20 by filter paths 15, 16, 17, 18, which
provides a high frequency boost. The signal
level in the circuit is sensed across coupling 20
by control circuit 21 and, as the control signal
increases, the resistance value of coupling 20
is reduced.
The controlled change in the value of
coupling 20 means that when the input signal
level is low the output signal has a high
frequency boost, and when the input signal is
of high level, high frequency content, this hf
//
INPUT LEVEL
-40dB -30
I
-20
+10
/ //
-10
26
- -10
- -20
- -40dB
boost is eliminated. Thus, the circuit operates
as a signal compressor at high frequencies only
and expansion by a complementary circuit can
provide high frequency noise reduction at
10 dB.
In BP 1390343, a generally similar circuit
(fig. 3) has a circuit path 14, which is completely linear, and a path 11 which is linear
with respect to dynamic range but not with
respect to frequency. Again there is signal
sensing across variable coupling 17, and control
circuit 19 operates such that when the signal
in path 14 is low, coupling 17 is of high resistance value and the signal appearing at output
terminal 18 is contributed almost exclusively
by the path 11. On the other hand, when the
signal is high, the value of 17 is low, and the
signal appearing at output 18 is contributed
almost exclusively by the path 14. Fig. 4 shows
the transfer characteristics of the two paths,
and 14, as 11 a and 14a.
Below the turnover frequency of the filter,
the characteristic I la coincides with the
characteristic 14a, whereby there is no compression; above the turnover frequency, there
is high frequency boost. Thus compression
occurs selectively in the high frequency band
only, and the suggestion is that the system will
be used to give noise reduction above 3 kHz.
Another suggestion is that any number of
paths can be used, and their characteristics
altered to provide special audio or video effects,
for instance in electronic music synthesis.
BP 1390341 (USA 3845416) adopts an
entirely different approach. The concept of
using multiple signal paths and either varying
their characteristics, or fixing their characteristics and varying their combinations, is
abandoned. Instead there is a proposal that
only a single path be used. This will work on
the narrowing band principle, to confine
compression, expansion and noise reduction
to frequencies where only low-level signal
11
components are present.
Fig. 5 shows compressor characteristic l0a
and expandor characteristic I la extending over
an overall frequency band between frequencies
Fo and F,. Below frequency F1, gain is unity,
and between F1 and F3 there is 10 dB boost.
However, in accordance with the invention,
a narrowing band principle, when a high level
component appears at a frequency F2, lying
between F1 and F,, the band of boost slides
upward and narrows. As a result, unity gain
extends through F1 and up to F2 which boost
applies only between F2 and F3. Thus, the
strong signal component at frequency F2 has
eliminated compression and expansion between
F1 and F2 but not between F2 and F,. Various
circuitry utilising series connected impedance
networks is described, to achieve the theoretical
principle described.
37
1111AIC ti
Aussie Festival
have what is
reported to be the largest and most
ambitious Australian recording
studio. Commissioned in April
last year, it accommodates 50
musicians within its 15 x 11.5 x
4.5m. Construction of the playing
area is along 'room within a room'
lines, with walls, ceiling and 10 cmthick concrete floors floated on
`silentbloc' rubber vibration absorbers; the inner shell is then
adjusted for appropriate acoustical
performance and relies on the outer
room and its separate 15 cm concrete walls and 30 cm concrete floor
to squash air -borne sounds.
The original studio acoustics
have been redesigned, with a
mechanical reverberation control
system based on acoustic panels
suspended from a ceiling track
system this apparently allows a
high degree of control over the
FESTIVAL RECORDS
studio reverberation time. Further,
these panels can be swung round
to reduce the apparent studio size
by two thirds; along the same lines,
and basically for the same people,
is provided multicoloured dimmer
lights, even in the vocal booth;
thus, surroundings are even more
variable to suit the clientele of the
moment.
Control room is designed around
a 28 input Neve console with
extensive monitoring and simultaneous four, two and one track mix
outputs. The 24 track MCI tape
transport uses the full automated
locator system, but in addition has
noise gating on all channels in
conjunction with the 24 M Series
Dolby A noise reduction modules.
Monitoring is via JBL 4320s and
Crown (Amcron) DC300As. Outboard equipment includes Eventide
Instant Phaser, six Kepex and two
Gain Brain units from Allison
Research, limiters, compressors and
graphics from UREI, Cooper Time
Cube, six Neve limiter /compressors
and two Inovonics hf limiters.
The microphone complement
reflects a policy diametrically opposed to the common one of standardisation, which is a particularly easy
and attractive proposition when
re-equipping or setting up. It's
worth going through the list, which
is an unusually wide spread across
types new and old: Neumann 2 x
U17, 2 x U67, 4 x U17i, 4 x U87i,
6 x KMS61. AKG 2 x 452E, 2 x
D12; Beyer 2 x M160, 4 x M88;
Altec 2 x 6s5B, I x 21C; Electrovoice 2 x REM; Sennheiser 4 x
MD411 U; Shure 2 x SM53, 2 x
SM57.
In addition to the recording
facilities is a cutting and pressing
installation, the former with mono
in an Ampex 351 -Haeco GW120ANeumann AM32 -Haeco SC2 chain,
stereo Scully T/M -Haeco SD240Neumann VMS -Haeco SC2. Pressing starts with the spray silvering
master lacquer processor, hopefully
to be supplanted by a fully automatic system which is at present at
design stage. Then follow 14 master
matrix processors, 24 mother/
stamper matrix processors and 26
Alpha semi - automatic record
presses.
Michael Thorne
Wheeling
`WHAT DO YOU mean, why?
Above: Festival Records' Studio. Below:
Gone to tea.
It's
because everything's got wheels,
that's why. And then there was
that animal, you know. So His
Master's Wheels seemed right.'
It all grew out of a Neil Young
tour in 1973 and Elliot Mazer's
finding conventional studio hiring
rather expensive; more expensive,
in fact, than putting together his
own mobile based in a 10.5m
articulated truck.
But after a
winter which, on the East Coast,
proved hard for mobile work in
general and HMW in particular,
Elliot moved out to San Francisco,
into partnership with Alembic,
and installed their gear. Engineering strength now includes Jerry
Zatkin in what remains a small,
close-knit operation, with Gary
Haber, as (just departed) manager.
Shortly after, they bought out
Alembic's interest in the studio
operation and set about putting
everything on a fully commercial
footing and as independent as
possible of Elliot's productions
which, although plentiful, could
38
STUDIO SOUND, OCTOBER
1975
not be expected to provide a steady
basis to finance a large studio. And
thus they developed through to
present -day prosperity, but without
losing the remote side of things.
One fairly special outing was
when Crosby, Stills, Nash and
Young asked them to record for
three days in Washington DC,
3000 miles away. So out came the
entire studio in less than 24 hours,
and they arrived east after three
days' travelling.
Meeting back -to- the -roots engineers on the West Coast is a growing
pastime. Elliot Mazer doesn't have
much doubt. 'There isn't a Dolby
on this session. We used to have
clients coming in with Dbx and
Dolby and all that stuff. I don't
want it. Now: there's hardly any
outboard stuff going on this session
-no limiters or anything like that.
Automation? No, I've been through
all that. I did the first automated
record.
'I want to hear what's going on
and for as little as possible to get
in the way. Here, for example, I'm
using everything straight through
except these, er, six with eq. And
some of that's precaution like this
700 Hz ring on the bass drum
coming up the toms. With a guitar
what do you
sound like that
do? It's coming straight out of his
amp, and you've got to relate to
the live sound.'
Perhaps the mobile beginnings
explain Mazer's devotion to
reliability. Again: 'I prefer to have
two of everything. We have two
MM- 1000s with adjacent serial
numbers, for example. When those
were on order and going through
the factory, I was down there talking to them; that's such a lot of
money that you have to treat each
one like a custom purchase. And
since we have two 16 tracks, one
can deputise for the other; but we
can still run 30 track if we want to,
with little problem. Even then you
only need one machine most of
the time, for when you get to 13
or 14 tracks full on the first two inch then you jump the time code
on to another and work with a B
copy. And these transports are
good for 14 in reels -and that
there is a power boost for getting
up speed at the start of a reel (I
don't like one mil tape). When
you're spooling it can take some
time to get going.
And those
Ampexes are two years old.
They've travelled 100 000 miles.
...
40
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Telephone Blackwood 3771 Telex 49135
39
II WORK
One time in Toronto when we
arrived it was 20 below. So we
switched them on; gave them half
an hour's warm -up. After that they
were within
dB or so.
'Other tape machines? Like
said, two of everything: three
stereos, two monos and a four
track in the closet.' One of the
monos (an elderly Studer) is in
constant use on recording sessions
as a logging machine off the
monitor mix. to save running the
Ampex while the band is putting
together a tune. Such as happened
the sunny afternoon in spring I
was there, with an unmentionable
band of quasi -superstars taking as
long as anyone does in a $115 -anhour rehearsal room to arrange
their songs. So after a steady hour
or so of sound getting -together, all
retire to the guest suite at the back
of the cavernous 7 x 8m studio,
with what appears to be a horsehair
sofa restoring the Wcst Coast
balance with Warner Bros facilities.
'You need a big control room for
social reasons, quite apart from
this one being pretty live. When
the Dead come in. their entourage
averages 15.
And that circle is
pretty busy at the moment, probably more than at any time in the
last ten years.'
The studio itself is live, approximately 15 x 16 x 6 metres, with
concrete floor and two and a half
tons of redwood.
A particular
favourite among the mic complement is the Schoeps, not a common
sight in North America. Although
there was quite a lot of baffling
j
that afternoon, other Mazer productions have regressed happily,
like the latest Rab Noakes album
which used direct stereo recording
on three or four tracks. 'No, I
can't remember which ones ... the
ones that sound best.'
Another
recent album was Andy Fairweather
Low's Spider firing, which had no
live two tracks but one live multitrack. 'Some were done live, but
then added to -same old story.'
With the live, helpful studio,
Mazer reckons its straightforward
to tackle straight stereo. It's also
used as an echo chamber, using a
basic C24 in the centre of the room
which is driven via the monitor
work, or the Altec 604s which are Davies has joined Pye Stu.lios,
there for any visiting engineer who where manager Howard Barrow
may want them. 'But with a good says he will be helping Pye take
engineer we usually find a similar some of the workload off the cutting
sound coming out of this studio. room staff. 'We want someone to
With only one exception I can think cut, copy and handle clients,' he
of. When Steve Barncard comes, said. When asked what Davies's
he gets a different sound
it's a title would be, he said: 'We don't
good sound. but it's different and have titles here, he'll be part of
it's difficult to say why.'
the organisation. He'll be a cog
Like the speakers, the Neve in the wheel and we hope he'll
console has come in for some come up with the goods.' On past
tinkering. A standard 20/8 with form there shouldn't be much
16 track monitoring, there is now doubt about that.
provision for up to 34 inputs,
Meanwhile Pye engineer Bob
'enough for years yet'.
Other Harper joined Aisling Studios in
changes include the splitting of Dublin on July 7. The studio is
channel and monitor cue pairs to run by composer Philip Green.
give four independent circuits in Harper was one of the resident
place of two. Exterior to the desk, engineers on the Pye mobile before
the studio has an unusual number it was sold to the Manor last year.
of access points. Thus: 'If a client
John Dwyer
asks for something strange, a more
standard studio might think it
outlandish but we can do it,
Revamped Stones mobile
because we have that flexibility
HAVING SET UP a mobile at a time
built in. One day I came in after when that
meant a man with a
a Dead session and thought someNagra, the Stones recently decided
one had stolen all the mic cords
to give their 16 track facility a
for some reason. I'd had 47 the facelift.
This amounted to more
previous day and now there weren't
than just a coat of paint; the interany in the studio. Then I saw the
ior and apparatus has been changed
control room.
All the tape to accommodate
an extra eight
machines and their Moogs and
tracks of recording capability.
stuff were all joined up, patches
This
running from one side of the room 3M70 brings the total number of
machines permanently fitted
to another, across the console. It
within the vehicle to three
24,
was a wild session, but we could
16 and a two track.
The Helios
cope with it.'
desk has been extended by six
At the moment, business is so channels,
bringing the total to 26.
brisk that they're turning it away.
Mick McKenna, the resident enginRecent work has included Michael
eer, says that even 26 channels
d'Abo, Joe Cocker, Don Preston
for Shelter, Lenny Williams's solo aren't enough; he has now extended
the desk by a further six 'mini
work outside Tower of Power, and
channels'. These offer the basic
a co- production is forthcoming
requirements but no more; there's
with Merle Saunders ('he's a sort
nothing fancy like equalisation etc.
of friend of the studio'). Last 'These
channels are fine for things
autumn, the Dead recorded a
like brass or the roar of the crowd.'
mammoth film soundtrack, due for
That other function of recording
remix this summer and for eventual
complexity. the patch bay, has also
release in 1976 as a three- or four been extended. On the subject of
record set.
Remote work has
input channels, it is interesting to
included Neil Young, Frankie
Miller, the Allmans, and Chicago. note that Mick McKenna incorAnd in another world, the National porated patch space for up to 44
mic lines with only 32 inputs to
SO of Washington and Haydrt s
the desk. He explains: 'It's useful
Mass in Time of War. The kids
who knocked on the door and Exterior of Stones mobile
made it through reception realh
knew who to touch for a donation
to the school
'oh well, so much
for the profits this week'.
...
-a
...
Michael Thorne
sends.
Monitoring is typically via two
pairs of JBL 4325s, modified into
Mazer specials with
a
different
crossover and a super tweeter,
which sit politely on a pair of road
boxes. These are used for quad
when required, although assurance
was that mono was the favourite
sound of them all.
Others are
available as required, such as the
Klipsch units often used for mobile
40
Moving
OUR APPLE REPORT (in July STUDIO
SOUND, p44) mentioned a mysterious
organisation called Aboko, which
should have read Abkco, of course:
and though it was our fault we
think John Dwyer ought to get a
new typewriter.
We've since learned that former
Apple studio manager Malcolm
STUDIO SOUND, OCTOBER
1975
if you
are doing a gig where three
bands are playing. You can set up
mics for all three without having
to mess about
all you do is
re-patch.' He plans to set up even
more spare mic lines.
Other things have changed.
Altec 604 8G monitors replace the
previous Tannoys: 'not enough air
in the truck for them to work
properly'.
The sound-bending
devices have been tidied up. Before,
the Pultec, Kepex, Audio and
Design, Urei, Altec, EMT Countryman and Binson compressors/
limiters / phasers /equalisers /stereo
plates and drum echo were manhandled in and out of the truck as
they were required. Mick: 'It was
a very Micky Mouse affair'. Everything now has a place in the truck,
and as a result the rear end of the
truck became rather overloaded,
resulting in sagging springs. These
have been beefed up to cope.
Why did the updating work
become necessary? It would seem
to be reflecting the current trend
in land -based recording studios.
Mick: 'People ring up and ask if
you can do a gig and then ask.
almost as an afterthought: By the
way, are you 24 track ?'. The truck
has been equipped so that it can
do any type of work. If needs must,
an Ampex ÁG440 can be rolled
on board specifically for eight track
...
although Mick would
rather 'hunt around' for an eight
track head block to cut out the
aggro involved in hooking in yet
another machine. In any event,
there's not much call for this type
of recording because of the small
price differential between recording
rates. It's not the recording tape
that costs the money, it's the hassle
of setting up.
What sort of work has been done
recently? Obviously, the Stones
recording their new album in
Holland. Some of the other people
include the Who, Led Zeppelin,
Paul McCartney and about three
column inches of the showbiz
sessions,
Who's Who.
Frank Ogden
modular series mixing console
U1IIIAAI
KNICK PEAK PROGRAMME
METER AD 26V
Hugh Ford
MANUFACTURERS' SPECIFICATION
Indicator range : -50 to +5 dB and -70 to -15 dB,
switching by keys.
Input reference: +6 dBm, calibrated +1% internal
adjustment within +1 dB possible.
Frequency response: +0.1 dB. -0.5 dB.
(40 Hz to 15 kHz)
Input impedance: > 10 k12 symmetrical floating.
Measuring error :< f0.1 dB in range +5 to -25
dB. <±0.5 dB in range
in range -50to -70 dB.
-25 to -50
dB.
< ±1.0
dB
Integration time (90;'-x): 10 ms.
Indication delay: <1 ms.
Overshoot: <0.1 dB.
Polarity reversal error: <0.5 dB,
Working temperature range: -20 to -{ -55'C.
Power supply: 24V, +4 -2V
300 mA
Connections: multipeg Tuchel T 2700.
Special instrument versions (on request): differ(r.l.
ent measuring ranges, comparator outputs, illuminated switching key and different switched intervals,
different rise and return times.
Price: £450 + VAT.
Manufacturers: Knick Elektronische Messgerate,
D -1 Berlin 37, Beuckestrasse 22, Germany.
UK Agents: Dyer Audio Systems, Unit 3, 164 High
Street, Barnet, Hertfordshire.
THE NAME KNICK will mean little to most
readers because it is a relative newcomer to
the audio business, and has specialised in the
past in the general electronics instrumentation
business. Knick now manufacture a range of
light beam type programme meters using light
emitting diode indicators in conjunction with
some rather clever electronics; the active
elements of these, with the exception of one
transistor, are contained in integrated circuits.
The type AD 26V meter reviewed here is
similar in design to the other meters in the
Knick range which comprises meters for
horizontal or vertical mounting with either 20
or 26 light emitting diode indicators and a
miniature meter with only three step indicators.
As its part number implies, the type AD 26V
incorporates some 26 indication steps in a
vertical array. The lamps are arranged in 1 dB
steps between the maximum indication of +5
dB and -9 dB, from when the array is in 3 dB
steps to -30 dB and then in 5 dB steps to the
minimum indication of -50 dB. This arrangement gives maximum effective resolution where
it is required about the overload point of
equipment and the change between green and
red indicators about the 0 dB indication gives
an instant warning of potential overload
conditions.
In addition to the basic scale range of +5 dB
to -50 dB, the meter sensitivity can be
increased by 20 dB by means of a miniature
locking pushbutton on the front panel, the
42
STUDIO SOUND, OCTOBER 1975
range becoming -15 dB to -70 dB when this
button is pressed. Adjacent to the indicator
lamp array there are calibrations in terms of
percentage modulation on the left, and dB on
the right, both calibrations being clear and
uncluttered. In practical use with speech or
music, there is no need to refer to the calibrations as the length of the light emitting diode
display gives a very clear indication of level,
and any overload above the 0 dB point is
instantly apparent when the display changes in
colour from green to red. However, for line up
purposes, the calibration points have been carefully chosen and include an extra marking at
the commonly required 35 per cent modulation
point.
The internal and external standard of
construction of the Knick meter is first class,
the unit using high quality components
throughout. Two printed circuit boards give
good accessibility to the components, one
board housing the meter drive circuitry and
the other all the light emitting diodes and their
associated drive circuitry. The internal layout
is so tidy that the only wires used in the construction of the meter are the connections to
the input balancing transformer!
Five preset controls are incorporated in the
meter. Two of these may be classed as operational controls, as they select the sensitivity
and the release time, the latter being variable
over the range 750 ms to 1.5s as standard.
The remaining controls do not effect the law
of the meter (as is so common) but purely
provide for setting the stabilised power supply
voltage, input amplifier balance and finally to
compensate for the input offset of one integrated circuit.
Principle of operation
The Knick meter dispenses with the conventional logarithmic amplifier and also dispenses
with the conventional methods of determining
the time constants of the meter, both of which
are the common sources of shortcomings with
many current types of programme meter.
The input to the meter is fed to an input
transformer, the secondary of which is centre
tapped with each half of the secondary winding
feeding a chopping amplifier, thus proving
two positive half wave outputs corresponding
44
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Presenting the successor to the series 2
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6 channels each with dual impedance input, input gain control,
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battery use.)
Price £294
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exc. VAT and DELIVERY.
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Tel: Windsor 51056 7 (trade enquiries welcomed).
43
IN
KNICK AD 26V
FIG. 1
to the negative and positive halves of the input
waveform. Fig. 1 shows the clever part which
follows: the output from the chopper amplifiers
is fed to two amplifier /rectifier combinations
which attempt to charge to storage components rc, the voltage on which is fed back to the
negative inputs of the amplifier /rectifiers thus
giving an extremely fast integration time.
However, a further element is included in the
feedback loop, which I have named the 'active
time constant' and it is this element in the
feedback loop which controls the integration
time, with the element rc only controlling the
release time. It is therefore possible to control
independently the integration and release times
over a large range.
Having produced a dc voltage proportional
to the quasi -peak input voltage it is then
necessary to manipulate this dc level to drive
the logarithmic array of indicator lamps, and
it is here that Knick has been clever again.
Each light emitting diode lamp is driven by
a voltage comparator integrated circuit. One
input of each integrated circuit is connected to
the dc output from the rectifier combination,
and the second input of each voltage comparator is connected to a tap on a potentiometer
chain which is fed by a stabilised dc source.
By careful selection of the taps on the potentiometer chain each individual indicator can be
arranged to be activated at any desired input
voltage
logarithmic series of potentiometer
chain taps gives a logarithmic relation between
the indicators.
-a
Measured performance
Measurements on the Knick instrument
were done on the understanding that the
review sample was set to the requirements of
the DIN standard 45 406 Peak Programme
Meter for Electroacoustic Wide Band Transmission' and also to the requirements of the
Institut für Rundfunktechnik (IRT) standard
which has additional requirements for light
beam type meters. As has been mentioned, it
is a simple matter to achieve alternative time
constants, and Knick do intend to produce
meters to other standards.
Initial attention was directed towards the
absolute and relative accuracies of the indications. The 0 dB indicator in the display was
found to just illuminate when the 1 kHz input
rose to -1 -6.03 dBm, a creditable figure where
the specification is +6 dBm +0.09 dB.
Similarly, the accuracy between indicated steps
was within a creditable 0.06 dB over the range
of indications +5 dB to -18 dB, below which
the errors progressively increased but remained
within the specified limits. The additional
error introduced by using the optional extra
20 dB gain was minimal at 0.1 dB.
The measured frequency response of the
overall meter was within +0 -0.3 dB from
20 Hz to 10 kHz, falling to -0.5 dB at 15 kHz
and -2.4 dB at 20 kHz. The response at 40 kHz
was -21 dB which is perhaps rather sensitive
for some applications, and only just within
the DIN standard.
The next, and very important matter, is the
unit's performance when tone bursts of various
types are applied. In order to save me much
trouble Knick was kind enough to lend me a
44
STUDIO SOUND, OCTOBER
1975
THE RECTIFIERS + TIME CONSTANTS
ACTIVE
TIME
14
CONSTANT
FROM
INPUT
CHOPPER
O.C. OUTPUT
AMPLIFIERS
Indication
ms burst of 1 kHz
3ms burst of 1 kHz
Time to 99 °, indication
-1.0 dB
Release time
0.5 ms burst of
1563 ms
10
burst of
10
10
0.5 ms
-4.0 dB
17
ms
kHz every 500 ms
Maximum indication -7.0 dB
Minimum indication -14.0 dB
kHz every 1250 ms
Maximum indication -9.0 dB
Minimum indication -30 dB
special testgear that it has developed for
measuring light beam type meters -this corn prises a number of photoelectric detectors
feeding a combination of gating circuits so
that the time between various indications can
be directly measured with timer /counters.
The above figures were obtained, which are
related to the DIN and IRT requirements.
From the above it is to be seen that the
'ballistics' of the Knick instrument are generally
well within the requirements of both the DIN
and the IRT requirements. Furthermore,
because the 'movement' is not of a mechanical
nature the various requirements for overshoot
and undershoot do not even apply. The final
points of interest are the input impedance and
the power requirements for the unit, and the
dc output connection which is available at the
rear panel socket.
Measurement of the input impedance showed
it to be substantially constant at 15k ohms,
which is ideal for normal usage. The dc output
gave 6.69V corresponding to 0 dB indication
from a source impedance of 495 ohms. The
residual dc output with the input shorted was
less than 4 mV (corresponding to -64 dB
indication) even when the +20 dB gain switch
was activated.
Changing the nominal 24V dc power input
over the specified range 22V to 28V made little
difference to the instrument's performance, but
at the lower limit there was a 0.13 dB shift in
the sensitivity for 0 dB indication. The steady
DIN
<1+0.5 dB
<4±1.0 dB
<300 ms
IRT
-1 s0.2 dB
-4±1.0 dB
<200 ms
1500±200 ms
-7.5+1.0 dB
-14+1.0 dB
-811
dB
-29 ?,2 dB
state power requirement never exceeded 200 mA
when operating on steady tones or programme
material.
Summary
The measurements outlined in this review
and also many other measurements which
were done on this Knick ppm, failed to find
any shortcomings in its performance, and
indeed confirmed that the performance was
generally far better than either the manufacturer's specification and the DIN and IRT
standards for programme meters. Furthermore,
the standard of construction is very good in
both the electronic and the mechanical departments.
Being myself used to reading mechanical
movements such as the conventional ppm and
(under duress) VU meters, a light beam
instrument is at first rather strange. However,
after very little use I was most impressed with
the readability of the Knick instrument and
found it most relaxing to use. I cannot,
however, vouch for the ergonomics of a
multiple meter display.
Other advantages of the Knick instrument
are the large dynamic ranges over which it
gives useful indications, and also the instant
warning by the red indicators when zero level
is exceeded. Unfortunately there is a price to
be paid for all this convenience and at over
£450 it is no cheap instrument.
has a. heartofgold
Synonymous with the world's finest
reverberation system is the name EMT
and their latest model 240 has the Midas
touch
An electrolytically produced gold
foil only 12 inches square lies at the heart
of this unit which ensures constant
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range, no flutter echo repeats,
minimum dispersion and smooth decay.
Easily transportable the 240 weighs
a mere 67kg and is isolated against shock,
vibration, ambient noise; it is ideally
suited to O.B. use with no need for
recalibration.
..
DATA
:
Reverberation time at 500 Hz
Variation of reverb time is effected
by a dampir:g plate which is varied
in its distance from the reverb foil.
min. 0.8s
_-
max. 5e
Density of resonances
Maximum ambient noise level
Frequency response from 40 Hz.. 15 kHz
relative to standard curve:
`otel harmonic distortion at kHz and max. output
:
;
F.W.O.
.3 /Hz
2 dB
0.5%
:
. 5.5 dB
Bauch Limited
49 Theobald Street, Boreham Wood,.
Hertfordshire ,WD6 4RZ
Tel 01953 0091 Telex :27502
0.5s
80 phon
1
S:gnal to nose ratio (unweighted)
0.2s
Audio
Test Set
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The B Series (Professional) amplifiers feature single power supplies suitable for
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£210 00
The above prices are list and exclusive of VAT.
TURNER ELECTRONIC INDUSTRIES LTD
175 Uxbridge Road, London W7 3TH
Tel.
8472
E900
drift
Sweep Equaliser
erasure
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Send for leaflet RTS2
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Telephone: Burnham 062 86 62511 Telex: 847297
FERI{OGRAPH
A member of the Wilmot Breeden group
46
STUDIO SOUND, OCTOBER
1975
AUDIO
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CARDINGTON 404
(ST,D, 02303)
47
REVOX A700
Hugh Ford
MANUFACTURER'S SPECIFICATION
All figures quoted are minimum performance values
as measured with Revox 601 tape (type LOW NO /SE/
HIGH OUTPUT), normally exceeded by all units.
Tape speed: 38 cm /s, 19 cm /s, and 9.5 cm /s;
maximum deviation from nominal +0 1" (measured
with 38 pm long- playing tape).
Tape slip: not exceeding 0'1';
Weighted peak flutter:
at 38 cm /s less than 0.06°,;;
at 19 cm /s less than 0089,
at 9.5 cm /s less than 0.1 ",
measured in accordance with IEEE Std 193 -1971
(consistent with ANSI S4.3 1972 and DIN 45 507).
Timer: read -out in minutes and seconds (4 digits),
real -time indications for 19 cm /s tape speed.
Accuracy 0.5 %.
Tape -reel dimensions: up to 267 mm outside diameter with automatic tension change down to a
minimum hub diameter of 38 mm.
Tape tensions: electronically regulated during all
operating modes, including stop sequence.
Frequency response via tape:
38 cm /s 30 Hz to 22 kHz +2/ -3 dB
50 Hz to 18 kHz +1 .5 dB
cm /s 30 Hz to 20 kHz +21 -3 dB
50 Hz to 15 kHz ±1.5 dB
9.5 cm/s 30 Hz to 16 kHz -, 2/ -3 dB
19
50 Hzto10 kHz +15dB
Equalisation: as per NAB standard.
Peak recording level: 514 nW /m (corresponds to
+6 vu).
Level indication: vu -meter as per ASA plus
optical peak level indication.
Overload indication: trigger level: +6 vu
(514 nW /m). Response time: approximately 10 ms.
Storage time: approximately 0.2s.
Distortion measured via tape at 1 kHz:
peak level
6 vu
operating level
(514 nW /m)
0 vu
38 and 19 cm /s: less than 2°
less than 0 6
9.5 cm /s
less than 3°-;;
less than 1",
4+
Signal -to -noise ratio: weighted
as per ASA 'A'
measured via tape and referred to peak recording
level (--6 vu):
38 cm /s better than 65 dB.
19 cm /s better than 66 dB.
9.5 cm /s better than 63 dB.
Crosstalk at 1 kHz: mono better than 60 dB.
Stereo better than 45 dB.
Inputs: 2 x microphone stereo, balanced 50
600
ohm, position 'low': 0.15 mV /6k ohm, position 'high':
1.8 mV /6k ohm.
x phono stereo, magnetic equalisation RIAA
2.5 mV /50k ohm.
x Radio stereo 3 mV /33k ohm.
2 x auxiliary stereo, 40 mV/100k ohm.
All inputs have an overload margin of 40 dB.
Outputs: output level from a peak recording level
at +6 vu (514 nW /m):
'line' A and B 1.55V from 5k ohm source.
x radio (DIN) 0.775V from 10k ohm source.
2 x headphone: max 4.9V from 100 ohm source.
x power amplifier: max 3.1V from 100 ohm source,
including remote mains switching for A722/Á724.
Tone control: bass L8 dB at 80 Hz in 2 dB steps.
Treble i8 dB at 8 kHz in 2 dB steps.
Semi -conductor complement: 19 integrated
circuits. 2 Isi circuits. 92 transistors. 92 diodes. 7
full -wave rectifiers.
Power requirements: voltage selector for 110 to
220V, 50 to 60 Hz operation without need for conversion. Consumption: maximum 130W.
...
1
1
1
1
Dimensions -cabinet without spools:
492 mm x 175 mm -with 267 mm
522 mm x 2065 mm.
483
mm
spools: 539 mm
x
x
Price UK: £735 + VAT (Recommended Retail).
US: $1800.
Manufacturer: Will i Studer, CH -8105 RegensdorfZurich, Switzerland.
UK agent: C & E Hammond & Co Ltd, Lamb
House, Church Street, Chiswick, London W4.
US agent: Revox Corporation, 155 Michael
Drive, Syosset, NY 11791.
FOR MANY YEARS the name `Revox' has
been associated with high quality recorders in
the professional /semi -professional and better
endowed domestic applications.
For some
reason Revox have seen little competition in
the field; while others have designed recorders
to compete with Revox, their end products
have either been too expensive or lacking in the
sound construction and good long-term performance that is associated with the Revox
trademark.
While I do not know the numbers of Revox
type 77s sold, considerable confidence in the
sales of the new type A700 is confirmed by the
fact that the pricing of the machine is based
on 100 000 units and that the development of
the specialised integrated circuits has probably
cost £20 000, let alone the other development
costs. With Revox working on such a large scale production, it is of course difficult for
newcomers to compete in this rather specialised
market, and with a few exceptions the following
review shows that the type A700 is indeed a
first -class recorder.
Tape transport
The basis of the tape transport is a flanged
alloy diecasting which is machined for the
attachment of the three motors and the headblock, itself a separate diecasting. The remainder of the unit is in the form of a cadmiumplated steel chassis to which is attached the
electronic parts and the heavy mains transformer which is, of course, better kept off the
main diecasting.
Constant tension winding is obtained by
servo control of the two outer -rotor type
spooling motors, with the resulting capability
of handling either 267 mm NAB spools or ciné
centred spools; however, NAB adaptors are
not supplied with the recorder. Tension control
signals are derived from tension arms adjacent
to each spool, the tension arms being spring loaded with their position sensed by a variable
transformer which electrically controls the
500-
48
STUDIO SOUND, OCTOBER 1975
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REVOX A700
operates in the trailing position by a solenoid operated arm which also manipulates the
spooling motor torque. Proceeding towards hinged replay head hum screen.
the headblock, there are two large diameter
All the tape transport drive functions are
idlers, the right -hand one driving the tape
electrically interlocked, and tape tension is even
timer which is calibrated in minutes and controlled in the start and stop modes with a
seconds at a tape speed of 19 cm /s, and is also
resulting smooth operation without any
used to detect tape motion -again using an rf tendency to throw loops or other untoward
variable transformer technique.
habits. It is quite possible to go directly from
The headblock casting forms a plug -in unit fast wind to record without disaster -the tape
with space for four heads, the normal comple- stops from fast wind, is lowered on to the
ment being the erase, record and replay heads. heads and proceeds in the record mode!
Azimuth adjustment is really sound, with very
However, not all is perfect; one shortcoming
positive head location. The tape guidance has
is that, in spite of the fact that tape motion is
been given great thought; there are four detected and the tape end is optically detected,
adjustable spring -loaded guides on the head - when the tape comes to a finish the recorder
block. 1 am, however, a little worried about takes a considerable time to stop the take -up
the wear properties of the guides, which appear spool with the result that tape can fly all over
to be unplated brass.
the place. This defect is caused by too much
As with all respectable recorders, a flutter
inertia and too little friction around the tape
roller is included to reduce friction noise (scrape motion sensing roller. A further matter is that,
flutter), but 1 was surprised to find that a fixed
in my opinion, the fast wind modes are too
guide is included between the flutter roller and fast, such that even 3M type 207 with its matt
the record and replay heads. The capstan
back does not give a very clean wind on the
motor is a special servo motor which is phase take -up spool.
locked to a crystal oscillator, offering constant
All function controls are illuminated pushspeed irrespective of the incoming mains
buttons, the current function(s) showing a
frequency at the three tape speeds of 38 cm /s, white light in the case of non -record
functions
19 cm /s and 9.5 cm/s. However, when it is
and a red light in the case of record functions.
required to operate at different speeds an The three tape speed selection buttons are
only
external frequency may be used as a reference.
illuminated when the selected tape speed has
The capstan is of large diameter, thus easing
been attained, providing a safety factor when
mechanical tolerances.
The pinch roller
changing speed. Other than the normal tape
A professional
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That's the way it is with Waters professional audio attenuators.
They feature
glass -hard MystR® conductive plastic elements and slip rings as well as precious
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Result smooth, quiet, long -life performance under the most grueling
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You'll find Waters complete line of professional audio controls meets
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-
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Longfellow Center, Wayland MA
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U.S.A. 617 -358-2777
movement buttons, there is a non- locking
`pause' button which operates in any mode,
including fast wind and two further control
modes. One of these does a fast rewind when
pressed and reverts to play when released
very useful for editing; the other button
provides an `auto' function whereby the recorder
optically senses a spliced `window' at the ends
of the tape. When the end is reached, it rewinds
and reverts to its original play or record mode
at the beginning of the tape.
Access to the heads for editing is quite good,
and certainly there is no problem in gaining
proper access for cleaning and de- gaussing.
However, it is not possible to listen in the fast
wind modes where the tape is removed from
the heads by two solenoid -operated guides.
Rock and roll operation is possible in the stop
mode.
-
Electronics
All the electronic components are mounted
on printed boards, most of which are identified
with component references as an ease to
servicing. The general arrangement is that
small boards plug into a mother board, which
contains a number of components; however,
access to these and other components is excellent and the many integrated circuits plug into
sockets as a further aid to servicing. The
overall standard of construction is excellent
and the power supplies, which can be operated
from all the common mains voltages and
frequencies, are protected by some eight
identified fuses. One small irritation is that
the mains lead is not of the plug -in type;
however, plenty of storage space is provided
for it and its plug.
On the record side comprehensive mixing
facilities are provided, selection of stereo inputs
being by means of two input selector switches,
each of which has two (left and right) slider-type
level controls. One selector has positions for
microphones of high or low sensitivity, RIAA
phono, radio or auxiliary inputs, while the
second selector provides for further microphones of high or low sensitivity, multiplay/
echo, an auxiliary input and an off position.
The microphone inputs are balanced 6.35 mm
jack sockets on the front panel and, with the
exception of the radio input which is a five-pole
DIN socket, the remaining rear panel inputs
are phono sockets. A further slider control is
provided for setting master level, recording on
either or both of the half tracks which are
selected by illuminated pushbuttons.
Two vu meters are provided for monitoring
level in the before or after tape conditions and
are also fitted with peak indicator lights which
have a relatively fast response. I am, however,
surprised that Revox have not gone to peak
type meters.
The entire replay section is switched to
before or after tape by the same switch as the
level meters, and can also be switched to the
four modes of operation- stereo, left, right or
mono. However, of the two available line
outputs, one is before the mode switch and the
other after. These line output phono sockets
and the DIN type record /play socket are at
fixed level and occur before the tone control
circuits which affect the remaining outputs.
These remaining outputs comprise a power
52
50
STUDIO SOUND, OCTOBER
1975
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51
REVOX A700
=====.
FIG.1
amplifier output in the form of a DIN socket
and two headphone outputs in the form of
stereo jack sockets on the front panel; one of
these disenables the power amplifier output
when the phones are inserted. These outputs
are controlled by a slider gain control and are
affected by the bass and treble controls which
take the form of rotary switches.
In addition to the audio facilities, the power
amplifier output supplies a 20V dc line for
switching the mains in the auxiliary power
amplifiers made by Revox. As this socket is a
standard 180° DIN socket it follows that some
caution is required not to attach other equipment to the 20V dc line. Further sockets are
provided for remote control, and for external
speed control; a dummy socket being fitted to
the review machine for the future addition of
slide synchronisation.
Perhaps unfortunately, there is no provision
for the addition of noise reduction systems,
but such an addition should not be difficult as
a customer modification.
Replay performance
Checking of the replay equalisation to the
NAB standard was accomplished by means of
DIN calibration tapes manufactured by BASF
which are, themselves, subject to a tolerance
of ±1 dB at high frequencies. It is therefore
most encouraging to report that the Revox
performance was within ±0.8 dB from 40 Hz
to 18 kHz at a tape speed of 38 cm/s and ±1.2
dB from 40 Hz to 18 kHz at 19 cm /s or from
40 Hz to 16 kHz at 9.5 cm /s. Clearly the
machine had been most carefully aligned, and
this was confirmed by checking azimuth in
terms of relative phase between tracks.
The signal -to -noise performance in terms of
reference level to noise is also excellent as is
to be seen from the following figures which
show the performance of the replay amplifier
system without tape but with all motors
running (see table l).
On the other end of the scale, it was found
that amplifier clipping, at 1 kHz at a nominal
tape speed of 38 cm/s, did not occur until the
fluxivity at the replay head was increased to
some +15 dB above 320 nW /m, which allows
in the order of 5 dB margin for any current
tape types.
Record replay performance
As with the replay only frequency response,
the record /replay response with 3M type 207
magnetic tape was really excellent. Fig. 1 shows
that the overall response at 38 cm/s is within
±1.3 dB from 20 Hz to 20 kHz including the
minor bass boost at 30 Hz which is probably
due to head polepiece effects. It should also
be noted that the balance between the two
channels is really excellent. The general pattern of the response at 38 cm /s was followed
at two lower tape speeds as shown by the
following (see table 2).
The following table shows the reference level
to noise ratio for 3M type 207 tape in its bulk
erased form, and when it has been erased and
recorded with bias by the machine with all
inputs shut (see table 3).
Comparison of the above table with the
replay only figures shows that there is a
STUDIO SOUND, OCTOBER 1975
52
_=_'-__EEEEI
REVOX A700
RECORD /REPLAY
RESPONSE
313cm
/s
-MM:EEE
CM::::
CC=....
-IMM::::
-=_9EEE
1CM::::.C:EEE
M- =ra1.ñ:,r_____..-...1
LEVEL:- 50dB /320nWb /m
PEN SPEED
:
200mm /S
IM
-MM
PAPER SPEED: 3mm /S
:
M::::
CCM
-MM
20
50
MMiM:Miiiá".
1=11111
..
MC111IM...
MCCCM:::: MCCMM::::
-=1
CMM::..
-M::::
MCC:CM::::
10
11,
___:'::_
'::
CCM:...
:MM:.
:MM...
2d8
100
500
200
FREQUENCY
TABLE
Tape speed
_-...
:::EE
CCCM
-...
_Cr...
..-t...:r
-MC
-=..
__.:_
_
MN
:M
::
C
- M ::
WITH 311207
CHANNELS ALTERNATELY SWITCHED
ZERO
----'...
_-r.r.:::
1.=.O2::::
1000
CCM
2K
5K
EE
20K
10K
IN Hz
1
Reference level
Unweighted
20 Hz /20 kHz
320 nW /m*
320 nW /m*
250 nW /m
38 cm /s
19 cm /s
Reference level to noise
CCIR weighted ref 1 kHz
RMS
rms meter DIN peak meter
74 0 dB(A)
68.6 dB
63.6 dB
73.4 dB(A)
680 dB
63.3 dB
65 4 dB(A)
61.0 dB
55.5 dB
'A' Weighted
65 8 dB
64.5 dB
9.5 cm /s
58.8 dB
Figures are average of both channels.
*Add 4.1 dB for a reference level of 514 nW /m.
TABLE 2
Tape speed
38 cm /s
19 cm/s
9.5 cm /s
TABLE
0.5 dB
L20dB20Hzto20kHz
iO4dB
=2.0 dB
+1.0
20 Hz to 18 kHz
dB
3
Tape speed
Reference level
'A' Weighted
rms
cm /s
Bulk Erased
Machine Erased
320 nW /m`
cm /s
Bulk Erased
Machine Erased
320
38
19
Channel balance
worst case
Frequency response ref 1 kHz
worst case
z_L1-5dB20Hzto20kHz
Reference level to noise
CCIR Weighted ref 1 kHz
DIN peak meter
rms meter
67.1 dB(A)
63-2 dB(A)
60.4 dB
55.4 dB
55.9 dB
51.2 dB
67.7 dB(A)
64.2 dB(A)
59.7 dB
55.2 dB
54.7 dB
50.5 dB
nW/m*
250 nW /m
9.5 cm /s
61 8 dB(A)
54.7 dB
Bulk Erased
59.5 dB(A)
52-5 dB
Machine Erased
Figures are average of both channels, which were within close limits of each other.
*Add 4.1 dB for a reference level of 514 nW /m.
considerable margin between the inherent
machine replay noise and the noise from a
modern tape such as 3M type 207, it is however
felt that a small improvement is still possible
in the noise introduced by the record process.
Distortion at the above reference levels was
less than 0.8 % third harmonic at the two upper
tape speeds, and less than 1.0% third harmonic
at a tape speed of 9.5 cm /s. Three per cent
third harmonic distortion occurred at +5 dB
above reference level at the two higher tape
speeds and 7 dB above 250 nW /m at 9.5 cm /s.
Intermodulation distortion was measured at
a tape speed of 38 cm/s by the SMPTE method
using 50 Hz and 7 kHz tones in a 4:1 amplitude
49.9 dB
46.5 dB
ratio at the following equivalent peak sinewave
levels:
Record level
IM distortion
320 nWb /m
5.5 %
1 2%
less than 1.0%
-10
-20
dB
dB
While the figure at reference level demonstrates the shortcoming of the bass boost in
NAB equalisation, the figures at lower levels
Of
are good by tape recorder standards.
54
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53
REVOX A700
similar interest to intermodulation distortion
is the effect of friction noise (scrape flutter).
Fig. 2 is a narrow band analysis of a replayed
10 500 Hz tone that had been recorded at 38
cm /s. While flutter sidebands can be clearly
identified at approximately +10 Hz and
multiples thereof from the carrier frequency,
this performance is good in comparison to very
many recorders.
Of further interest is the phase relation
between the two stereo tracks; this property is
shown in fig. 3 which is an oscillogram of the
phase shift when recording and replaying a
10 kHz signal at 38 cm/s. This oscillogram,
which shows a maximum phase deviation of
+6°, was obtained by using a Bruel & Kjaer
2971 phasemeter which has a response time of
2400° /s at audio frequencies. It is interesting
to note that the periodicity of the phase shifts
may be correlated with the pinch roller
diameter.
The investigation into crosstalk performance
yielded very good results with the measured
record/replay crosstalk between channels being
below 70 dB at mid frequencies, including
head contour effects which remained below
53 dB at any audio frequency, 35 Hz being
the worst case.
Erasure performance was measured by
recording a
kHz tone at 38 cm /s at the
reference level of 320 nW /m, and then measuring the residual signal after a further pass over
the record and erase heads with the input
the resulting signal was reduced
faders shut
some 83 dB on the worst channel, the other
channel offering some 87 dB erasure -no
complaints in this department.
1
...
-
Wow, flutter and speed
Wow and flutter to the DIN weighted method
(as now agreed by the IEEE and ANSI) was
measured at the beginning, middle and end of
both 178 mm cine type spools and 267 mm
NAB spools at the three tape speeds. While
there was little variation of wow and flutter
within a spool, the initial measurements at the
tape speed of 38 cm /s were somewhat higher
than those shown in the following table, which
are average values:
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54
STUDIO SOUND, OCTOBER
1975
U.S.A.
Tape speed
38 cm /s
19
cm/s
9.5 cm/s
Spool type
Weighted wow and
flutter to DIN
NAB
0.025%
Cine 178 mm
NAB
Cine 178 mm
o04/
0.035%
0-05%
NAB
007%
Cine 178 mm
0.09%
These results which are well within specification are outstandingly good for this class of
recorder, and the initial measurements were
within specification. However, no reason was
found to explain the higher initial measurements which were consistent over a period of
time. The measurement of the tape speed
indicated the identical error of +0.3 % at all
speeds which is on the tolerance limit of the
calibration tape used; furthermore, the speed
variation from one end of a NAB reel to the
other was within +0.01%.
r
100H
FIG. 2
REVOX
A700
NARROW BAND
ANALYSIS OF FLUTTER
3.15Hz RESOLUTION
10500Hz
POT
TONE AT OVO
50dB
10dß
FIG. 3 Showing phase error L -R (maximum ± 6')
10 ms of an overload, and stayed on for 130 ms
thus easing readability.
::::
::::OCO::::
.:ö
..
::
--..::
M....
25
FIG.4
REVOX A700
TONE CONTROL
CHARACTERISTICS
20
...
r.:::::
Cï
::M....
0::::CC
::
MI=........
........
=
::C::::
::..
M....
::::_
0...
::::
1=1111=.ö
RMS
ZERO
LEVEL
POT:
50dB
PEN SPEED
OVO
200mm/5
ICM::::
:,,.1111..._
15
dB
MNIMIM....
-
smumum...-
11C1M::::
.111.t114i
M.711110111::..
10
_::::
=_::::
IMI=11M...
SIMIMIlla.7..
REGT
Summary
During the course of this review I have been
critical of any minor shortcomings of the
Revox A700 for the simple reason that this is
a very interesting machine which will, without
doubt, sell in great numbers; it is a very fine
machine for its price and thoroughly
recommended.
I would however suggest that the microphone
input impedances should be modified to reduce
the rather high noise level that results from
such a high input impedance and that some
attention should be paid to the zero level
settings of the vu meters.
.::
-_....
CC'.i
Gì'siii
lIMIC::::
C:::: CÇ
111M
7....1111101
=M....
IMIM...
111MIM....
0
0
20
50
CC:::1 /11....
...
::::
100
200
=MOM,
1000
500
FREQUENCY
Inputs and outputs
All the above performance figures were
measured between the line inputs and the line
outputs, the alternative facilities were therefore
investigated. So far as frequency response is
concerned, the microphone inputs to all intents
and purposes were flat from 100 Hz to 20 kHz,
but showed some roll -off in the bass with a
dB point at 35 Hz which is no bad thing.
On the other hand the phono input was within
10.5 dB of the RIAA equalisation curve from
20 Hz to 20 kHz.
While noise in the record section was
generally good, the microphone inputs were
rather excessively noisy, the equivalent input
noise being 113 dBm when loaded into 200
ohms-this figure could be considerably
improved.
The sensitivities and impedances of the
inputs and outputs were all checked and found
to be to specification, although some comment
is appropriate. Firstly, the input impedance
at the microphone input is effectively around
6k ohms which is far higher than is required
for 200 ohm microphones which are probably
the most common impedance. The measured
noise from the microphone inputs correlates
very closely with the unnecessarily high input
impedance, and the provision of an impedance
in the order of lk ohms would make a very
3
2K
5N
K
20k
IN Hz
substantial reduction in the noise from this
source.
Secondly, the impedance of the line outputs
at 4.4k ohms (as measured) is unduly high for
professional applications, and while the alternative headphones and power amplifier output
are available, they are after the level control
and tone controls.
On the subject of the tone controls, these are
seven -position rotary switches giving 2 dB steps
at 80 Hz and 10 kHz, the good characteristics
of which are shown in fig. 4, which shows the
response at alternate positions.
The level meters
While most manufacturers claim to fit vu
meters, inspection often reveals that the socalled meters are nothing like the ASA standard
meter -not so with Revox, the vu meters are
to the proper specification with average rectifiers and the correct rise time -the return time
is however measured at nearer 400 ms than the
recommended time which is close to 300 ms. I
am not however at all happy about the tape
flux level corresponding to 0 vu which was
found to be
dB relative to 320 nW /m which
only leaves a 6 dB margin between 0 vu and
3 % third harmonic distortion as opposed to
the NAB recommendation of 8/10 dB.
On the other hand the peak indicator lamps
operated at the 3% distortion point within
1
On the credit side there are many excellent
aspects of the machine; among which signalto -noise in the replay department, frequency
response, speed stability and wow and flutter
Furthermore, the
deserve special mention.
standard of both mechanical and electrical
construction are beyond reproach. In fact, the
two latter aspects of the machine put some
recorders costing very much more into disgrace.
56
0
AGONY COLUMN
1n the olden days, the engineer used to rule
his studio and the visiting producers with a
rod of iron; one gentleman of our acquaintance
was often known to turn out the lights of a
control room full of people when he wanted to
go home and they hadn't got the message when
he put on his coat. Nowadays, things are very
different.
The session was getting late. Too late for
doing anything constructive, so the engineer
thought. Suddenly, a small explosion and a
cloud of smoke from behind the racks, and the
faders came down. Sorry, the power supply's
gone. Oh well, nothing was happening anyway.
Thanks a lot, good night, nice working with
you.
Only things left to do for the tired engineer
were strip the studio, tidy up, and replace the
disc cutter swarf in the metal box, with the
fuse wire across it connected to the mains via
the little switch on the console . . .
55
FIELD TRIAL
REVOX A700
Angus McKenzie
ALTHOUGH THE Revox 77 series, the first
Revox transistorised tape machines, were
domestically orientated both in design and
facilities offered, many professional users have
found them extremely useful, and in particular
the high -speed version running at 19 and 38
cm /s.
The 700 series, on the other hand,
appears to be a semi -professional version of
what was basically designed as a professional
machine. The basic tape deck is being incorporated by Studer into a new professional tape
recorder, the A67, and so, although the 700
electronics are clearly designed for domestic
as well as professional use, they are designed
down from professional, rather than upwards
from domestic. The machine therefore contains
many very useful professional features, while
still incorporating a large number of facilities
demanded by the really keen amateur. I have
been using two Revox 700s for some considerable time, both professionally and in a domestic
environment, and while I find the domestic
input and output sockets extremely annoying
when making interconnections with professional equipment, matching can be achieved
by unbalancing balanced outputs from the
control desk to the machine, and connecting
back in to the control desk if necessary with
external I:I 600 ohm transformers, driving
these from the headphone sockets, or from the
line output phono sockets rewired internally
to the output of the headphone amplifier.
I definitely agree with Mr Ford's comment
in his review that the microphone transformer's
effective input impedance is much too high.
Many users would have to use 200 ohm
dynamic microphones such as the D202 plugged
straight into the microphone input jacks. To
check the subjective noise of the microphone
pre amplifier input circuitry, I compared this
setup on track one with a D202 microphone
plugged through my Calrec control desk,
whose line output was connected through the
auxiliary two input to track two. The recorder
was set to 38 cm /s, and a fairly high recording
level was chosen, with both channels peakirg
identically. The hiss level on track one was
noticeably higher than that on track two, but
the margin did not seem quite as great as I
might have expected from the measurements.
For most recordings the input noise would be
found satisfactory, but it would be sensible to
alter the sensitivity of the microphone input
by switching the primary impedance of the
microphone transformers rather than, or in
addition to, the gain round the integrated
circuit pre amplifier. I proved this point by
using an external 1:4 impedance ratio microphone transformer, thus driving the Revox
from an effective 800 ohm source instead of a
200 ohm one. An improvement of about 3 or
4 dB was audible. I also used high output
capacitance microphones straight into the
Revox, and on the low mic gain position found
that it was not possible to clip the input under
all reasonable circumstances, which even
included shouting fairly close to the
microphone.
I also compared the basic quality between
the direct microphone input and the microphone via the control desk, and I felt that
there was a trace of intermodulation distortion
produced in the Revox's microphone preamplifier which did not seem to be present on
the auxiliary two input from the control desk
signal. The difference however was fairly
marginal, as was the subjective frequency
response.
The input circuitry is arranged in pairs so
that input channels and 3 mix together to the
left channel, while inputs 2 and 4 mix to the
right. The controls mix with a virtual earth
circuit either to stereo or mono, the mixed
signal then controlled by a master record gain
control. If the master gain control was used
nearly flat out, with the channel gains brought
down, I noticed some hiss, and so care must
be taken not to use the master gain control
too high, unless a lot of gain is required, with
the input channel controls already flat out. I
must criticise the absence of pan pots which
should be provided on input channels 3 and 4;
the circuit would allow for their inclusion with
ease. The sliders of the channel gain controls
in the circuit feed through resistors to the
virtual earth point where the pan pots could
be inserted with outputs to both channels. If
this were done it would allow channels 3 and
4 to be panned anywhere, while channels 1
and 2 could be used for the overall stereo main
input. Furthermore, it would allow flutter
echo or line inputs to be mixed in at will for
special effects.
The RIAA phono input worked extremely
well when driven from a Shure V15 Mk3
cartridge, and the gain provided was more
than adequate to allow satisfactory dubbing
from disc to tape. Although I dislike the fivepin DIN standard, the socket provided, conventionally wired, worked extremely well. This
socket allows the recorder to be connected
directly to tuner amplifiers also having five -pin
DIN standards.
The tape monitor switch worked very well
with no audible plops on the tape when the
switch was changed continuously during
recording. The line output sockets, however,
are connected in such a way as to render many
of the replay facilities of the machine almost
useless to the average user. While one pair
is connected directly across the amplified
output of the a/b switch, the other pair follows
the stereo 1/r mono switch. The high output
impedance of 4.7k ohms was extremely irritating when the machine was used to drive
external A Dolby processing units, or alterna1
58
56
STUDIO SOUND, OCTOBER 1975
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Both are of compact construction using Neve 3000
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you should be thinking about in this of all years.
57
REVOX A700
tively, the tape monitor inputs of control desks
since the return level, loaded by the input
impedance of the external circuit, was lower
than the levels that would normally be sent to
the recorder from such equipment. The recorder is fitted with some excellently designed 2 dB
per step treble and bass controls, and also
replay gain slider controls for both channels.
Both monitor tone and gain controls drive only
the headphone sockets and a socket provided
to work with a Revox power amplifier. Hugh
Ford mentioned the potentially high current
voltages on the normal five-pin DIN socket
provided for the latter, and I actually fused the
dc circuits when I attempted to use the socket
after installing the machine, no manual then
being available. Revox should replace this
socket by a 270' one as soon as possible, so
that users will realise that the socket is non
standard.
The headphone sockets, driven from an
output amplifier, possess a very low source
impedance. 100 ohms resistors are connected
in series with the jack sockets to restrict the
current available into low impedance headphones. The voltage available from the headphone amplifier will allow 600 ohm line
transformers to be used at this point, which
can provide as high a level as is necessary to
drive professional equipment, even when
loaded by 600 ohms. There is also a reasonable
amount of gain in hand to bring under modulated tapes up to full studio levels at this
point.
Since I frequently use the 700 to drive Dolby
A deprocessing units, I checked the vu meter
calibration on Ampex, MRL and DIN reference tapes, and while I agree with Mr Ford's
measurements on the DIN, I found that the
meters were only under -reading by 1.5 dB or
so on the Ampex tape, but since the machine
supplied was an NAB model the error is not
so serious. I am more critical, however, of
the 1 dB difference in calibration between the
two replay channels, which should not have
been passed by quality control. I am nevertheless puzzled by the measured differences
between Ampex and DIN test tapes, not
agreeing with the theoretical values; this is
noticed on any machine used for comparison.
Although the tone control steps are useful, I
feel that it is a pity that two positions of the
treble control and one position on the bass
control could not have been used to obtain
DIN equalisation positions for the two higher
speeds. Step corrections having a shelf 3 dB
cut or boost from 3.5 kHz upwards would have
made a good compromise for this, and would
also give a useful presence boost or cut for
general purposes. A 3 dB boost at 50 Hz
extending to 5 dB at 31.5 Hz would give the
necessary bass correction. The existing tone
controls do not give anywhere near an adequate
standards conversion. A DIN version is also
available to special order, having both record
and replay equalisation permanently changed.
Most users will find the provision of separate
equalisation and bias controls for all three
speeds most useful, as I have done; I normally
have my machine set up for standard play tape
at 38 cm /s and 1p tape at the two lower speeds,
since standard play tape tends to drop out
58
STUDIO SOUND, OCTOBER 1975
more at lower speeds. I have noticed that any
such mixture of tape types allows unity gain
before and after tape to be achieved only at
one speed. An error of up to 2 dB can be
produced, and it would therefore be an
advantage to have separate record level pre -sets
for the 38 cm /s speed.
On almost all the earlier models of the 700
series that I have encountered a serious design
fault could cause clicks or short transient
splashes of an input programme to be recorded
when the record track buttons were up. This
fault was rapidly brought to the attention of
the importers. Studer produced some circuit
boards to overcome the problem. These can
be inserted in between some existing boards
and their holders, and fit very easily. The
specific machine reviewed by Mr Ford,
however, did not exhibit the described fault,
but neither did it have the extra boards, so I
must assume that Revox have very recently
introduced a main circuit board change. Users
should check 700s for this problem which
shows up particularly badly at 9.5 cm /s when
the input faders are set as if to record at a
high level. If a blank tape is replayed under
such circumstances, and subsequently replayed
without the input programme present, the fault
condition shows up very clearly with splashes
appearing on the blank tape.
Some early samples of the recorder also
exhibited a slight bubbly noise at 38 cm /s,
especially when matt backed standard play
tapes were used. This seemed to be caused by
some second harmonic distortion of the bias
frequency being produced in the record head
circuit, and once again this seems to have been
eradicated on the latest models. Clearly when
a completely new model of tape recorder is
first brought out, many teething problems
arise; frankly the Revox 700 had quite a few.
By now Revox seem to have put almost all of
them right, and therefore the machine can be
very highly recommended. Notwithstanding
this, there is a lot of very complicated logic
which can go wrong, but such logic helps
produce a machine at a price which in many
ways allows it to compete with professional
machines costing at least twice as much. In
general use, the constant forward and backward tension have proved most worthwhile,
since they allow the tape to pass very cleanly
and smoothly over the heads. Master tapes
with many edits play back on the 700 as well
as on any machine I have tried, but on the
other hand I did not find this machine as easy
as some for editing because the moment the
tape was cut the swing arms pull the ends apart.
The spooling is pretty good, although some
shiny- backed tapes tend to ridge. Matt and
semi matt backed tapes however spooled
exceptionally well, even when running between
spools of different sizes. This requires spool
tension to be very accurate.
The subjective wow and flutter was cornpletely inaudible on any programme at the two
higher speeds, and only rarely noticeable at
9.5 cm /s. To check this, I tried recording piano,
using an NAB reel on the left and a 100 mm
reel on the right, and also vice versa; even
under these conditions wow was not audible
at 38 cm /s. I even tried the recorder upside
down with the front of the machine resting on
a table, and the back hand held. Under these
conditions, only a small increase of wow was
noticed. Occasionally on a recording session
an engineer can accidentally touch a spool
during recording, but when I did this the
tension arms took up the slack so rapidly that
the effect was barely noticeable. The stability
of high frequency phase between tracks is
particularly remarkable, especially at the lower
speeds, this proving that the entire tape transport is really well made. My only severe
criticism of the transport concerns the time lag
at the end of spooling or when a tape runs out
on the right -hand reel. Transparent leader
will stop the mechanism quickly in the latter
case, but not quickly enough during spooling,
and often the last 6m or so of the tape gets
thoroughly tangled up under the spool platform. With great care the tape can usually be
extracted without damage, but it is most
annoying. This tiresome reluctance of the
direction sensitive roller to stop should be
improved, since I am sure it causes users much
aggravation.
The machine's capability of automatically
rewinding and recommencing a preset function
will, I suppose, be useful to a few engineers,
but to allow this to happen requires the use of
transparent leader tape in the appropriate
places. Revox can supply this but it is difficult to
obtain elsewhere. The rewind/replay button is
most useful, particularly when the machine is
used for copying. The facility of transferring
automatically from one function to another
has impressed many a client, in addition to
saving a lot of time. I have not found the
pause button so useful, though an action
whereby one depression stops the mechanism
and another restarts it could be an asset.
Although at first I found that threading up
tapes was rather time consuming, I quickly
became used to this, but my colleagues found
the complicated tape path annoying when
editing. Over a period the swing arm adjustments varied slightly, and so occasional
maintenance will be necessary. Unfortunately,
however, on one machine both springs associated with the swing arms broke; as Revox had a
stock of these, the machine was only out of
service for three days. The tape counter is
usefully calibrated in minutes and seconds at
19 cm /s, and it is an easy matter to double or
halve the figure for the other speeds. The
counter is very accurate, and works satisfactorily in both directions. It can, of course, be
reset to zero at any part of the tape. Since the
speed of the recorder is very accurately set by
the capstan motor control circuitry, accurate
tape timing is possible.
Apart from the excellent general operational
features the quality of reproduction obtained
is particularly good under all circumstances.
The constant tape tensioning and provision of
a roller near the record head greatly reduces
scrape flutter and variable modulation noise
effects often produced by longitudinal vibrations of the tape.
Various head blocks can be supplied as
accessories, and we have, in addition to the
normal stereo half track block, a quarter track
version, which works well. The output of the
replay head on this is a few dB lower, and
during replay, pre-set gain controls would have
to be advanced to obtain a calibrated output
level.
The replay response, however, was
virtually identical. We also have a full track
60
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59
REVOX A700
block, and in this case the replay output was
some 5 dB higher than normal, but again the
replay response was flat. We found that it
was necessary to alter the bias considerably
for the half and full track head blocks, and for
the latter Revox cannot supply an erase head
at the moment. FWO Bauch Ltd can however
supply a B62 Studer erase head which will
probably be compatible, although some drilling
of the head block will be necessary for
mounting.
In general use the machine has been most
reliable, although we disliked the attached
mains lead which could not be adequately
stored in the back of the cabinet if fitted with
a heavy duty 13A mains plug. In early machines
the mains lead passes over some of the circuit
boards, and we found that these could be
disturbed, causing certain functions to become
inoperative, in particular one or both recording
channels. Revox have now redesigned the
internal routing of the mains lead, but surely it
would be better to have a more usual type of
IEC mains socket. The machine can be taken
apart very easily as all the different sections of
the electronics have interconnecting plugs and
sockets or edge connectors, thus making it
simple to withdraw and replace any faulty
components.
NEWS
The slide faders used do not seem to introduce any crackles, but on the other hand one
of our replay faders had an intermittent
contact between the bottom and chassis,
making it impossible to take one of the tracks
down to zero output. Some cases of instability
have developed, causing inaudible oscillation
to be produced which can blow the headphone
One
amplifiers and /or external equipment.
machine produces this oscillation when all the
record faders are brought down to the bottom,
and it seems probable that the condition is
connected with earth routing internally. Such
oscillation is usually indicated by one or both
vu meters going on to the end stop, and the
overload light glowing. On high output tapes
the overload light tends to go on rather too
early, and it is a pity that it could not be
replaced by a pushbutton desensitising the
meter by 8 dB or so, as well as changing the
indication to a peak programme type. This
would not require the addition of too much
electronics, but would greatly improve the
ease with which peak levels could be recorded.
Although Revox importers are very unwilling
to modify the 700 specification for professional
requirements, many of the necessary modifications could be simply incorporated. Since the
machine has virtual earth mixing, additional
XLR input and output sockets with balancing
transformers could be built -in to operate
directly into a virtual earth point, and out of
the headphone amplifier's main output. In
such a modification it would be convenient to
reduce all the recording faders to zero and set
up the XLR balanced input with extra pre-sets
to allow a predetermined flux level to be recorded
for the required input level. The replay fader
controls could also be bypassed with a switch
allowing a standard level for the same given
flux. Since the replay equalisation is switched
electronically to different circuitry for all the
three speeds, it would be comparatively simple
to provide circuitry to play back DIN or NAB
tapes. After glancing at the circuit, however, it
would seem difficult to arrange this for recording.
1
also feel that post office type 301
balanced jack sockets would be of more use
professionally than the stereo headphone type
Much room is provided
jacks provided.
internally within the machine for additional
electrodes. It would appear that the manufacturers have allowed this space for alternative
versions that have yet to be produced, although
we understand that the professional A67,
available towards the end of 1975, will not
have identical electronics. The replay head
pre- amplifier of the 700 series uses a stereo ic;
performance can vary from one chip to
another. One machine had very bad replay
noise on one channel, but changing the ic
improved the noise by 10 dB. The replay noise
even at 9.5 cm /s should be well below tape
98
Lyrec multitrack
recorder TR53 -24
be very important because this will
be their first installation in the
Paris area which, they claim, is a
very demanding and exacting
market. On the home front, the
same company reports a confirmed
order to supply a 28/24 - 24
monitor quadraphonic desk, similar
to the one ordered by Vogue, to
Scorpio Sound Studios, London.
Ben Bauer of the CBS Technology Center reports the adoption of
SQ quadraphonic broadcasting by
five major New York fm stations.
The five, WQIV-FM, WRVR -FM,
WHLI - FM, WNYC - FM and
WQXR -FM, are now equipped for
24 -hour continuous SQ broadcasting with the implication that New
York is now an SQ fm town.
New cartridge
THE
Sorry
you found that 'Ambisonics
Part Two' by Michael Gerzon
(August issue) didn't make a lot of
sense, we can explain. Three lines
that should have been on the first
column of p28 were pasted on to
the first column of p30, therefore
making nonsense for the follow -ons
from p26 and p28. Sorry about
this mistake -we hope it didn't
confuse too many readers.
STUDIO SOUND, OCTOBER
CLAIM
that
importance of coherent phasing
results from the audibly unpleasant
effect of cancellations that occur
when stereo signals are paralleled
for mono transmission.
Audio Devices, a division of
Capitol Industries, state that the
improved characteristics are obtained by using a one -piece housing
manufacture; the guides are fixed
and immobile moulded as an
integral part of the cartridge
housing. They also claim that the
new cartridge requires no in- station
adjustments; they arrive ready for
use without needing screw turning
or test tone erasure before use.
A -2SP is available in 12 different
lengths from 20 seconds to 12
Audio Devices Interminutes.
national Inc, 1750 North Vine
Street, Hollywood, Ca 90028, USA.
IN CASE
60
MANUFACTURERS
the phasing characteristics of the
A -2SP cartridge are better than
90 degrees up to 12.5 kHz. The
Audio
Phone: (213) 462 6252.
Devices Ltd, EMI Elstree Studio,
Borehamwood, Herts WD6 1JG.
Phone: 01 -953 1600.
1975
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audio control consoles show the care and attention to detail that are
the mark of the skilled American craftsman. The internal wiring, module construction
console housing and the control display reflect the precision and distinctive craftsmanship
that is characteristic of SPECTRA SONICS.
QUALITY:
SPECTRA SONICS
CAPABILITY:
SPECTRA SONICS
audio control consoles provide an immediate initial capability that may
be increased to 24 inputs and 24 outputs, at minimum cost. The flexibility of the system
will provide line /microphone selection, attenuation, equalization and, through assignment controls, various other combinations for the most sophisticated signal processing
now required in today's studio.
audio control consoles have an established reputation of superior reliability. Through creative design, the circuitry is developed to function well below operating limits to enhance an extended life for the components. Through empirical data
on SPECTRA SONICS audio amplifiers, a reliability rate of 99.9% has been derived.
These amplifiers are used in SPECTRA SONICS audio control consoles and materially
contribute to system reliability.
RELIABILITY:
SPECTRA SONICS
PERFORMANCE:
SPECTRA SONICS
audio control consoles are guaranteed to outperform any other con-
sole in the world in noise, frequency response, distortion, and peak overload. All consoles are provided with documented data acquired in tests of the complete system.
Guaranteed performance specifications are: Frequency Response, - '/ad8 20Hz- 20kHz;
4dBM, output for
Signal /Noise Ratio (microphone input), not less than 82.5dB below
a
50 input (50 ohms source); Signal /Noise Ratio (line input), not less than 87dB below
18dBM
4dBM output for a -` 4dBM input; Harmonic Distortion, less than .01% at
kHz); Intermodulation Distortion, less than .02% at
4dBM; Crosstalk, not less than
60dB at 20kHz (typically 80dB).
(1
Call or write for details on SPECTRA SONICS Model 1024-24:
770 Wall Avenue
Ogden, Utah 84404
18011 392 -7531
6430 Sunset Blvd., Suite 1117
Hollywood, California 90028
(2131 461 -4321
PECTIN
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This listing and description is
taken from information and material
supplied by the manufacturers,
mostly in response to a specific
request. We have
made no attempt to match sterling
and dollar prices, but simply
reproduce what was supplied for a
particular area. In most cases,
asking price fluctuates with the
exchange rate. Correspondence is
not direct, since adjustments occur
for local handling and service needs.
Owing to late information
received in several instances, we
will
be
publishing an
extensive addendum next month.
ALICE
& Stancoil Ltd, 38 Alexandra Rd, Windsor, UK.
Phone: Windsor
AM Range
Fully modular system for quality multitrack recording. Options suitable stereo broadcasting. AM 828 is
a three mono /five stereo continuity console, of
which 14 are in use in UK local commercial radio.
Innovations claimed are special module with in built
limiter and illuminated in /out switch for self drive
operation in broadcasting; comprehensive interlocked tb system available for radio station technical
communications. Prices: AM 16185 £8250, AM 828
£3700. Delivery time eight to 18 weeks.
SM
audio mixers
2
Range
Non -modular professional budget price mixer. For
small studio and mobile applications, available in
formats of 6- 20/1 -4. All normal studio functions
provided. Approx price SM 26/2 basic mixer £720,
SM 2 16/4 typical studio functions £1800. Delivery
eight to 12 weeks.
AD
Survey:
51056/7.
62
Series 3
Inexpensive, new, 'semi -pro' mixer with competitive
noise, distortion and overload performance. 6/2 format with hi/lo switched input, eq and es. Limiters
on both output groups. Phone jack connections at
rear of chassis, where electronics and ps are
mounted on single pcb. Price £294 excluding vat,
delivery ex stock.
ALTEC
Altec Corpn, 1515 South Manchester Ave,
Anaheim, California 92803, USA.
Phone: (714) 774 2900.
UK: Theatre Projects (Sound), 10 Long Acre,
London WCE29LN.
Phone: 01-240 0955/01 -540 2411.
Europe: Altec Sound Products Ltd, 17 Park
Place, Stevenage, Herts SG1 1DU, UK.
Phone: 0438.3241. Telex : 825495.
1220A
Portable mixer/preamp with self- contained reverb.
Ten lo Z, balanced inputs, plus one aux hi level
channel for other devices. Each channel includes:
level, bass, treble, es. Output may be monitored via
two selectable channels. Each channel with independent vu prior to group mix buss; group vus also.
Line and power polarity indicator for shock prevention, electronic crossover for biamp working and
peak limiter circuit. Modular construction. 91 x 61 x
28 cm. 28 Kg weight.
each module can be used as input or output, facilitating multitrack working. Led indication of module
group status. Thus, a 20 module unit (between 19/1
and 16/4, for example) is less than £3000; P &G 1820
faders standard.
AU DIX
Audix Ltd, Stansted, Essex CM24 8HS, UK.
Phone: 0279-813132.
Canada: Double Diamond Electronics Ltd,
Consumers Rd, Suite 105, Willowdale, Ontario.
200
8100
Series of consoles, associated switching and programme distribution systems designed for radio and
tv. Fully modular, desks purpose built to provide
wide range of custom assemblies from standard
production items. Complete world wide installation
and commissioning service.
Studio consoles from standard 8101 10/2 to the 24/2
8102, with four additional subgroups. Vu /ppm
metering for mono or stereo standard; multi metering if required. 8103 portable 12/2 uses same
range of modules. Range of broadcast continuity
systems and self operated radio studio consoles
priced between £1500 and £6000, $3300 and $13 200.
Backed by complete range of rack mounting
equipment (distribution amps, switching matrices
etc) for radio station custom packages.
Standard modules include mic/line input channels
with comprehensive eq, routing, compressor/
limiter, voice-over, stereo width, distribution, line
amp, osc.
MXT/800
For studio and ob use, with up to 21 channels and
2/4 groups. Rack or table top mounting. Simpler
facilities and format than 8100 Series.
M
XT-200
For installations requiring less stringent performance specifications, with compact arrangement,
simple controls and low cost. Suitable ob.
AUTOMATED PROCESSES
Automated Processes Inc, 789 Park Ave,
Huntington, New York 11743, USA.
Phone: (516) 427 -6024. Telex: 960-247.
UK: 3M UK Ltd, Wiley Works, Witley Gardens,
Southall, Mddx.
Phone: 01 -574 5929.
France:
3M France, 135 Bd
19e, Paris.
Phone: 331 202 8080.
Serurier,
Canada: Audio Acoustic Labs,
2
75 940
Cedex
Thorne Cliffe
Park Drive, Unit22, Toronto, Ontario.
AUDIO DEVELOPMENTS
Audio Developments, Hall Lane, Walsall Wood,
Brownhills, Staffs, UK.
Phone: 05433 -5351.
Canada: Double Diamond Electronics Ltd, 200
Forthcoming Surveys
Although we automatically send out a comprehensive circular requesting information, it
cannot reach everyone. Therefore, manufacturers of the following products should let us
know as soon as possible, and in any case not
later than the date given in brackets.
November: delay and reverberation units
(gone to press).
December: monitor loudspeakers (October 2).
January: tape machine controllers-eg synchronisers, auto -locates, remotes (November 3).
February: compressors and limiters (November 28).
We need full address, phone, telex etc of manufacturer and all agents worldwide, in addition to
product details.
62
STUDIO SOUND, OCTOBER 1975
Consumers Rd, Suite 105, Willowdale, Ontario.
France: Studio Center, 3 Rue du Telegraphe, 75020
Paris.
Holland : Sound Techniques, Postbus 206, Alkmaar.
Norway: Siv Ing Benum, Boks 2493, Soli i, Oslo 2.
Sweden: Jan Setterburg, Brevkortsgatan 11, 431
Motndal.
AD 007
8/4 portable unit with comprehensive eq, metering,
osc, two switched ppms, and compressors. Standard
with short travel Ruwido faders, P &G 1520 or 1820 to
special order. Twelve channel extender unit available, connected via designated socket.
AD
031
8/2 'Micro Mixer'; two groups submixed to give third
output; single ppm monitors all functions. Headphone monitor outlet. If compressors required,
fitting is in place of one mic channel. Faders and
extensions available as AD 007, in corresponding
versions.
Super Mini
Retains most of features of AD 007 and AD 031, but
Phone: (416) 425 -7655.
Chromacord Corp, 2343 43rd Ave Lachine, Quebec
H8T 2K1.
3M Deutschland GmbH, Carl- Schurz -Str
D -4040 Neuss 1.
Germany:
1,
Phone: 49 2101
141
Switzerland: 3M (East) AG,
8, 6301
Phone:
PO Box Baarerstrasse
Zug.
411 355 050.
Modular systems for any requirement, based on
sections including the following: 312 preamp,
balanced in for 150/600 ohm, 15 -65 dB gain, reverse
polarity and overload protected; 544 input assign
module; 840 slate /tone; 544 echo send /return; 846fb;
325 line booster; 330 eq preamp; 440 fader, plastic
track, illuminated scale, multigang within 0.5 dB;
475 fader with precision metal wiper; 480 joystick
quadpot; 525 complimiter with threshold, output,
two range frequency dependent release and stereo
link; 550 equaliser, hf 5, 7, 10, 12.5, 15 kHz, mf 0.4,
0.8, 1.5, 3, 5 kHz, If 50, 100, 200, 300, 400 Hz, audio band
pass filter switchable, eq in /out; 553 equaliser, hf,
mf, If fixed frequency; 559 nine band graphic equaliser, approx octaves 35 to 16k Hz; 575 sine wave osc,
20 to 20k Hz in 13 steps, low distortion and output
meter; 701 10W power amp for small speaker or can
systems; 705 50W power amp; 730 2 x 200W power
64
Top to bottom, left: Soundcraft
1214, Allen
á!Heath 16/8, Alice AM 8218
Sphere 'Eclipse' studio console 20 inputs! 16 outputs. Above: Opamp
model 210, Avab ME802S. Below (left): Helios parametric equaliser
module. Below (top): Auditronics Grandson Id model 110 -8 (bottom):
Interface series 300, 16 channel.
41/11VINVü011I111111 )
Nli flttll
63
SURVEY
Jolla, California 92037.
Phone: (714) 452-0813.
Spain : Singleton Prods, Via Augusta 59, Desp 805,
Edifico Mercurio, Barcelona 6.
Phone: 228 3800. Telex: 54015.
Italy: Ing Oscar Roje, 20147 Milano, Via Sant'Antalone 15.
Phone: 415 4141. Telex: 39202.
Finland : Into Oy, PO Box 153, Helsinki 10.
Phone: 90- 11123. Telex: 12 -1836.
South Africa: Tru -Fi Electronics SA, (Pty) Ltd, PO
Box 31801, Braamfontein Tvl.
Phone: 838 4930.
Japan : Kawamura Electrical Laboratory, No 34
Yarai -Cho, Shinjuku, Ku, Tokyo 162.
Phone: (03) 250 -0401. Telex: J 22748.
minated vu; four es. Tv version available similar
1204 standard with nine frequency eq, direct feed
switching bypassing main buss; four mixing busses
Sub 1, Sub 2, Aud and Pgm, usable for separate
simultaneous mixes. Eight monitor mute switches.
1604
Portable
Supplied standard as up to 16/4 console using
various standard modules. Includes standard es,
fb, monitor and metering options. Typical price 16
input $17 790.
Normally fitted 10 or 12 channels but available up to
21. Two or four group outputs. Version with full
quad panning on all channels. Two es, two fb, pfl,
osc, tb, standard monitoring. Both mic and line
bridging inputs to channel separately gain adjustable. Five -band eq: hf shelving curves, three mid
bell, and one If shelving. Each band has frequency
select /cut and booster control. Table top or stand
versions. XLR fitted.
E Range
Multitrack recording console available in formats up
to 35/32. Eight sub -mixing groups; 2/4 es, 2/4 fb;
quad monitor with matrix encode /decode insertion
point. Monitor up to 32 with sync /playback/record
switching linked with Cadac Dolby module and
multitrack
tape
switching. Tuchel multiway
connectors.
module.
A M4A
Small, modular desk, arranged as block housing and
La
amp; 940 automated fader, with plastic track and
led ± cursor indication, write /safe/update switching; 954 programmable parametric equaliser hf 800,
1.8k, 3.5k, 7k, 16k Hz, mf 200, 500, 1k, 2k, 5 kHz, If 30,
60, 130, 260, 600 Hz, bell and notch options, with
write and in switching, compatible Allison /Auto-
mated programmer.
Automix
For typical channel arrangement on Automix fully
automated console mixdown system, see September
Studio Sound p56. Console available in 24 or 32
channel options as standard, in conjunction with
Allison /Automated programmer. All functions
automated, including eq, subgroups and pan. Multiple led indications of status and related functions.
2488
Supplied standard as up to 24/16/24 console with
extra capacity for particular requirements as necessary. Typical price 24in with 24 monitor channels
$33000; 12 in with four monitor channels $22 930.
AVAB
Avab Elektronik AB, Kungsgatan 5, 411
Goteborg, Sweden.
Phone: 031 -11 20 32/ 031 -11 20 34.
UK: MCI (Professional Studio Equipment) Ltd,
19
21
Claremont Square, London N1 91X.
Phone: 01 -278 2288.
USA: Audiotechniques, 142 Hamilton Ave, Stamford, Connecticut 06902.
Phone: (203) 359-2312.
Audio Industries Corpn, 1419 Nth La Brea Ave,
Hollywood, California 90028.
Phone: (213) 851 -4111.
Canada: Chromacord Corpn, 2343 43rd Ave
Lachine, Quebec H8T 2KI.
ME 802 S
Portable 8/2 mixer fitted in standard Antler briefcase. Channels include bass /treble control, pan,
balanced mic gain, es gain, tape and echo return,
subgroup pre /post. Two 10 band octave graphic
equalisers patchable. Two subgroups arranged on
short sliders. Peak reading led display. XLR in /out
connectors.
Custom Multitrack
Two modules per channel: eq more complex than E
or Portable ranges: and channel routing module. Full
group reinsert and quad pan on each channel
regrouping and echo return. Comprehensive monitoring. Full custom design service available.
Standard 20 channel broadcast console under
development. Custom facilities available.
Automated mixdown (Allison) available with any
console; may be fitted to existing desks.
Water Lane, Oakington, Cambridge CB4 5AL,
UK.
Phone : 022023 -3737.
High quality desks for theatre use. Cue lights, show
relay/communications facilities, Is switching, tape
remote all on front panel.
Standard model provides: 10 input channels, mic/
line sensitivity, treble, continuously variable presence frequency /gain between 270 Hz and 6 kHz, hi
pass filter 170 Hz at 6 dB /octave; two aux send pre/
post; pan; pfl; linear motion fader. Also, four direct
inputs each with pan, rotary gain and pfl; two main,
two aux groups with pfl; main groups with set level
control. Any input or group may be metered via
pfl, also stereo and off -tape output monitoring.
Communications feed. Switching eight Is lines. Jack
bay; connectors locking DIN. High contrast marking, colour codings. Separate ps; semi -modular
construction. 63 x 63 x 28 cm, weight approx 20 Kg,
price standard £1300; many options available in
format and mechanics.
CADAC
Cadac (London) Ltd, 141 Lower Luton Rd,
Harpenden, Herts AL5 5EL, UK.
Phone: 05827- 64351. Telex: 826323, Cadac
Harpden. Cables: Cadac Harpenden England.
USA: Cara Pacific Sales Co, 3050-F Via Alicante Dr,
64
STUDIO SOUND, OCTOBER
1975
fitting plug -in modules. Standard Cetec modules are
accommodated, giving wide flexibility according to
specific operational requirement.
Further series of compact cabinet mixers is available
varying from simple 8/2 downwards, in combinations
of impedance, input type and connector.
CROSSROADS
Crossroads Audio Inc, PO Box
Texas 75219, USA.
Phone: (214) 526 -1636.
19371,
Dallas,
Minipro
Concert sound reinforcement mixer. 16 in, three out;
balanced input; simple eq; prefade monitor mix
buss; post fade echo /effects subgroup, master eq
on main and monitor outputs; XLR connectors; two
large vu meters.
Pcb construction; all controls rotary. Weight 14 Kg
approx, length less than 77 cm. Price $1750.
CRYSLON
Cryslon Electronics Ltd, Unit 4 Berrington Rd,
Sydenham Industrial Estate, Leamington Spa,
Warwickshire CV31 1PN, UK.
Phone 0789- 66282.
:
CETEC
Cetec Audio USA, 13035 Saticoy St, North
Hollywood, California 91605, USA.
Phone: (213) 875 -1900. Telex : 910 499 2669.
: Cetec UK, Sapphire House,
London W5 2BP.
Phone: 01 -579 9145. Telex: 935847.
4
Large scale, flexible console based on the following
modules, up to 40/24 configuration: input module 24
illumi.ated push button assign; mic preamp pad/
gain; graphic or three way eq; mute, solo; extensive
pan in quad and stereo groups; es send automation
control, and vca. Submaster attenuation; full and
extensive multitrack monitor switching. Further
system options include simultaneous quad /stereo/
mono mix busses; automated joystick panners;
automation encoder, decoder and interface wiring;
rough mix monitor and cue sends derived from input
Broadcast
UK
CAMBRIDGE ELECTRONIC
WORKSHOP
Series Ill
Series
16
Uxbridge Rd,
10
10/2 portable console with ten stereo input channels
and ten switchable remote stereo inputs; comprehensive tb and cueing systems; stereo headphone
output, remote tape controls; clock; two ps modules
(remote) each of which handles requirements.
Available in mono /stereo /quad forms with eq if
desired.
Series
2000
Available in formats of up to 32/24, based on the
following modules: 712L nine frequency graphic
eq /mic amp; 711L eight frequency eq /mic amp; 311L
mic amp; SM -5 five channel switch push button;
SML switch module lever, 24 channel.
Series
DUKANE
DuKane Corp, 2900 DuKane Dr, St Charles,
60174, USA.
Phone: (312) 584 -2300.
Illinois
20
Live music console. Up to 30 inputs, four program
outputs, mono output, stereo output, two fb, one es.
Mic /line and optional switching for up to 48 additional remote inputs. Phase; solo; attenuate to
60 dB; group solo, echo return; programmable mute
for four independent presets; three way eq on all
inputs; led channel -on; illuminated vu for all outputs, ppm available; plug -in modular construction.
Series
Complete manufacture, design, installation and
after -sales service offered for theatres, film studios,
local broadcast stations. Consoles manufactured
range from small compact portables to multi -channel
and multi -group studio facili.ies, as required. Stage
manager systems, tb, cue, show relay and security
systems. All ancillary items may be supplied. All
console and rack systems built from standard range
modules: mic amp, various eq, mixer, line amp, tone
osc, power amp etc presented on standard front
panel 177.8 x 50.8 mm; all plug -in fitting.
1204
For high quality recording, broadcasting, sound
reinforcement and film work. 12 mic /line inputs,
wired 16; complete eight frequency eq with es and
cue on each channel; four output groups with illu-
13B465
Up to 16 input channels, to three output groups;
overload indicator on channel and group; cue
channel to monitor any combination in /out. Supplied
with two large vu meters. Designed for mass
audience facilities.
2A75B
Mixer-amplifier for pa and sound reinforcement
purposes. Five inputs, each taking mic /line /disc,
three pad positions; balanced output. 2A768 is
associated mic input expander, with five additional
channels.
EAGLE
Eagle International, Precision Centre, Heather
Park Dr, Wembley HAO 1SU. UK.
Phone: 01 -903 0144.
Eaglint Wembley.
Telex:
922131.
Cables:
66
AUTOMIX
A Completely Programmable Mixdown Console
Automix as a manual mixdown console is
incomparable. As a programmable console,
it permits new standards of perfection and
artistry.
You may capture every detail and nuance
a mix from up to 32 inputs and 4 echo
channels. When programmed, your mix may
be precisely repeated as often as desired, or
each element of sound on any track may be
of
improved individually or in combination.
The audio paths are entirely separated
from the DC control circuits. Voltage control amplifiers and state variable devices in
the audio paths provide for all functions:
level, localization, reverberation, and equalization. Control of multiple audio paths by a
single manipulator (grouping) is possible for
all functions. An optional video screen displays the quad sound field, identifying each
input, as a numeral, in its respective aural
position.
Extraordinary performance is achieved at
a very ordinary price. Automix,even with a
companion Automated Processes' studio
mixing console,can be obtained at substantially lower cost than a conventional console
of comparable numerical capabilities.
AUTOMATED PROCESSES INC.
785 PARK AVENUE, HUNTíNGTON, NEW YORK 11743.516- 4274024
65
IN
SURVEY
Range of small mixers. Self powered with two PP3
batteries.
FF 1
Four channel mono mixer and preamp.
Hi /lo
switched mic inputs, channel and master sliders.
Switchable aux input on one channel. £28 plus vat.
FF 10
Designed for disco use: two stereo disc, one stereo
tape and one mono mic input. Channel and master
sliders. £34 plus vat.
FF 32
Seven channel stereo programme mixer and pre amp. As FF 10 but with additional pfl. HA 10 headphone amp may be used in conjunction. £36 plus vat.
MP 12
Six channel stereo /mono mixer and preamp. Mic
inputs switchable hi/lo impedance. £34 plus vat.
FAIRCHILD
Fairchild Sound Equipment Corpn, 75 Austin
Bvd, Commack, Long Island, New York 11725,
USA.
Phone: (516) 543-5200.
UK: Jacques
vices,
Levy Professional Recording SerCarlisle Mansions, Carlisle Place, London
6
SW1
Phone:
01
-834 9248.
FPC
Portable, flat console available in formats between
8/2 and 16/8. Balanced mic input with gain, If, hf
boost/cut, peak selectable. Vu metering on groups,
balanced out; 25 hours operation on one set 'C'
batteries; solid aluminium construction. 72 x 62 x
5 cm, weight 12 to 19 Kg depending on format.
ICBM
Series of modular broadcast consoles and ic broadcast modules (ICBM) including mic input module,
line and hi level input modules, remote input, output, monitor and communications modules. Metering
via vu in console shell; wide format flexibility.
FIC
Flexible modular system for recording. Input module
includes level, select and pad switches, input fader,
es and gain pre /post, compressor, hi and lo eq, fb,
vu. Output module includes slider, echo return,
compressor, eq, vu meter. Monitor module includes
10 x 10 select matrix, slate, tb.
GATES
Gates Divn, Harris -Intertype Corp, 123 Hampshire St, Quincy, Illinois 62301, USA.
Phone: (217) 222.8200.
UK: Lee Engineering Ltd, Ashley Hcuse, Ashley Rd,
Walton -on-Thames, Surrey KT12 1JE.
Phone: Walton -on- Thames 28783/4. Telex: 928475.
Cables: Leetech.
Dualux and Gateway 80 cabinets are simple mix and
cue units for broadcast and related work. Single or
dual channel vu metering. Monaural side cabinets
available as extension slaves, in similar styling and
layout.
HEATHKIT
Heath Co, Benton Harbour, Michigan 49022,
USA.
Phone:
(616) 983-3961. Telex: 729421.
UK. Heath (Gloucester) Ltd, Gloucester GL2 6EE,
UK:
Phone: 0452- 29451. Telex: 43216.
Mixer kits to be released October 1st 1975.
T M -1626
Simple 6/2 mixer. Four mic input channels hi /lo Z,
one with pan. Two aux inputs; all inputs switchable
left /right. Two illuminated vus, with adjustable led
peak indicators. Rear panel jack access to mixing
buss. Slider controls. £85 inc 25 °; vat.
TA -1620
66
STUDIO SOUND, OCTOBER 1975
Pa control amplifier and amp. Six balanced low Z
inputs, each channel having level, bass and treble,
reverb on /off. Mic pads 18 dB. Two channels high
level, aux input optional. Reverb built in. Anti feedback switches on band gain. 100W power amp.
Lighted output meter, switchable sensitivity. Pcb
construction. Price £248 including 8% vat.
HELIOS
Helios Electronics Ltd, Browells Lane, Feltham,
Mddx TW13 TER, UK.
Phone ; 01-890 0087/8/9.
USA : To be appointed shortly.
Canada: Noresco Manufacturing Co Ltd, Professional Products Divn, 100 Floral Parkway, Toronto,
Ontario M6L 2C5.
Phone: (416) 249 -7316. Telex: 06- 217876.
Norway: Slv Ing Benum & Co, Boks 2493, Solli,
Oslo 2.
Phone: (02) 56 57 53.
Germany :Elmus GmbH, D1 Berlinl2, Herderstrasse
16.
Phone: Berlin 312 20 12.
Italy: Audio Consultants srl,
41100 Modena, Via
Emilia Est 181.
Phone: (059) 36 79 59.
Portugal : Tecta Lda, Rua Eca de Queiros 20 3° D,
Lisboa.
Phone: 56 04 05.
South Africa: General Optics Co Ltd, Film and
Electronics Divn, PO Box2409, Johannesburg 2000.
Phone: 836 4275/9851. Telex: 43 -0057.
Service offered is custom design based on a wide
range of modules and accessories. Areas covered
are studio, multitrack mobile, broadcasting, film
dubbing and high quality pa.
Alternatively, a 'semi- standard' approach uses
modules for 8/16/24 track recording (PS Series) and
10 to 24 channel broadcast in SB Series. Recent
introductions includes range of input modules, incorporating separate line -in control on slider, with
parametric eq in three or four sections. Continuously
variable frequency and Q, they can also be switched
between bell and shelf curves; equalisers may be
sold separately. Provision is made for automation
using proprietary equipment.
Other services are: consultancy in design and
equipping recording studios; provision of complete
recording studio packages across design, architect
and builders instruction, equipment supply, installation and commissioning; specialist design and
building of mobile recording units and vehicles.
HH
HH Electronic, Industrial Site, Cambridge Rd,
Milton, Cambridge CB4 4AZ, UK.
Phone : 0223 -65945/6/7.
USA : Audiotechniques Inc,
142
Hamilton Ave,
Stamford, Connecticut 06902.
Phone: (203) 359 -2312.
Canada: Paco Electronics, 45 Stinson St, Montreal.
Phone: (514) 748 -6787.
France: Techniques et Conpemporaines, 6 Rue
Monsigny, Paris.
Phone: 266 36 89.
Belgium: Delba Equipment SA, 28 Rue Bu, Pabellion, Brussels 5.
Phone: 376 6034.
Holland : A. Hardes BV, Oude Gracht, Utrecht,
Holland.
Phone: 31 61 44.
ICE
ICElectrics Ltd, 15 Albert Rd, Aldershot, Hants,
UK.
Phone 0252 -28514.
:
Ice mono
for aux, mic 1/2 and disc 1/2/3.
Overload capability 20 dB all inputs, output 760 mV.
Bass /treble controls, headphone monitor. Tape
socket. 13 x 50 x 11 cm. Price £123.66 inc 8% vat.
6/1 mixer, preset
Ice stereo
As mono machine but with aux and disc inputs
ganged stereo faders. Tape output may be used as
echo send/return. 13 x 50 x 11 cm. Price £141.75 inc
8%
vat.
INTERFACE
Interface
Electronics,
3810
Westheimer,
Houston, Texas 77027, USA.
Phone: (713) 626 -1190.
Europe (Common Market): Audio Products International Viale Rimembranze di Lambrate
20134, Italy.
13,
Milan
Combinations of mixer configurations for stereo,
four and eight track working.
Series
100
Four group output mixers, accommodating up to
24 input channels. Four interchangeable modules
provide for wide functional range as follows: í00D:
track route; pan; es (post); hi and lo frequency eq;
solo; gain set; input pad; line /mic choice; slider.
1008: as 100D but with three band eq at frequencies
50/100/250 Hz, 500/1.2/2.4k Hz and 4/8/12k Hz 100C:
compressor input module to 40 dB, trackswitch, es,
hi /lo eq solo /gain /line -mic and slider. 100AQ and
100CQ: various panning options, with typical channel functions. 1000: high level, four input module for
level, cue, pan for feeding four outputs with four
track signal. 100R: combination sound -system
and stage monitor module with basic monitor switching and channel -type controls of eq etc. 100J:
elaborate version of 100R, principally with three -band
eq. Output panels include vus for each of four channels, and submix options from main groups. Built -in
Hammond spring reverb available on one channel
only as option, as is phantom powering. 100L: gain
pots four each of four sub and main groups. 100K:
cue system controls, for each of four send busses,
with associated controls, including monitor insert.
Price range $2100 to $5040.
Series
200
Small, compact stereo portable mixer. Eight XLR
inputs, vu on two output groups, echo send /return,
conductive plastic faders, input pad switch. Plug -in
module and ic construction. 25 x 39 x 8 cm. $1500.
Series 300
and 24 input eight group output desks. Modules
100 series except as required by eight group
working. Fully modular. Module 308A is track select
push button, solo, pan, es and fb pre /post, six band
eq at 100, 300, 600 1.2k, 2.5k and 5 kHz. Price range
$7560 to $12 300.
16
similar
Also available: X0312 electronic crossover, three way continuously tuneable.
ITA
Industrial Tape Applications,
5
Pratt St, London
NW1 OAE, UK.
Phone: 01- 485 6162. Telex: 21879.
France: Reditec, 27 ter Rue de Progress,
93107
Montreuil, Paris.
P M12/2
Belgium:
Portable 12/2 mixer for high quality pa or recording
applications. Led output vus and electroluminescent
lighting on controls. Channels include hi /balanced/
lo, line gain, eq ±16 dB at 40 Hz, ±12 dB at 1.8 kHz,
+16 dB atl5kHz; fb and es; pan; monitor switchable
pre /off /post fade; mute; sliders on channel, groups
and subgroups. Additional echo return. Monitor
output may drive cans, switchable between channels, groups and subgroups.
Wijgmeal.
TATA,
Kerkstraat
16,
3020
Herent
10.4
Portable or studio desk for recording or pa. Modular
construction in fixed format for high turnover /low
cost. Facilities include: balanced mic /line input with
gain; lo, mid, hi eq; es, fb; pan between groups 1/2
and 3/4; channel assign; fader; four limiters with led
72
0.
Studio Sounds
MXR
OISTONTION
MXR
Innovations
Setting the Standard of the Industry
Ose
0rriS 32-34 Gordon
ouse -boo London
,
\W5 I\E.
fáCF-16JFSt
571111O MIX
Top left: Shure model M688 -E stereo microphone
mixer. Far left l-r : Raindirk broadcast range channel
unit, Schlumberger eq module, Schlumberger main
frame. Above: Studer input module.
SURVEY
and broadcasting.
between line and balanced mic 200 ohm. Output
600 ohms balanced main groups, monitor 5k ohms
LMX3
indication (variable); four monitor volume controls
fed to stereo monitor output. Headphone socket;
four echo returns. Connections via phone jacks.
Weight approx 11 Kg. Price £647 plus vat.
20 input version £990, eight group version £1260.
LAMB
Lamb Laboratories, Lamb House, Church St,
London W42PB, UK.
Phone: 01-9954551.
USA: Lamb Laboratories,
155
Michael Dr, Syosset,
8/2 mixer using rotary faders. Echo send and reinsert.
Input switchable mic /line. Size 13 x 50 x 18 cm.
Weight approx 4 Kg. Price $750; mono version $575.
LMX4
Five input mixer with subgroup routing and return.
Single vu meter. Each channel with mic orline option.
With one mic amp $875.
LMX5
Similar LMX4 but incorporating 10 slave charnels
only. Output to be fed through transformer coupling
to mic input elsewhere. Power internal or external.
With one mic amp $875.
New York 11791.
Phone: (516) 364-1900.
3637 Cahuenga Bvd, Hollywood,
Phone: (213) 867 -1200.
California
90068.
Also available: compatible eq and reverb units aid
extended versions of above.
MALATCHI
Malatchi Electronic Systems Inc, 3731
Ave, Denver, Colorado 83206, USA.
Phone: (303) 321 -3520.
E
Colfax
Delivery of all units from immediate stock. (424 and
426 due for release shortly.) £195 plus vat.
Range of audio mixi..g systems and related equipment for live sound reinforcement and for recording,
along with lighting mixing and control units. Mixers
use 'top grade commercial and military grade components'. Available are quad, stereo and mono
configurations with any number of input channels
as required. Format totally modular. Installations
include Shady Grove Theatre, Washington DC and
Warehouse Restaurant in Denver.
LANG
MARTIN
P M L424
Identical with PML422 but configuration rearranged
for dual use as four track mixer.
P M L426
As others, but with six input channels only.
Phone:
14 E
39th St, New York,
Martin, 320 W 46th St, New York, NY 10036, USA.
Phone: (212) 541 -5900.
(212) 725 -8110.
SLM -1020A
Range of mixers and associated units for recording
72
STUDIO SOUND, OCTOBER
NY $2495.
SBC
82
Stereo broadcast console, similar specifications to
SLM- 1020A.
Designed for broadcast /disco, ten
inputs on five dual -ganged sliders into two groups,
with mono cue facility. May be used with 234 mic/
line cards or 234PE phone eq cards. Price without
input cards $1549, with extra cards at $50 each.
MCI
MCI Inc,
PML422
4/2 portable mixer. Unbalanced mic inputs 200 ohm,
line greater than 20k ohm; line out -f -10 dBm unbalanced. Two adjustable vu meters. Input sensitivity control, treble/mid /bass lift /cut; es; pan; stereo
limiters switchable; pcb construction; linear sliders.
Lang Electronics Inc,
NY 10016, USA.
unbalanced. Es 600 ohms unbalanced. Equalisers
per channel at 50/100 or 200 Hz, and 3k /6k or 12k Hz.
Separate channel pan. 27 x 39 x 19 cm overall,
weight approx 11 Kg. Twin vu meters. Price fob
1975
Compact
10/2
console.
Channels
switchable
Florida
Phone:
4037 NE 6th Ave,
33398, USA.
(305) 566 -2853. Telex:
Fort Lauderdale,
51 -4362.
UK MCI (Professional Studio Equipment) Ltd,
Claremont Sq, London N1 91X.
:
Phone:
01
21
-278 2283.
J H- 428/440
Modular system largely using plug -in board construction. Channel module includes 16 channel
assign buttons, with 'direct assign' facility straight
through to associated tape track. Led indication.
Mic amp pad 20 dB, max gain 60 dB, headroom
more than 28 dB. Mute channel; eq to /hi boost /cut
total four frequencies, m:d boost /cut half octaves
150 to 7k Hz. Monitor with individual quad pan,
separate I/r and f/b control. Four es available at
remix. Overall module states mic/tape /remix
designated by selector on status module.
Auxiliary module provides cue select, solo, echo
level, osc, slate output select, separate tb, fb and
74
RAINDIRK LIMITED,
Downham Markel, Norfolk.
TeI.(03663)
216E & 3617
'SERIES 2'
12/4
CALREC
MIXERS.
CALREC AUDIO LIMITED
HANGINGROYD LANE
HEBDEN BRIDGE
YORKSHIRE HX7 7DD
TEL 0422 84 2159
73
SURVEY
MIDAS
slate levels. Master module contains fb and es
master, four echo returns and master level fader.
Full quad panning as appropriate. Control room
monitor module permits quad, stereo and mono
monitoring of nine signal sources. Automatic muting
of unwanted monitor sends as necessary. Solo trim
and master monitor level facilities. Other standard
inclusions: monitor select, meter select, vu /peak
option, solo indicator and level control, monitor
channel input select.
MCI Spectra -Vue utilises existing vu or light
meters to read half octave spectrum distribution for
selected signal. 18 half octave bands 45 to 16.5k Hz.
Agc corrects input levels from -30 to +20 dB to
reference. Optional standard extras: 24 track buss,
phase reverse, tape solo on in /out module, individual
es /fb access for tb etc, monitor trim and mute, quad
studio monitor, alternate speaker switch, equalised
peak reading light meters, 56 extra tie lines, phase
meter, etc.
Prices: eg JH-428 -8 VU, 28/8 standard console
$16 785. JH-440-40 LM with 24 light meters,40 channel
console $48941. Sterling prices approx £8500 and.
£25000 respectively, dependent on exchange rates
J H -528
Preliminary specification similar 428/440 series but
facilitating automated mixdown. 24 channel select,
selection indicator, eq in /out switch, fader /monitor
switch, six separate subgroups, with
and 2 on
sliders; local mute disconnects channel mute from
automated muting system. Led indication associated
with vca auto write /read functions with monitor and
fader override available. Increased flexibility of
'communication strip'. Master strip as before with
rearrangement and mix trim, calibrate override
switch, extended main group and sub group pan
select, solo, mute and override. 'Comp' reduces
quad /stereo separation to 18 dB, filter rolls 12 dB/
octave below 30 Hz.
Control strip facilities include monitor, send,
solo trims, 'alt centre switch' to shift quad 'room
centre' from engineer to producer position. Automated option provides full control of level functions
only, including all subgroups. Data storage on associated slave tape machine. Level matching achieved
by vca slewing between read /write levels, with
variable time constant. Preliminary details received
of compatible 24 track recorder with 76 mm tape:
wider signal paths with increased data storage for
automated mixdown.
1
Mc MARTIN
McMartin Industries Inc, 4500 Sth 76th St,
Omaha, Nebraska 68127, USA.
Phone: (402) 331 -2000.
UK:
Lee Engineering Ltd, Ashley House, Ashley
Rd, Walton -on- Thames, Surrey KT12 1JE.
Phone: Walton -on- Thames 28783/4. Telex: 928475.
Cables: Leetech.
B -800
Midas Amplification,
N155QS, UK.
Phone: 01- 8006341.
Belgium: Louis
87
North Grove, London
de Potesta, Rue Th Decuyper 134,
Brussels.
Phone: 771 30 63.
1200
Two basic ranges, of portable, mixing and studio
systems.
Portable
For quality sound reinforcement and 2/4 track
recording appl ications. Based on following modules:
PR 001 input /output module, mic /line optional, line
gain and input attenuator 30 dB, 600 ohm balanced
mic input; eq +16 dB at 50 and 15k Hz ref 1 kHz,
+14 dB at 3.5 kHz, variable Q; two each fb and es
normally pre and post; carbon track Ruwido fader;
pan; pfl. PR 002 similar, but fitted P &G fader and
extended eq; bass cut, presence at 1.5/3.5/7 kHz;
subgroup route switches optional. PR 003 as PR 002,
designed for recording; extra mute/channel switch/
pan grouping. Output module PR 010 includes post fader break points; PR 011 with line in /out monitor
and amp. Fb and es /return module mixes and reinserts. Tb, pfl, limiter and crossover modules available; jack field optional.
Studio
Comprehensive range of modules, with facilities of
varying complexity. Typical channel includes eq
+18 dB at 60 Hz, +16 dB at 700/1k/1.5k/2.7k/4k/7k Hz,
+16 dB at 10 kHz, alternatively +,16 dB at 40/80/160
Hz, ±16 dB on variable control four ranges 30 -300,
150 -1.5k, 300 -3k, 1.5k -15k Hz, and +16 dB at 7/15 kHz.
Hi pass filter 80/120 Hz, 18 dB /octave; two fb and es,
former with pre /off /post; mute, pfl /afl; full pan,
monitor and tb facilities. P &G 1820 fader standard,
1520 fitted to special order. Vu or ppm metering as
required; led overload optional.
MUSTANG
Mustang Communications, 31 Nelson St, Scarborough, Yorks, UK.
Phone : 0723. 63928.
Abroad : distribution network being set up.
Range of mixers primarily intended for performance
and may find studio application. Mixers available in
rack or free standing format, with cabinets for
racking also available. Delivery 'usually held below
10 days'.
MM Series
Modular options based on MM4 and MM6 four and
six input mixers. Associated modules for mic hi/lo,
mag /ceramic pu, high Z tape, balanced line etc.
Prices (trade) range MM4 £52.96, MM6 £62.61 with
extras around £5 per module. Compatible power
amps offered, and range of lighting control.
MMA Series
As above, but with integrated power amplifier. 50W
and 100W versions, adding approx £30 and £40
respectively to the price.
NEVE
Series
Modular, providing for push button selection of 27
input sources through eight mixing channels. Standard models B -801 mono, B -802 stereo, B-803 dual
mono, B-802 -S1 dual stereo and B- 802 -S2 stereo mono. First three channels lo mic; next four channels high level unbalanced aux sources; remaining
channel hi level balanced. Special configurations as
required. Step attenuators; 8W monitor amp
modules; selective intercom /talkback; two panel vu
meters.
Rupert Neve & Co Ltd, Cambridge House,
Melbourn, Royston, Herts SG8 6AU, UK.
Phone: 0763-60776. Telex: 81381. Cables: Neve
Cambridge.
USA : Rupert Neve Inc, Berkshire Industrial Park,
Bethel, Connec:icut 06801.
Phone: (203) 744-6230. Telex: 969838.
Suite 616, 1800 N Highland Ave, Hollywood, California
90028.
Five channel 'mini -console' in 9 cm high rack unit.
Accommodates up to 13 mic inputs, with hi /lo input
level switching on three channels, monitor and cue
Phone: (213) 465 -4822.
Canada: Rupert Neve of Canada Ltd, 2719 Rena
Road, Malton, Ontario.
Phone: (416) 677 -6611. Telex: 0696 8753.
Germany: Neve Gmbh, 6100 Darmstadr Bismarck strasse 114.
Phone: (06151) 81764.
Elsewhere: other agents in major countries
worldwide.
facilities. All inputs transformer
talkback facility.
A complete range of mixing consoles is offered,
B -500
Similar B -800 Series, with disc input modules available. Basic five channel input to one or two output
channels.
Accu -five
74
isolated; cue/
STUDIO SOUND, OCTOBER
1975
together with full installation for recording studios.
Standard designs, some available from stock,
between 5/1 and 32/16/32 formats. Stock consoles
include Kelso 10/2, Melbourn 12/2, Specification 8014
16/4/8, Specification 8024 24/24, Specification 8034
20/4/16, Specification 8036/46 24/8/16, Specification
8038 24/16/24, Specification 8048 32/16/32.
Standard designs available for film dubbing,
radio and tv, including local radio scale. In all fields,
range is from largest to smallest consoles. Despatch of stock consoles 'rarely longer than 12 weeks';
custom building requires six to eight months
depending on size and complexity. 12 months 'no
quibble' guarantee precedes regular maintenance
service with one to three visits per year, and 'flying
trouble- shooting' staff.
Computer -aided mixing facility shortly to be introduced, based on electromechanical servo system for
optimum distortion performance (Necam).
PEAVEY
Peavey Electronics Corp, 711 A Street, Meridian,
Mississippi 39301, USA.
Phone: (601) 483 -3565
1200
Self- contained, portable mixer for recording and
sound reinforcement work. 12 channels each including: balanced, low Z mic inputs, unbalanced high Z
line inputs switchable, input /line attenuate, high/
low eq on all channels, stereo pan, three sub groups
switchable pre /post, channel slider. Sliders on
master groups, with master eq low /mid /high;
effects master, return with pan; reverb master,
return with pan; balanced output with illuminated
vu metering, adjustable. Price $949.
PHILIPS
Electro- acoustics Division, NV Philips Gloeilampenfabrieken, Eindhoven, Netherlands.
Phone: (040) 732904. Telex : 51121 PHTC NL.
UK:
Pye Business Communications Ltd, Cromwell
Road, Cambridge.
Phone: (0223)) 45191.
USA: Philips Audio Video Systems Corp, 91 McKee
Dr, Mahwah, New Jersey 07430.
Phone: (201) 529 -3800.
SM4
Modular range of units for flexible set up of custom
systems, intended primarily for pa and theatre area
as well as 'semi- broadcast' use; with associated
power amps.
Modules include the following, with more to be
introduced subsequently: LBB 1140 mixing preamp,
various inputs for pick up, music, mic and line, bass/
treble .i 14 dB, vu meter; LBB 114250W mixing amp,
as preamp with amp; LBB 1102 50W power amp;
LBB 1143 100W mixing amp; LBB 1103 100W power
amp; LBB 1104 200W power amp; amp/attenuator
LBB 1151/01; LBB 1151/02 tone control amp, hi /mid/
lo boost and cut; filters LBB 1151/03, as tone control
amp before but with sliding frequency for anti resonance treatment; LBB 1151/05 simple comp limiter; LBB 1151/06 gong /chimes/alarm unit; am
and fm tuner modules; control desks for small desk
installations; sliders, vu module and mains control;
signal push button module; five button, also available with illumination.
LBB 1146/00
Simple stereo mixer with various inputs for mic,
music, tape. Five channels.
LDC 25
Designed for tv, radio and music studio using narrow
30 mm modules. 20 in and four out less than 1m wide,
with space for extra four channels /groups. Channel
modules have mic control, eq, hi /mid /lo, pan and
mix to four busses; tb and fb reinsert on groups;
desk is mainly of pcb construction, with divided ps
system. Standard versions from stock 1976 onwards,
price $20000 to $40000, depending on option.
76
1110.
THERE'S NO BETTER VALVE!
THE PML 422 MISER
AT E195...,
Flexible, portable, 4 in x 2 out,
low cost, semi -pro mixer with EQ at 15kHz,
1KHz, 50Hz on input channels.
Switchable, stereo tracking limiters on outputs.
Elaborate signal routing
Echo send and return.
Plug -in
circuit boards.
The ideal mixer building block.
Full details from
LAMIFRIDLECIEW
Lamb Laboratories Ltd
Lamb House Church Street
London W4 2PB
Telephone: 01 -995 4551.
75
SURVEY
PYE
Pye TVT Ltd, Coldham Lane, Cambridge CB1
3JU, UK.
Phone:
0223- 45115.
Telex:
81103.
S M8
Eight input channels selectable from three input
channels: mono mic /line, stereo disc or stereo hi
level. Channels include sensitivity, pfl, es, fb, pan.
P &G faders standard. Custom version with switching
for up to 48 sources. Talkback may be used externally if required. Eq +8 dB at 3/5/8 kHz and 60/120/240
Hz and ±10 dB at 0.7/2.4/4 kHz. Fader backstop
switches accessible for cue or machine start. Mono
output from normal two groups working. Wide
range monitoring and flexible switching, with interlock of talkback.
SM12
Compact 12/4 portable /studio /ob mixer based on
narrow 30 mm modules. Channels include: mi/line;
pan between predetermined groups; eq ±15 dB at
30/60/120/240 Hz, 0.5/1/1.4/2.4/4 /7 kHz and 2/3/5/7/10/
15 kHz; three subgroups pre /post each feeding one
of two busses; phase; afl and pfl. Comprehensive
group and channel monitoring. Master and appropriate return controls for echo and aux. Comprehensive tb.
QUANTUM
Major
Quantum Audio Labs Inc, 1905 Riverside Dr,
Glendale, California 91201, USA.
Phone: (213) 841 -0970.
Largest console; may be custom built to
tions from standard ES and ER modules.
matic system of remote tape machine
linked with monitors. Allison MLH may
porated. Full details on request.
QM-8A
Compact 8/4 console for use in studio, pa, sound
reinforcement and mobile. Channels include:
balanced mic /line switch; mic attenuate; boost /cut
at 50/200 Hz and 3/10 kHz; output assign to any of
four busses or pan between 1/3 and 2/4; two es;
conductive plastic faders. Full monitor and group
outputs; tb; echo return; quad master attenuator;
submaster control, for individual output buss;
headphone cue system; large vu meters; headphone
cue system. Price $2599.
QA -3000
Flexible larger console design, based on the QA -3000
input module. Channel includes complete output
buss and associated monitor select. Hence versatility in subsequent expansion. Housing contains up
to 20 input modules, master module and ps. Add -on
to maximum of 28 input position. Comprehensive
patch bay. Up to 16 output busses available in addition to four mixdown busses. Channel controls
include mute; pan left /right, front /rear; es pre /post;
four es busses; eq ±12 dB at 50/100 Hz, 300/800 Hz,
1.5/3 kHz and 7/12 kHz; solo; hi and lo pass filter;
monitor source and mix; two cue sends; input select;
20 dB mic pad; gain trim; buss assign. Comprehensive standard group and return facilities. Price
$15 000.
QUAD /EIGHT
Quad /Eight Electronics,
11929
Vose St, North
Hollywood, California 91605, USA.
Phone: (213) 764 -1516. Telex : 662 -446.
UK: Cinesound International, Imperial Studios,
Maxwell Rd, Borehamwood, Herts.
Phone: 01 -953 5545.
Canada: Century 21 Audio, 654 King Edward St,
Winnipeg, Manitoba R3H OP2.
Phone: (204) 775 -8231.
Commercial Elec:ronics,1305 Burrard St, Vancouver,
BC.
Phone: (604) 685 -0301.
France: Studio Equipment SARL, 24 Rue de L'abbe
Groult, Paris 15.
Phone: 224- 76 -74.
Germany: Auvis Asona KG, Stollbergstrasse 15-17,
D8 Munchen 22, West Germany.
Phone: (0811) 225057.
Belgium: Delta Equipment, Lucien Velu, 112 Rue
de Calevoet, 1180 Brussels.
Italy: Laboacustica, Via Luigi Settembrini 9, 00195
RAC
Rugby Automation Consultants, 19 Freemantle
Rd, Rugby, Warwickshire CV22 7HZ, UK.
Phone: 0788 -810877.
Benelux:
Sound Techniques, Postbus 206,
Alkmaar, Netherlands.
Specialists in manufacture of smaller custom mixers,
majority less than 16 channel input. Many sold to
hospital radio networks requiring simple mixer but
with relatively specialised facilities.
As well as standard studio console arrangement
build may be sloping -front or rack mounting. Circuits available separately as plug -in modules, with a
range of 38, with application in studios, hospital
radio, schools, colleges, av systems and pa as well
as extension and modification of existing equipment.
All mixers constructed on pcb system.
Delivery times 'normally between six and eight
weeks'. Price example: 8/2 mixer with balanced
XLR in, es, treble /bass eq on all channels, ppm on
output and console -built requires around £450.
Rome.
Phone:
381
965/355 506.
Norway: Siv Ing Venum
Oslo
& Co, Boks 2493,
Solli,
2.
Venezuela: Electronica Gramcko, Av Sanz Edif
Escar, Local B, El Marques, Caracas.
Australia: Rank Industries Australia, 58 Queens bridge St, S Melbourne, Victoria 3206.
12 Barcoo St, E Roseville, NSW 2069, Sydney.
Japan: Electori Co Ltd, Mondon Building 1 -19 -3,
Kamiochiai Shinjuku -ku, Tokyo 161.
Phone: (03) 950 -6266.
Range of consoles offered based on the following
modules: NS 120 noise gate; EQ712 graphic eq;
28 compressor, selectable 2:1/4:1 ratio, level,
release, attack, variable meter display; RT6 osc, six
frequencies, LHF -20 filter set, hi /lo pass; MM71
standard line mixing module, two band eq, es and
slider, with mic gain; MM400 is MM71 plus 12 frequency eq, insert switch/led, phase, overload indicate, pad, hi /lo pass filters- designed for vca
applications, with custom variations available;
Compumix 3200 processor for automated level control using tape track as storage; EQ -312D program
equaliser, three band, twelve frequency eq. Also
available: LM6200 portable cabinet mixer, 6/2 format,
self powered.
76
STUDIO SOUND, OCTOBER
1975
specificaFull autofunctions
be incor-
RAIN DIRK
Raindirk Ltd, 33A Bridge St, Downham Market,
Norfolk, UK.
Phone
:
03663 2165/3617.
Modular mixing systems in four ranges; all may be
arranged to specific customer requirements.
Mini
Low cost mixer in 10/4 format or custom; portable,
desk or floor mounting. Up to 24/4 with eight track
switching option. Mic /line selection, channel gain,
bass, treble and mid (350/700/1.4k/2.8k/5.6k/11.6k Hz),
boost /cut; hi and to pass filters; two aux sends;
pan. Osc, vu /ppm metering. P &G faders if required.
Input channel extension units available.
Broadcast
Minimum 8/2 with extra input channels as required.
Balanced throughout. Mic /line; phase; treble /mid/
bass boost and cut; five- frequency hi pass filter;
fb and output buss selection via pan; tb; Waters
faders; vu /ppm metering.
Series II
10/2 to 36/24 with comprehensive eq and filtering.
Four aux send; direct channel output; pan; dual pot
quad system or joystick; mute grouping select; pfl;
extensive tb and master monitor systems.
Ancillary equipment includes ppm drive cards, distribution amps, disc preamps, led peak limit
indicator.
RA MKO
Ramko Research, 3516 -C LaGrande Bvd, Sacramento, California 95823, USA.
Phone: (916) 392 -2100.
Range of single channel (SC) and dual channel (DC)
mixers. All units: height 20 cm, with horizontal led
meters and touch pad controls, lighted, on all input,
solo and mute and selection switches -no moving
contacts. All solid state switching; self contained
monitor and cue amps; mono mix outlet on all
stereo consoles; cue on all channels; mute select
via plug -in jumper wires. Inputs selectable: hi /lo
level, 250 ohm balanced, or 100k ohm balanced
bridging. Prices (numbers indicate channel content):
SC -5M $605; DC-5M $742; DC-5MS $979; DC -8M
$1199; DC -8MS $1760. Two year guarantee on parts
and labour.
Series
35
Separates controls from audio functions via dc
remote control. Range includes eight channels
mono, dual channel mono, stereo, dual channel
stereo and combinations, two units parallel for quad;
'fail safe' power supply. Distortion quoted as 0.3%
or less, with -124 dBm equivalent noise on low level
channels. Prices start at $1200.
RICHMOND
Richmond Sound Design Ltd, PO Box 65507,
W 6th Ave, Vancouver, BC V5N 5K5,
Canada.
Phone: (604) 736 -7207. Telex 04 -54667 CAN BASE VCR.
1234
:
Range of theatre, mixing and portable consoles,
modular design and array as required. Visual cueing
system available.
88/816/1224
Theatre sound consoles in 8/8, 8/16 and 12/24 formats respectively. Various facilities, but all with
internal ps, pcb plug in circuitry and patch bay.
Aside from normal options, features include led
indicators showing presence of low level signal in
output channels, complementing normal vu display;
8x 8illuminated push button in /out switching matrix;
'Auto -pan' facility for semi -automatic crossfade; 12
phone jack connectors for instantaneous conversion
to computer memory capability. Prices $3630 to
$6600.
124/164/204/244 /82/122/162/202
Mixing consoles with two and four groups output;
channels variable as indicated by designation.
Channel includes cue, es, three frequency eq, fb,
input attenuator, monitor, echo return levels, pan.
Masters on all subgroups. Vu meters and led overload indicators on output or playback channel. Prices
$6500 to $10100.
M82
Portable stereo mixing systems with eight, 12 and
16 inputs with use of extender chassis. Balanced
line input, 0-60 dB attenuator, ±15 dB at 50, 1.5k and
10k Hz; fb, es, pan; cue push button. XLR input connectors, 6.25 mm output via phone jack. 74 x 34 x 11
cm. Chassis on 14 ga steel. Price $1600 and $2066
(studio); extender units $600 and $833 respectively.
SCHLUMBERGER
Schlumberger Instruments et Systemes, Centre
de Rueil, 296 Ave Napoleon Bonaparte, 92503
Rueil, Malmaison, France.
Phone:
977 92 23.
Telex
:
26649
Labophy
F.
78
OP-
MC/
MCI (Professional Studio Equipment) LTD,
21
Claremont Square, LONDON N1 91X 01 -278 2288
ME fin
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dipi
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di al
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1ï0iilNm
The JH -428 is a comprehensive, cost
effective recording console meeting all
professional standards and offering
the electrical and musical capabilities
of consoles twice its price. There are
no frills in this console, only functional
complete musical control of the mix.
The entire console has been built
small enough so that the average person can reach most of the controls
without moving. Yet, the profile is low,
creating minimum control room acoustic problems and permitting a clear
view into the studio.
The JH -428 is styled in a durable
synthetic walnut finish with control
panels in a natural sugar maple colour.
The armrest is large and well padded.
These natural colours and comfort
features minimize the tiring effect of
late night mixing sessions.
For the small studio just getting
started, every model of the JH -428
from 8 channels up comes fully wired
and tested for 28 channels so the console can grow with the studio by simply
plugging in additional modules. For
the large studio, the JH -428's modular
construction will permit full utilization
of the recording facility by minimizing
service "down time ".
The JH -16 series of master recorders is available as an 8 -track wired and
expandable up to 16 tracks (ideal for
the small studio). The JH -24 is available as a 16 -track wired and expandable up to 24 tracks, which will meet all
needs of the large professional studio.
A very useful (and some consider
essential!) accessory is the AUTO
LOCATOR 11, which can be programmed to locate any position on the
tape precisely and speedily.
The JH -110 series is the latest range
of professional recorders from MCI
These machines are ;" and +" machines
which have been designed utilising
the latest techniques, i.e. phase lock
capstan servo, D.C. spooling motor
the art logic. This
and the state of
recorder has been designed to satisfy
all European requirements.
The JH -528 series of mixing consoles designed to meet the needs of
the large recording studio has in
-
addition to all the facilities of the JH400 series very much more comprehensive mid -range equalisation extending from 150 Hz to 8.5 kHz, with a
choice of 24 frequencies in two independent groups. The console has 6
auxiliary sends which can be used for
echo fold back or sub -mixes, with panning between groups five and six and
slide -pots to control groups one and
two.
The 528 is automation ready, all level
functions control V.C.A's. There will
be available an automation -processor
together with a lock -up system enabling the multi -track machine to be
locked up to a slave recorder so that
data may be recorded on the slave
machine without sacrificing tracks on
the multi- track.
Both the JH -428 and JI-1 -528 are
available as consoles with 28 or 40
input- output groups.
They are available as 16, 24, 28, 36
and 40 channel consoles, and can be
readily expanded to a maximum of
40 channels.
77
SURVEY
Range of consoles from small portable units to
extensive multitrack configurations, produced on
large scale.
UPS
a
4000
Modular construction, based on die-cast alloy
chassis plugging into cast modular frame; console
may be tilted on its support. Modules interchangeable in situ. Electronics use ics widely; group
routing via fet switching, grouped on plug -in mother
boards; modules interconnect by mother board,
reducing wiring demands.
Any system configuration supplied using combinations of following principal modules: input, with
four balanced inputs, mic /line gain, hi -pass filter; eq,
with boost /cut, eg Baxandall characteristic :112 dB
at 60 and 10k Hz, or presence at 0.7/1.2/2/2.8/4 /5.6
kHz ± 12 dB in 2 dB steps; band pass 24 dB /octave at
100/250/500 Hz and 4/6/8 kHz; routing module;
auxiliary outputs, two es and two fb, both pre /post;
echo return with gain to main group bussing; output
amp, balanced; limiter /compressor, 'limiting function -10 dBm' with 25 dB headroom, threshold
variable over 20 dB range, variable attack and
release; fader with mute and pfl; mic tb amp with
limiter; tb return, with two amps for various pfl and
monitor functions. Automation facilities available
oriented for use in broadcast or recording environments.
SHURE
UK: Shure Electronics Ltd, Eccleston
Rd, Maidstone
ME15 6AU, Kent.
Phone: 0622- 59881.
2 Kg.
Price £76.
M67
Simple 4/1 mic mixer, 600 ohm input, fourth channel
switchable line, bridging or 600 ohms. 7 x 27 x 18 cm;
weight approx 2 Kg. Price £106.
M675
Similar M67 but with disc and line inputs; cue on all
inputs switchable; internal speaker, headphone
outlet or line feed for monitoring. £96.
SONIFEX
Sonifex Sound Equipment, 15 College St,
Irthlingborough, Wellingborough, Northants
NN95TU, UK.
Phone: 0933- 650700.
131000
portable mixer. Flat .scale fader, pfl, switched
mic /line inputs, es, balanced input and output with
XLR connectors, eq ±15 dB at 100 Hz and 10 kHz.
Separate echo return. Two vu or ppm meters switchable l ine in /out. Separate monitor feeds. Headphone
monitoring via meter select switches to phone jack.
Prices: with XLR connectors £352; with DIN £319.
6/1
B2000
10/2 format mixer designed for table top /portable
working. Channels include mic /line switching with
gain control, with balanced inputs via XLR connectors, flat scale fader, es, fb, pan, mute. Balanced
outputs for groups and subgroups. Separate
78
SONY
Sony Corpn, PO Box 10, Tokyo Airport Post
Office, Tokyo 149, Japan.
UK: Sony (UK) Ltd,
219 Bath Rd, Slough, Berks.
34611. Telex: 847122.
Phone: Slough
USA: Sony Corpn of America, 9 W 57th St, New
York, NY 10019.
Phone: (212) 371 -5800.
Europe: Sony Overseas SA, Baarerstrasse, 59
CH -6300, Zug, Switzerland. Central point for more
local European information.
MX
650
6/2 portable mixer with mie, line and phono inputs,
two panpots, twin illuminated vus, ose and headphone socket. Price £139 inc 25% vat.
MX 510
5/2 portable mixer with mie, line, phono inputs, one
panpot, two vus and headphone socket. £90 inc
Simple passive 6/2 mic /line input mixer. £33.95 inc
vat at 257;>.
STUDIO SOUND, OCTOBER
1975
(415) 391 -8776.
Four channel limiter module designed for utilisation with Tascan Model 10 mixing console. Four
channels may be independent, grouped in any pairs
or quadraphonically via two control busses. Attack
fixed 100 .'s, release fixed at 2s; compression ratio
10:1.
SPECTRA SONICS
Spectra Sonics, 770 Wall Ave, Ogden, Utah
USA.
Phone: (801) 392 -7531.
UK: (modules and components): Sun Recording
Services, 34 -36 Crown St, Reading, Berkshire.
Phone: 0734-595647.
Custom and standard consoles for recording and
broadcast purposes. Various configurations available based on modules including the following:
ose with qve select frequencies, gain; hi /lo pass
filter 40/70/100 Hz and 10/12.5/15 kHz; electronic
filter with various standard frequencies; power amp;
simple mie program eq at 100 Hz and 7 kHz; mie/
program eq ±12 dB at 50/100/200 Hz and 2.5/5/10
kHz; rotary and joystick quad pan; rack mounting
and console face compi imiters variable 1.1:1 to 100:1,
attack 0.1 us to 1.2 ms, release limiter 0.09 us, compressor 50 ms to greater than 10s.
1024-24
Available with 12, 16 and 24 group outputs, based on
input module including line /mie switch, input
attenuate, pfl, monitor submix route, two fb, eq at
lo/mid /hi, 4/5 frequencies in each band, shelf curves
at 50 Hz and 10 kHz switchable. Usual program
assign and monitor select facilities. Prices: eg 12/12
$22639, 20/16 $29123, 24/24 $32965.
SOUNDCRAFT
Soundcraft Electronics Ltd,
Range of mixers for pa and related work.
M68 Series
Simple 5/1 mixer systems, with level only channel
control; mic input on four channels, aux on fifth;
mic switchable hi /lo Z. Units may be ganged via aux
input. Various connectors available. 7 x 27 x 13 cm.
£59.20 or £76.80.
M688 Series
Stereo mic mixer similar M68 series but with two
group outputs. Four mic inputs switchable left /right
plus stereo aux input. Single pan on mic channel
four. Units may be ganged as before. 7 x 27 x 17 cm;
Phone:
844041,
25% vat.
M X8
Shure Bros Inc, 222 Hartrey Ave, Evanston,
Illinois 60204, USA.
Phone: (312) 328 -9000.
weight approx
monitor output and echo return. Two large vu or
ppm meters switched to source or tape. Headphone
through meter select switches and phone jack;
channel eq +15 dB at 100, 1.4k and 10k Hz. Additional separate units are available. Cards: mic amp;
disc preamp; virtual earth mixer; line amp; hf /If
switched equaliser; mf switched eq; three frequency
ose; ppm meter assembly; headphone amp assembly. Modules: complete channel and output modules
available in mono and stereo forms. Price 82000 with
XLR connectors £765.
5 -8 Great Sutton St,
London ECIV OBX, UK.
Phone:01 -251 3631. Cables: Soundcraft London
Stellavox,
Systems and Technology in Music, 2025
Factory St, Kalamazoo, Michigan 49001.
Phone: (616) 382 6225.
Holland: International Music Service, Energieweg
36 -37, Vlaardingen.
Phone: 35 72 22.
Sweden: Studio Decibel, Katarinavagen 18 -22,
S-11645 Stockholm.
Phone: (08) 23 34 35.
:
16/2
Sound reinforcement console built into flight case.
Available 20 and 24 channels if required. Channels
include: 200 ohm balanced mic in, XLR connector,
input attenuate, four band eq, fb, es, pan, mute /pfl
slider. Echo return channel similar, with two inputs.
Headphone monitoring fb and main groups. From
£1000; multicore systems available.
12/4 Series II
Eight track capability, 16 track monitoring, communication and lineup facilities. 105 mm conductive
plastic faders as option. Wide range metering faders
and quad panning options. Available 16/20/24
channels. From £1175.
16/8 Series II
Format up to 16/8/24; communication and lineup
facilities. 105 mm plastic faders standard. Metering
options wide. Available 16, 20, 24 channels. From
£2200. Channels include: mic /line; pad; mie; gain
4 band eq with hi -pass; two fb, one es; pfl /mute;
channel /monitor route.
Mark 5 Modular
Cost effective, wide modular system, available in
formats as required.
Mark 6 Modular
More extensive modular system than Mark 5, to be
introduced autumn.
SOUND GENESIS
445 Bryant St, San Francisco,
California 94107, USA.
Sound Genesis,
2068
Hauterive, Neuchatel, Switzer-
land.
Phone:
EC1.
USA
STELLA VOX
UK
:
33 42 33.
AV Distributors (London) Ltd,
26 Park Rd,
Baker St, London NW1 4SH.
Phone:
01
-935 8161. Cables: Cinesound, London,
NW1.
USA : Hervic Electronics Inc,
1508
Cotner Ave,
Los Angeles, California 90025.
Phone: (213) 478 -5086.
AMI
48
Five inputs for 12V AB or phantom powered capacitor mie, 48V capacitor mie, dynamic mie. XLR or
Preh connectors. Bass roll -off, bass /treble lift /cut,
pan, 20 dB pad each input. Pfl, individual post -fade
outputs. Switchable stereo compressor on two channels, limiters with led indication on each input.
Stereo limiters with led indication on master group
outputs. 880 Hz line up ose. Two illuminated ppm
meters. 8 x 21 x 27 cm, weight 4.3 Kg. Price £1095.36,
with limiter £1845.76.
STRAITA HEAD
Straita Head Sound, 7578 El Cajon Bvd, San
Diego, California 92041, USA.
Phone: (714) 465 -9997.
Custom consoles based on standard modules for
music balancing and recording. Any configuration
supplied. Typical facilities extend to multiple stereo
reinsert, led peak reading vu meters, built in crossover for multiamp operation, three band eq switchable three frequencies in each, two aux subgroups
pre /post; pad, phase, hi pass filter. Limited information received.
STUDER
Studer International AG, CH -5430 Wettingen,
Switzerland.
Phone: 056 2687 35. Telex 53682 audch.
UK: FWO Bauch Ltd, 49 Theobald St, Boreham
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series modules in console for table top or floor
standing operation. Integral pfl speaker /amp and
extensive jack bay. Built -in six -way distribution amp
and complimiters standard. Prices £4000 to £23 000.
SURVEY
Wood, Herts WD6 4RZ.
Phone: 01- 953 0091. Telex: 27502.
USA: Willi Studer America Inc,
B
Broadway,
Toronto, Ontario M4H 1E9.
Phone: (416) 423 -2831. Telex: 06- 23310.
France: 12 -14 Rue Desnouettes, F-75015 Paris.
Phone: 533 58 58/9. Telex: 24744 F audifra.
Mk
II
Intended for mobile and truck working as well as
static studio operation. 12 input channels each with:
line /mic /osc switching; phase; fine and coarse
attenuator; variable Hz hi and to pass filters; 80 Hz
+8 dB, 8 kHz ±8 dB, 0.4/0.7/1.2/2.2 /3.9/6.8 kHz +9
dB; two or four es /fb subgroups; mute. Also: filter
modules, combination hi /lo pass with variable frequency and roll -off; stereo reverb similar channel
module; and compressor/limiter ganged for stereo,
variable compression and release, compression
meter indication. Monitor selection all groups, subgroups and returns; tb. Two submasters for reinsertion. Two ppms, vu available if required. Break
points on rear mounted jack bay.
189
Quadro
For stationary and mobile applications up to 16/4
mixdown and recording. Channels similar 089, with
vu or ppm indication on each channel as well as
group masters. Two versions, with 16 channels and
16 monitor or eight channels and eight or 16 monitor.
Facilities similar 089, with corresponding extension
for quad working. Comprehensive groups selection
and quad pan joysticks on every channel.
TASCAM
Teac Corpn of America, 7733 Telegraph Rd,
Montebello, California 90640, USA.
Phone (213) 726 -0303.
:
Model
Shortly to be introduced; new low -cost portable
mixer with high specification for pa, studio or theatre
use. Based on standard mainframe with plug -in
module options giving wide variation in electronic/
mechanical configuration.
CB9066
Equaliser unit with built -in power supply. Hi and to
pass continuously variable filters, three -band eq
with variable frequency and sweep frequency selection. Price £220 per single channel.
Trident Audio Developments Ltd,
4 -10
North
Rd, London N79HN, UK.
Phone: 01- 609 0087. Telex: 264773.
USA: Pacific Recorders and Engineering Corpn,
Sorrento Valley Rd, San Diego, California
Phone: (714) 453-3255. Telex: 695008.
Audiotechniques Inc, 142 Hamilton Ave, Stamford,
Connecticut.
Phone: (203) 359 -2312. Telex: 06902.
Range of fully modular consoles permitting wide
variation in configuration, as required. One year
guarantee with each console, with full after -sales
services; same -day module repair at factory. Delivery
normally 12 -16 weeks after receipt of order.
A Series
For large multitrack studios.16 frequency graphic eq
on any channel, four independent fb, six push- selected es subgroups; quad facility, dual scale vu or ppm
metering; independent eq of echo and fb circuits;
interfaced for automated working as standard
option. Desks prewired for future expansion;
phantom mic powering; electronic stop -clock and
correlation meter standard. Prices £16 000 to £45 000.
B Series
For multitrack studios a level below those requiring
A Series desks. Identical technical specification, for
80
STUDIO SOUND, OCTOBER
1975
Westrex, PO Box 989, Beverley Hills, California
90213, USA.
Phone: (213) 274 -9303.
UK: Westrex
Co Ltd, 152 Coles Green Rd, London
NW2 7HE.
Phone: 01-452 5401. Telex: 923003. Cables: Westelcol
London NW2.
Italy: Westrex Co Italy, 65 Via Costantino Maes,
00162 Rome.
Turner Electronic Industries,
London W7 3TH, UK.
Phone: 01 -567 8472.
TPS
Co Iberica, Avenida Jose Antonio
Barcelona 7.
Japan: Westrex Co Orient, CPO Box 760, Tokyo.
Hong Kong: Westrex Co Asia, Room 1302, Luk
Hoi Tong Building, 31 Queen's Rd Central.
636,
175
Uxbridge Rd,
16/2
Portable and compact non -modular mixer series
intended for live mixing and location recording.
Channel controls include: 30 dB pad, sensitivity
variable -60 to -20 dBm on 600 ohm balanced line;
eq +15 dB at 10 kHz, +16 dB at 0.7/1.2/2.4/3.8 /5.6/
7 kHz, and +15 dB at 100 Hz; pre /post on two subgroup sends, level variable; pan; pfl; P &G type 1820
fader. Subgroups out and remaining channels are
mixed, output controlled by faders.
Mixer incorporates active filters for feeding multi amp configuration, 30 -500 Hz, 500 -4k Hz and 4 kHz
upwards (frequencies given are -3 dB points).
Additional output for stereo tape or aux pa is independent of main faders. Eq available for echo send/
return. Flexible tb system; two vu meters switchable
across all group and subgroup outputs and two
subgroup returns; also pfl selection appears on
meters when routed in.
Optional extras include multiway cable, connectors and XLR stage box; cans; variations in crossover; subgroups may be switched to provide four
group output; breakpoints (phone jack); ppm
metering. Mixer is in metal case for transport.
:
TWEED
Tweed Audio, Rosewood Industrial Estate,
Kelso, Roxburghshire, UK.
Phone : 05732 -2983.
Modular construction of custom consoles; channels
include the following: mic /line input gain; eq 60 /100/
220/330 Hz, 10/12/14/16
TRIAD
WESTREX
Spain: Westrex
TURNER
10
Series of competitively priced mixing consoles,
based on the following modules: expander; input;
tb with slate and integral 5W amp; remote control;
monitor mix with pan; quad pan with four joysticks;
headphone monitor; mic inputs balanced and
unbalanced; line amp. Prices vary 8/4 at $2350 to
24/4 at $5765. Limited information received.
11760
92121.
100 x 62 x 25 cm,
Portable
3916
Buffalo, New York 14227.
Phone: (716) 681 -5450. Telex: 91 -9138.
Canada: Willi Studer Canada Ltd, 14 Banigan Dr,
089
Limiters attack 2 is, release 0.55, limit 8.8:1
weight anprox 40 Kg. List price for
eight channel version $9400; for 24 channel version
$13000, inclusive of shipping case.
270 volts.
kHz, 0.7/1.2/2.4/3.2 /5/7 kHz
+15/18 dB; hi and lo pass filters, four frequencies
each, 18/12 dB /octave. Routing module provides
normal group and monitor switching, with up to two
each of fb, es pre /post, solo /cut.
10/4
Designed as portable mixer for recording or broadcasting direct from concert hall. Uses standard
modules in fixed frame. Facilities panel includes
aux return with pan, routing and individual monitor
gain controls. Metering vu or ppm as required.
TVCOBRAHE
Tycobrahe Engineering, 665 Valley Dr, Hermosa
Beach, California 90254, USA.
Phone: (213) 376 -8801.
Modular mixers for combinations of pa, sound
reinforcement and live recording.
MX L24(-4)
24 input console for performer use. Sealed rotary
level controls throughout; channel controls include:
pan of monitor and main group bussing; input
attenuate; three range eq, lo 50/100/150 Hz, mid
300/600/1.2k Hz, hi 2.5/4/7 kHz; monitor and main mix
controls. Dual -band limiters fully synced for stereo
operation, with hi /lo limiter frequency switch on
main outputs. Eq circuitry uses active gyrators;
power supply regulated over ranges 85 -135 and 170-
ST3000
Various input /output combinations according to
customer requirements. Modular construction.
Typical channel includes: ST3009 combining panel,
with p/b bussing selection; ST3003 channel control
panel with pre /post es /fb selector, send gain cue
push button and overload indicator; ST3001 input
amplifier, mic /line indicator, gain, 120 Hz hi pass
in /out, phase, fine gain; ST3002 eq unit, three boost/
cut zones at 50 Hz, 0.7/1.0/1.4/2.8 /3.5/4.2/5.6 kHz and
15 kHz; ST3010 fader with slider and bottom of travel
micro switch. ST3001 input amp takes mic between
-70 and -20 dB and line between -10 and +20 dB
in 10 dB steps.
ST3050
Compact mixer for small studio or location work.
Available with up to eight input channels and 1/2
groups out. Modules similar or identical ST3000;
illuminated ppm or vu metering; all components
'fully tropicalised'.
YAMAHA
Nippon Gakki Co Ltd, Hamamatsu, Japan.
UK: Kemble (Organ Sales) Ltd, Mount Ave,
Bletchley, Bucks.
Phone: Milton Keynes 71771.
USA : Yamaha International Corp, 6600 Orange thorpe Ave, Buena Park, California 90620.
Telex: 655423 YAMAHA BNPK.
Canada: Yamaha Canada Music Ltd, 1330 Portage
Ave, Winnipeg 10, Manitoba.
Telex: 35398 YAMAHA CDA WPG.
Germany: Yamaha Europa Gmbh, 2084 Rellingen
b Hamburg, Siemensstrasse 22/34.
Phone: (04101) 3 30 31. Telex: 2- 189170.
Australia: Rose Music Pty Ltd, 17-33 Market St,
S Melbourne 3205.
Telex: 32225 ROSEMUS.
E M -90
Simple six channel mixer for music use. Channels
include switchable line /guitar/mic, two groups
switchable, treble, bass, volume and reverb on /off.
Master controls for volume, reverb. Built -in rhythm
simulator with push select, and A =440 Hz reference.
£170.
EM -60
Version of EM -90 without rhythm simulator. Price
£100.
PM-200B/300/400
Simple portable music and pa mixer. Various combination facilities including bass, treble, boost /cut,
es switchable two sends on each channel; switchable
metering; hi pass filtering; five frequency eq switch able to -8/12 dB on PM-200B. Vu metering of one or
two output groups. Phone jack or XLR connections.
P M -1000
16/4 portable or studio mixer for recording or quality
pa applications. Comprehensive eq and subgroup -
ing, sliders all channels and groups. Tb, pan, input
select, etc. Metering vu on all groups, additional
small vu on two echo subgroups.
STRAIGHT TALK FROM THE COMPANY
THAT INTRODUCED THE FIRST
PROGRAMMABLE MIXING SYSTEM.
Over three years ago when we unveiled Compumix Ma whole new technology & language was thrown at
the Recording Engineer & Producer. Since then, we have all learned more about the potential of this creative
tool. From continuing research in technology and ergonomics, and direct feedback from the Engineer &
Producer, we've learned that automation systems need to be unobtrusive, operationally reliable, provide
more function capacity, and offer a separate media for the storage of the mixing information.
With the increase in the number of tracks required for music recording, including the use of synchronized multi -track machines, and a growing sophistication of the mixdown process, the demand for a more
comprehensive, yet easier to use, system became apparent.
In answer to this, we have developed our new fully- digital Compumix ' system to incorporate computer technology with external processing & display hardware.
1
It's standing in the wings & promises such exciting things
we can hardly wait to unveil it - but not before exhaustive
operational testing.
This generation of automation must perform totally: with
no compromise, if we as manufacturers are to have Industry
acceptance.
THAT'S STRAIGHT TALK FROM THE COMPANY WHO
STARTED THE WHOLE THING.
QUAD /8 ELECTRONICS
QUAD EIGHT INTERNATIONAL
11929 Vose St.
North Hollywood. California 91605
1213) 764 -1516
AmEK
Telex 662 -446
8
E
Ó RE WA1D5 8ET RENGLAND
tel 061 - 928 8688
Consoles of
the highest
specification
built to your
requirements
and budget.
We give you persona/
attention - good
delivery - after sales
service.
We have two comprehensive modular systems
Contact Nick Franks
&
8 a
Graham
non- modular series for up
to 16
tracks;
24 tracks to special
order.
Langley NOW!
81
The advantages accruing from
mixdown data storage and its later
adjustment continue to increase as
engineers become more familiar with
the new techniques. In particular,
vcas have evolved such that they
overcome many previous objections,
and resulting systems are simple and
convenient.
THE REAL MEANING is belied by the name
'automated mixing'. A much more suitable
definition would be programmable mixing.
The sole purpose of such a system is rather
clearly defined as a means of allowing the
operator, or balance engineer to program the
parameters of an audio console in a fashion
which he and the record producer feel is
required to produce the desired final result.
Such a system does not make any decisions or
calculations -hence it is not a computer.
The performance of a programmable system
may be judged on three basic parameters,
Programmable
which are:
1.
How accurately does it respond?
2. How quickly does it respond?
3. What capacity does it have for the
storage of commands?
If the system simply obeys commands and does
no actual thinking then what is the good of it?
Why does the balance engineer not just operate
the controls himself?
The answer is pretty evident to anyone who
has attempted to mix down 24 tracks of
modern music. Frequently there are simply
too many parameters to control in real time
at any given instant. Certainly, we get by.
We get a 'mix' and, more important, we make
hit records. (They also got by and made hit
records a few years ago by singing into a horn
coupled directly to the cutting stylus.)
With a programmable mixing system, the
production team is free to concentrate on the
subtleties of the mix, since changes can be
pre -programmed to occur in patterns unobtainable in real time with real people. After all,
multitrack has allowed the musicians and
singers to perform musical feats which would
be impossible in real time; so why not some
help for the balance engineer? If a singer
blows a note, he is free to punch in a correction
without destroying the rest of the music on
the tape. Should not, then, the mixing engineer
be given the freedom to correct a mixing goof
without having to re-start completely?
Programmable mixing now becomes corn parable with the recording techniques employed
in multitrack sessions. If you can get it all, in
real time, more power to you. If it becomes
necessary to mix in layers, or to punch in
corrections, or to pre- program highly intricate
manoeuvres, then do it.
After the mix is done, the performers and
producers take the mix home and analyse the
results. If they find a flaw in the performance,
they simply come back in the studio and punch
in a correction.
Without programmable
mixing, they have politely to ask the balancer
to redo all of his work (in real time) exactly as
previously. As often as not it is impossible to
reconstruct accurately the mix, just as it would
be impossible for the group to reconstruct the
entire performance.
A programmable console can give the
balance engineer the same kind of freedom
that the performers have enjoyed since the
advent of multitrack.
mixing
PAUL
C.
BUFF*
Interface
*Allison Research, Nashville
82
STUDIO SOUND, OCTOBER
1975
In order to prepare a console component for
accepting programmed control, its mechanical
movement must first be converted to an
electrical form. This action is directly parallel
with the microphone's job of converting sound
pressure into electrical signals.
If the component happens to be a fader,
either a voltage controlled amplifier (vca) or a
digitally controlled amplifier (dca) may be
employed.
Similarly equalizers, panners,
switches and any other component to be
programmed must be converted for voltage
or digital control.
A digitally controlled
switch in its most basic form would be a
relay, although solid state switching is much
more suited to the task. For achieving programmable console components, a voltage
controlled or digitally controlled element
performs the same job as its mechanical
counterpart, with the exception that it can be
controlled electrically. Mechanical parts are
still needed, but their function becomes that
of providing an interface between human
hands
and the electrically controlled
components.
At this writing, the voltage controlled
amplifier has evolved to the point of favourable
performance relative to that of its mechanical
counterpart (the gain control).
However,
voltage controlled resistors have evaded the
design world to the point where no direct
replacement exists for, say, a frequency
controlling resistor in an equalizer. Fets or
photoconductive cells will work, but their
performance leaves something to be desired
in terms of noise, distortion and linearity.
Actually it's just as well since digital control
of these components (as well as capacitors,
inductors etc) is quite simply performed and
is a much more exact science than analog
control. Fig. 1 illustrates a four -bit digitally
controlled resistor together with the resultant
values of resistance. The same sort of circuit
will work equally well with capacitors or
inductors.
Fig. 2 shows a typical utilization of a vca
as a replacement to a conventional gain control
circuit. In fig. 2b a reference voltage is applied
to the fader, where it is attenuated to the
desired degree, then applied to the control
input of the vca. With this connection, the
audio will perform the same as in the conventional circuit of fig. 2a. However, a reference
voltage output now appears which is proportional to the audio gain of the circuit.
If we now evolve into the circuit of fig. 3,
we have the basic form of a programmable
gain element. When Si is in the WRITE
position, the audio gain is controlled in real
time and the voltage which controlled it will
be entered in memory for later use. If SI is
placed in the READ position, the audio will
be controlled by the previous information,
contained in the memory.
The circuit of fig. 3 would function similarly
if the vca were replaced with a dca. The only
major difference would be that the response
would be step- approximated rather than truly
variable. The resolution between steps is a
function of the number of controlling bits. As
can be seen in fig. 1, a four -bit representation
would yield 16 steps. The employment of an
eight-bit dca would yield 256 step resolution
-
more than adequate for the purpose.
As for the conversion of the analog control
voltage to digital form, this is really not a
problem, since commercially available eight -bit
analog to digital convertors are priced as
low as $8. In the case of equalizers and such,
conversion is not normally necessary since the
controlling switches themselves provide the
necessary step function.
FIG.1 CONFIGURATION OFA DIGITALLY CONTROLLED RESISTOR
SWITCHES
A
Memory system
Now that the interfacing of the console
components is taken care of, the remaining
requirement for programmable mixing is the
memory itself. Various choices are available,
ranging from paper punch tape or computer
cards, on up to disc memories, core memories
and integrated circuit memories. A look at
the requirements will effectively narrow the
choice down to one. Since the memory must
be dynamic and must be synchronized with the
music, we can quickly rule out paper tape. The
sheer number of bits required (upwards of a
million) pretty much rules out core and is
memories. The requirements of low cost, ease
of handling and unlimited running time (bit
capacity) makes disc memories look unattractive. What's left? The same stuff the music
goes on. Good old audio tape. Its bit capacity
is unequalled, running time is indefinite, it is
easily synchronized; and it's cheap.
The most convenient form of data storage is
on the master music tape itself. Synchronization is automatic and you'll certainly never
lose the data tape. If spare tracks are not
available on the master tape, the next choice
is to carry the data on a separate recorder,
synchronized to the master. This approach,
however, will still cost you one track of music,
as required by today's synchronizing equipment. Since successful programmed mixing
requires only two tracks, the cost and convenience factor of synchronized machines bears
some investigation unless it is to be used for
purposes other than providing storage for
mixing data.
1K
"4,0*
C
0
TOTAL RESISTANCE
0
INFINITY
1
BK
1
0
lK
0
1
1
2
0
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0
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2K
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0
1
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0
1
1
0
133K
1
1
1
0
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0
0
0
0
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ON
B
0
0
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67K
14
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1
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1
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571K
1
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533K
SWITCHES
B VOLTAGE CONTROLLED CONNECTION
FIG. 2
AUDIO IN
AUDIO DUT
AUDIO IN
REFERENCE
AUDIO OUT
VOLTAGE
IN
REFERENCE
VOLTAGE
A CONVENTIONAL CONNECTION
OUT
Encoding the data
Because many channels of mixdown data
must be stored on one track of tape, some
method of multiplexing must be used. Samples
of all mixing parameters may be represented
digitally, then applied sequentially to the data
tape. If the sequencing is done rapidly enough
the result, for all practical purposes, is a
continuous representation of many channels
of information. Upon decoding, the individual
samples are directed back to the proper control
channels. The process is very similar to the
operation of a television system: what is
actually seen on the screen is a sequential
scanning of the individual elements of the
composite picture. Since the scan rate is faster
than that which the eye can perceive, we think
we are seeing a continuous, full-time picture.
Unfortunately, if we are going to store data
on conventional audio tape, we must live
within the bandwidth restrictions of the
medium. A safe data rate for such a purpose
is around 10 000 bits per second (10 kHz).
Using conventional bi -phase encoding techniques, and allowing for error correction bits,
ms per eight -bit word
a scan rate of around
is in order.
If we confine ourselves to the automation of
levels only, with perhaps a few group masters
and switch functions, a fairly practical scan
rate of around 50 ms can be achieved fairly
easily. However, even a 50 ms scan rate can
cause problems, particularly in a system where
1
the entire scan must be checked for parity
before it is released as valid information. The
problem lies in the fact that when a mix is
updated, that is to say when revisions are to
be made, all previous information must be
regenerated through the complete encode/
decode cycle, unless it is to be discarded. If
the decode cycle requires a 50 ms validation
period, this is the minimum time lost in the
If the encoder and decoder are
process.
asynchronous, an additional waiting period
averaging one half of the scan time will be
imposed. By my calculations, accumulated
delay (per update pass) for an asynchronous,
scan validated, buffered memory system would
be 1.5 times the scan rate.
For the typical system mentioned, the
accumulated delay for ten update passes would
run about 750 ms. Any attempt to program
beyond level only for more than two or three
update passes would result in intolerable
delays.
In the design of my company's present
automation equipment, we took a somewhat
different approach to the situation. The data
is encoded in quinary form (five states per bit)
rather than binary (two states). This technique
reduces the bulk scan rate to 500 µs per analog
function (an analog function being roughly
equivalent to an eight -bit binary word).
Secondly, each function is validated independently so that it is ready for re- encoding as
FIG.3 PROGRAMMABLE GAIN ELEMENT
AUDIO IN
AUDIO OUT
to*
S1
REFERENCE
VOLTAGE
IN
IN
MEMORY
WRITE
READ
OUI
soon as it is decoded. Again, the encoder and
decoder are asynchronous, so that a delay
equal to the bulk scan rate is accumulated.
Overall, the 50% savings in bulk scan rate,
plus the three -to -one savings in accumulated
delay vs scan rate, net a six -fold increase in
the number of functions for a given delay
factor. A number of consoles with complete
automation, short of equalization, are currently operating in the United States on this
basis.
There are, however, two drawbacks which
accompany the quinary code. The first of
these lies in the inherent dependency on tape
84
83
IN
PROGRAMMABLE
MIXING
machine alignment and on tape quality for
proper operation. The second drawback is its
difficulty in handling binary bits as opposed
to analog functions. (As was pointed out
earlier, analog functions are fine for controlling
levels, but binary bits are more suited to the
implementation of switch functions, equalizers
and such.)
Even if the drawbacks were overcome, we're
still faced with a problem of accumulated delays
if really large -scale programming is to be done.
Synchronous operation of the encoder and
decoder would help, but a synchronized system
could tend to become influenced by tape speed
variations. Still present would be the delay
between the movement of a console control
(an asynchronous human command) and the
arrival of the encode scan to the spot allocated
for that particular function. Another alternative would be the use of multiple data tracks,
but here again the number of tracks required
for high degrees of automation could easily
get out of hand, to say nothing of the cost and
inconvenience.
The next step
DC73.
48 .volt, cardioid.
Vocal land microphone.
For further information on the complete
,ange of Pearl microphones, contact:
Allotrope
Limited
Wardour Street, London
90
Telephone:
U.K.
AB
W1V 3LE.
01- 4371892.
Telex: 21624.
Total system
Representatives for
Let us now assume that you are given a
programmable mixdown desk and a 24 track
tape to mix on it. Where do you start? What
are the controls?
Every control which is programmable will
have at least two unfamiliar operating modes,
these being READ and WRITE.
Level
functions will probably have an additional
UPDATE mode.
When a parameter is in WRITE mode, its
operation will be the same as in a manual
console. Movement of the control will result
Pearl Mikrofonlaboratorium -
Sweden, Microphones & accessories.
HES Electronics- Brussels, TSV
series telephone balancing units,
and studio equipment.
Inovonics Incorporated- Campbell
California U.S.A., Audio electro:.
Roland Zeissler Werk Für Elektro
Mechanik -Cologne, t ,Raani
instrument
84
STLDIO SOUND, OCTOBER
One obvious thing which bears some
investigation is the fact that, in a mixing
situation, all parameters do not change
simultaneously. One might move five or six
faders at the same instant, but certainly not
all faders, panners, equalizers etc. Through
priority encoding techniques, the relatively
slow sequential scan can be interrupted in
favour of a 'priority word', which is developed
by any parameter that changes. Since only
parameters which change are effected by delays,
a system which quickly responds to changes
can have an extreme amount of capacity yet
still act as if it had a very fast scan time.
My company is currently packaging such a
system.
Using proprietary binary encoding
techniques using individual word validation
and addressing, together with priority encoding,
a capacity of over 60 000 bits (or 8000 eight -bit
functions) can be achieved, with accumulated
delays of under 5 ms, with respect to changes.
The system can operate, without decoding
errors, under adverse tape conditions, low
signal-to -noise ratios and high amounts of
tape speed variation.
As can be seen from the above paragraphs,
the method of data storage is the one really
critical determinant of system performance.
The effect of accumulated delays must be
carefully considered in any attempt to evaluate
the anticipated performance.
1975
alteration of the audio. A control
voltage or a digital representation of the
position of the control and its movements will
be available at the input to the encoder. If a
data track is connected to the output of the
encoder, and that track is recording, a record
of the movements of the control will be
impressed on the data track. Placing the
parameter in READ mode will cause it to
respond only to the information previously
encodcd on the data track. Movement of the
physical control will have no effect on the
audio.
UPDATE mode allows you to READ
previous data and to add or subtract level from
the previous data by moving the fader above
or below an INDEX POINT or no modification point'.
Assume you start by placing the console in
MASTER WRITE mode (all automation
parameters in WRITE). Assign the encoder
to data track A (one of the two data tracks).
At this point, you may 'run down' the mix in
the same manner as you would in a manual
console. When you reach the point where you
want to begin mixing, or programming, you
would place data track A in record mode and
attempt a conventional mixdown.
At the end of the song, you could place the
console in MASTER READ and listen back
to the mix. (The mix is now actually being
controlled by the instructions you entered on
data track A.) Assuming you felt that the
programmed mix was a suitable basis for
further refinement, you would now assign the
encoder to data track B, leaving the decoder
on track A. You are now free to re -write some
of the parameters, READ the acceptable
parameters, and UPDATE any parts you
might want to raise or lower. You are not
required to make the selection of modes and
leave them but rather you are free to punch
between READ, WRITE or UPDATE to
make corrections during the pass.
After this pass, you may assign the decoder
to data track B (the one you just encoded),
select MASTER READ, and listen back to
the mix and its revisions. If further revisions
are needed, you may repeat the process, this
time encoding A, while decoding B. In doing
this, you will be erasing the original information on A, but you will still have the first
revision on B and the second revision which
you just did on A.
The process of revision may continue as
many times as are necessary to achieve the
desired result, assuming you are working with
a system of suitably low accumulated delay.
If, at a later date, changes are to be made to
the mix, you may keep as much of the old mix
as desired while making any revisions which
might be necessary. At any time, the mix may
be manually over -ridden, in whole or in part,
by simply selecting WRITE mode and not
recording any data.
in a real time
Summary
In short, a programmable mixing system
allows the full flexibility to perform conventional mixing, plus the ability to alter selectively
any portion of the mix without having to redo
all of it. Programmable mixing can be an
invaluable solution to the old problem: 'The
mix is great, but the drums should have been
louder
...'
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Direct -to -disc cutting is as old as
the recording industry. While returning
completely is practically impossible,
given the automated control presently
available, a tape generation can
be saved. Noise, distortion and
transient response performances are
all improved.
Old idea -
new
twist
CARL J. YANCHAR*
KENT DUNCAN*
The mastering room
RECORDING MUSIC direct to disc was the
only method for the first half of the 20th
century. Records were of amazing quality
with the absence of tape hiss and quite
distortion -free by avoiding several generations
of tape and their accompanying electronics.
Today, technology has brought us to a place
where most recording is 24 track, a second
generation for the mix, and in some cases a
third generation to correct for differences in
azimuth. level, to accomplish massive eq
changes, or to produce effects by crossfading.
With all this ability to maintain control at
each step through the project, we have noticed
in a few sad instances the technology having
the effect of making the music mechanical.
With the advent of automation for level control,
somehow the music almost seems to take a back
seat to the amazing paraphernalia surrounding
the engineer and producer in a mixdown
session. While all of this equipment can be
very useful as problem solvers, we can't help
but step back and shout `Stand up for the
*Kendun Recorders, Los Angeles
86
STUDIO SOUND, OCTOBER 1975
music !'
Buried as it is under automation, limiters,
equalizers, digital delay, time cubes, several
echo devices, phasers, de- essers, four track tape
delay, 24 channels of audio (many of them
electronic), sophisticated monitor racks that
dwarf consoles of 20 years ago, time limits,
and egos, somehow little of music seems a
little lost. But far from being an indictment of
the modern music business, this article is only
a call to switch some of that junk off and let
the music flow. In the process of doing just
that, we have come across an old idea revisited
-that of direct to
disc recording.
Automation, babe in the woods that it is,
has come into the fore of late and has become
known as the panacea to achieve the dream
of the producer without great trauma for the
engineer and the album budget. Recording a
live group direct to disc today is nothing but a
special circumstance. There have been records
recently where the original recording was direct
to disc but the attempts have been far too few
and often too costly.
All the elements and methodology developed
until now not only makes this feat technically
difficult but artistically next to impossible. So
given that we are locked into multitrack recording and overdubbing, the only possibility for
proceeding direct to disc is forward from this
point. Before automation, this would have
been a nightmare, but with it and a little
planning, it is a definite possibility.
Why bother? Consider what you would be
doing. You would bypass:
I. Two tape machines -the mixing machine
and the playback machine in the mastering
room with their differences in flutter and
wow, signal to noise, frequency response and
head characteristics (especially if they are of
different manufacture as is often the case).
FIG.
I
band.
Using this simple but effective setup, we feel
significant steps have been made in improving
signal to noise, distortion, and, most of all,
transient response. Records are now in release
on Columbia Records using this system, and
extensive on -going experimentation and demos
are being done with the Isley Brothers on
T-Neck Records and with Stevie Wonder for
Motown.
ARRANGEMENT FOR DIRECT-TO -DISC MIXDOWN
OUTBOARD
EDWPMENT
LATHE
24 TRACK
CUTTER
HEAD
CORSOLE
TAPE MACHINE
VA
IPITCH
AGONY COLUMN
CONTROL INPUT
TAPE
SYNCHRONISES
ADVANCED
L TRACX
TAPE MACHINE
(CONTROL MIX)
Most of the time, two sets of noise
reduction equipment; once again, the set
used for mixing and the set used for playback. These are usually different units with
slightly different characteristics. (We solve
this at Kendun by moving Dolby cards with
the tapes.)
3. One disc mastering console with its
equalizers, filters, low- frequency crossovers
and all the other goodies to help bad mixes
make it to disc.
4. Overall limiting and equalization when
the problem is just on one particular
instrument.
5. Two or more monitor systems with
different speakers, voicing filters and room
acoustics.
6. Most problems (and that covers a lot of
ground) that should be better corrected at
the source rather than while mastering.
All this is nothing to sneeze or shake an
alignment tool at. But what does it involve?
Today's stereo records require the use of a
variable pitch and depth system, usually for
singles and always for albums. Normally, all
this entails is adding a second playback head
electronics to the mastering machine and some
provision for providing the correct amount of
preview distance. There are several possibilities:
1. Four, eight, 16 or 24 track preview head
and duplicate sets of electronics in the
mixing console- obviously far too complicated and expensive.
2. A digital delay line for the audio. This
approach has been used in normal mastering,
as proposed by the late Howard Holtzer.
This method seems reasonable for Scully
lathes but today would be far too expensive
to provide the delay necessary for the
Neumann system. Also, the idea of delaying
the audio signal bothers us on the surface,
for we then enter another area of possible
distortion and trouble.
3. The third alternative brings us to the
setup at Kendun. We utilize a custom
Automated Processes console with extensive
audio modifications done at our own studio.
Using a 3M 79 24 track locked through an
API Mini -mag to a 3M 79 four track, we
lay a mix on the four track. We then advance
the four track up the necessary 1.1 seconds
2.
or 0.84 seconds to provide the correct
preview signal, and have easily overcome
the obvious 24 to disc problems.
Other problems, such as eq changes, or
control of other outboard gear, are accomplished using additional automated input
modules which seems reasonable as a well
recorded album (and a 24 to disc album always
is) has little if any eq change from band to
How do you deal with the novice or idiot
producer who must make a huge show of being
in charge? The worst problem is inept fiddling
with the remix channel faders, which usually
provokes disaster at a crucial point in a
complicated mix when such a body tries a
subtle readjustment but overcompensates.
Customer relations meaning business, the
studio decided to install a fine adjustment
producers mixer
set of rotary gain pots not
as fierce as the channel fader, but enough for
limited artistic control.
It worked brilliantly. The engineer could
concentrate on his mix and its cues, and the
producer was very happy, busy with his subtle
variations. It's worth trying, for it's very cheap.
You don't even have to wire the back of the
pots
.
-a
.
.
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Call or write for
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.
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(212) 541-5900
Audio /Video
87
Computer assistance of mixing
functions has developed
largely along voltage controlled
lines, with attendant
problems of distortion and level
update. However, a
mechanical, servo -driven console
system can be designed
to eliminate many such
objections.
Computer
assisted mixing
DEREK TILSLEY*
*Rupert Neve
88
& Co. Ltd.
STUDIO SOUND, OCTOBER
1975
NOT THAT LONG ago recording music in
a studio involved arranging the artists to
perform in front of a large horn, and the
sounds they generated had to be balanced by
their positions in the studio and, indeed, by
the loudness that the players produced from
their instruments. The sounds were gathered
by the horn and fed directly to disc -cutting
apparatus. Electronic aids soon came to the
assistance of the music recording engineer and
microphones could be arranged within the
studio and the electrical signals mixed and fed
directly to disc- cutting equipment.
As recently as the 1960s, sound mixing
consoles were extremely simple, many of them
comprising a handful of large black rotary
knobs and very little else. The advent of
stereophonic recording meant that the sound
mixer had to be more complicated. At first
there were two outputs. Very soon thereafter
three outputs were introduced, representing the
left, right and a centre signal. This led the way
to the concept of multitrack recording.
I think it is wise to analyse the reason for
the rapid growth of multitrack recording from
four to eight to 16, and these days, to 24 and
even 30 track recording. (In the latter case,
I refer to synchronising two 16 track tape
recorders together.)
Before multitrack recording, it was necessary
for the balance engineer and producer to
organise and rehearse their performers as well
as the balance engineer's actions on the sound
control console, so that a complete piece of
music could be recorded at a stretch. Any
complicated manipulation of the sound mixer's
controls had to be perfectly executed or a
retake was necessary.
With the advent of multitrack recording,
music from the studio could be recorded on
many different tracks of a multitrack tape
recorder. In the simplest application of multitrack tape recording, the musicians can be
dismissed while the balance engineer spends as
many hours as necessary adjusting the balance
of the sounds, the degree of reverberation, the
amount of equalisation and whatever other
corrections are at his disposal through the
modern console and its accessories. Another
important advantage of multitrack techniques
is the ability to build up the tracks one by one
if necessary. There are many standard instances
of backing tracks being laid in one studio,
further instruments added in another studio,
and the voice of a star singer recorded in still
another.
Expanding mix
As the demand for an ever -increasing number
of tracks has grown, the job of mixing down
the prerecorded signals has become a mammoth
task. Consequently, many balance engineers
wish they had six pairs of hands and an
infinite memory enabling them to recall, for
example, the exact fade up and fade down of a
particular set of instruments required for the
finished product. There are also functions in
the main studio control room which, because
they are tedious and repetitive, lend themselves
to the application of modern technology to
assist the balance engineer. The primary
object is to enable him to concentrate on
producing an artistic result without being
bothered with the electronics and mechanics
surrounding his operation.
It becomes clear, therefore, that what is
required is the application of digital or memory
techniques to relieve the balance engineer of
the repetitive and dull jobs in the control suite
-in effect, to provide him with additional
hands and additional memory. It is vitally
important to avoid increasing the number of
controls or detracting in any way from the
immediacy of the artistic balance he is trying
to create. Sound mixing consoles already have
an impressive array of knobs and faders, and
the balance engineer does not require further
complexity in his work. The sound mixing
console, and in particular the faders used on
it, have been evolved after years of experience
and represent the best known method of giving
the balance engineer easy control of the level
of each channel.
Control and indicator
The fader, normally linear, acts both as a
smooth control and as an indicator of the
relative levels of the signals being controlled.
It is desirable that any assistance given to the
sound balancer should retain these faders (as
familiar to the sound balance engineer as the
keyboard is to a pianist) and retain their
function of being both control and an indicator.
At the present time, there are several systems
on the market employing digital and memory
techniques to help the sound balance engineer.
These generally use a voltage controlled
amplifier to vary the level of the sound signal
in a given channel of the sound mixing console,
with the traditional fader being employed to
produce a dc voltage to control the vea. The
dc voltage converted to digital form can then
be recorded on to one or more tracks of the
tape recorder, so that in replay this voltage
can be regenerated to operate the voltage
controlled amplifier bypassing the fader.
These techniques, although a praiseworthy
attempt to help the balance engineer, have some
acknowledged inherent defects. It is technically
not difficult to provide a memory system which
will reproduce the settings of controls on a
sound mixing console. What is more difficult
is to provide a ready and easy method by which
the balance engineer can update the memory
with further information, without imposing on
him the need to operate or observe more
controls or indicators than already exist on his
sound mixing console. Because of the techniques currently available, it is not possible for
the fader to retain its function as both a control
and, at the same time, an indicator. Furthermore, when the balance engineer wishes to
listen to his first attempt, the memory (information recorded on a track of the tape recorder)
operates the level controlling elements directly
and therefore a problem exists with immediate
update of fader levels.
Of the existing systems there are basically
two solutions offered. In one, the fader can
be used to apply additional correction to the
signal directly and the system computes the
final level by adding together the level previously recorded on the memory to the further
correction now applied. This has the disadvantage of completely losing the usefulness
of the fader as an indicator of the level of that
particular channel of the console.
The other solution to the problem of the
operator updating the settings of his controls
by memory is to provide indicators to allow
him to move the fader control to a coincident
position with that recorded on the memory,
and then allow the operator to press pushbuttons to change over the memory function
from replay to record as far as that control is
concerned. This procedure is bound to have
an inhibiting effect on the operator's ability to
update his signals instantaneously.
An additional inadequacy of current memory
techniques in assisting the sound balance
engineer is the limitation on the number of
attempts that he can make at a given balance
which can be recorded in the simple memory
system using tracks of a tape recorder. Let me
emphasise again that I consider the most
important problem to be devising a system of
memory help for the sound balance engineer
that enables him to see instantly the position
of the controls on his sound mixing console
and allows him to update them with equal
ease, whether the console is under memory
control or being operated without the memory
in service.
A solution to these problems can be found
by harnessing a computer to the sound mixing
console and utilising electromechanical controls
driven by the computer. The computer is
'synchronised' (an audio engineer's term) to
the multitrack recording by the use of a time
code recorded on one track of the multitrack
tape recorder. This system means that only
one track of the tape recorder is sacrificed.
The computer provides, within reason, as many
memories as any reasonable sound balance
engineer could want. The electromechanical
controls ensure that the actual control always
positions itself visually to that level previously
dictated by the balance engineer and recorded
by the computer. The motor -driven controls
which can be linear faders or rotary functions
have a separate control track which is interfaced
to the computer and provides positional
information which is used to control the drive
motor.
Updating any control
To update any control, the balance engineer
would merely reach for that control and move
it to an alternative position. A proximity
switch would tell the computer to record the
changed information and the balance engineer
does not have to operate or observe any
additional controls or indicators. This will
then give the engineer the artistic facility for
instant update of previously memorised
attempts at his mixer without mechanical
factors inhibiting his artistic interpretation.
Critics of motor -driven controls will no
doubt argue that this is a step backwards into
a previous decade of technology. Electromechanical devices have in the past a relatively
poor reliability record compared to all electronic systems. But recently the development
of such devices has enabled them to reach a
very high pitch of reliability.
Where such
devices are appropriate to provide the best
possible operator convenience, engineers should
not object to their use.
The real advantage of motor -driven controls
can be emphasised again with reference to the
well -known auto -pilot system in an aircraft.
When the aircraft is under the auto -pilot
control, movement of all the control surfaces
and throttles are performed automatically.
However, whenever the pilot needs to take
manual control instantaneously, all his control
levers and knobs are in the correct position at
the instant he takes over. A further source of
unreliability could be the utilisation of clutches
if these were incorporated to restore the low
friction feel of the controls under normal
manual operation. In practice, the additional
load of a modern motor on to, say, a fader
during non -memory assisted operation provides only a smooth damped feel; the only
possible disadvantage is a limitation on the
maximum rate of movement of the control by
hand.
Spot the
Difference
Additional distortion
Although modern voltage controlled amplifiers produce considerably better performance
than a few years ago, it cannot be denied that
additional distortion and noise is introduced
into a sound mixing console employing these
techniques. The conventional fader with, say,
a plastic conductive track is undeniably the
most noise and distortion - free method of
attenuating an audio signal. The use of servodriven faders maintains this distortion and
noise-free fading.
The use of a computer opens the doors to
additional assistance in the control suite. For
example. it is highly desirable that the tape
recorder transports used in the mixdown be
controlled by the balance engineer from the
console itself via the computer. The balance
engineer can then, for example, mark a given
point on the tape at the beginning, say, of a
passage with which he is having difficulty.
Pressing a single recycle button on the control
panel will ensure that the multitrack tape
recorder always `rescues' itself back to this
particular point, and the balance engineer can
make attempt after attempt on a given tricky
passage very quickly with his tape recorders
under remote computer control.
Although it is outside the scope of this
article, the computer can be harnessed to
perform any function in the whole music
recording control room which has to be
performed under the control of the balance
engineer or in synchronism with the music.
For example, changes in the reverberation time
of echo plates during the course of the music
can be memorised and recalled by the computer. A further advantage offered by a computer
is the ability to control all the switching
functions in a sound console through its
system.
This removes the necessity
TYPICAL
TEKNIK SM2
STEREO
STEREO
MASTER
MASTER
RECORDER
at around
RECORDER
at *£1,750.00
£3,000.00
complete
Wow
a.
Flutter
Et
Flutter
less than 05%
(Typically .02% at
15 ips)
Start Time
Start Time
less than .5 sec
less than
Frequency
Response
Frequency
Response
Erasure
Erasure
75dB
75dB
Full Servo Tension
Noise
60dB below 320
Full Servo Tension
Noise
60dB below 320
nWb /m at all speeds
Servo Controlled
Capstans
with panel operated
or remoteable
varispeed
Electronic Tape
Timer
Switchable
40- 18KHz+2.OdB
nWb /m
Servo Controlled
Capstans
for
hundreds of push- button controls. One of the
computer's standard routines could be the Electronic Tape
setting up of a console at the beginning of any Timer
mixdown session.
The computer
In addition to its capacity for many memories
and its versatility in performing many functions,
the computer has the advantage in that its
instructions and its `memory' can be transferred
readily to a data storage device, eg a floppy
disc. For those unfamiliar with computers, the
floppy disc looks like a 45 rpm record in its
sleeve and is thus flat and easy to store. All
the information required for a complete
mixdown can therefore be stored on such a
floppy disc and placed with a multitrack
master tape in its normal box. Some engineers
will see in this facility the possibility of disc
Wow
less than .05%
.3
sec.
40- 20KHz-
2.OdB
NAB /DIN
equalization
metering plus
L.E.D. peak level
indicators
V.U.
*
U.K. Trade Price
KlnrkTeknikLtd
Summerfield Kidderminster
Worcestershire DY117RE
Tel Kidderminster 64027
96
89
lcUlcIAí.
*
For photos of Soundcraft and A/len and Heath see page 63.
SOUNDCRAFT TWELVE INTO FOUR
RECORDING CONSOLE
Angus McKenzie /Tony Faulkner
Distortion Measurement
Line input to group output terminated with 600 ohms.
Test frequency 1 kHz, +10 dBm input level: at +10 dBm output level,
thd is less than 0.02%; at +18 dBm output level, thd is less than 0.07 %.
Balanced 200 ohm input to group output terminated into 600 ohms
at 0 dBm. Test frequency 1 kHz: -70 dBm at 10 ohms source impedance,
thd immeasurable below noise (0.1"o). -50 dBm at 10 ohms source
impedance, thd immeasurable below noise (0.02,;). 0 dBm at 100 ohms
source impedance, thd less than 0.03 %. -10 dBm at 200 ohms source
impedance measured at 50 Hz test frequency, thd less than 0.16 ",,.
Limiter Operation
dB of limiting at 0 dBm output level, thd less than 0.2 ",..
10 dB limiting at +10 dBm output level, thd less than 0.9 ,,.
insertion of a jack into the input socket, which breaks the mic
input. The gain control did not exhibit any irregularities in its law
although, as discussed later, there were other problems when it was
set fully counter -clockwise (ie at minimum gain).
The input impedance at 1592 Hz of the microphone input was
checked, which measured as an average figure 675 ohms
rather on the low side (around 1k or so would give
safer matching) but unlikely to cause any serious aggravation.
The impedance was well maintained over a range of gain settings.
On the line input, the modulus of impedance at 1592 Hz was 33 kO,
which is again satisfactory. At kHz, the maximum input voltage
before the clipping of the first stage was as shown below:
-
1
Mic Input at Max Gain
-56.25 dBV
Mic at Min Gain Line Max Gain Line Min Gain
-42.5 dBV
+0.25 dBV
+16.25 dBV
10
'
Noise Measurement (wide band)
At maximum mic gain (94.5 dB) with input terminated to 100 ohms source,
signal to noise ratio is 34 dB. At 70 dB mic gain, signal to noise ratio is
58 dB. At any
than 80 dB.
line gain up to about
30 dB, the
signal to noise ratio is greater
Frequency Response
Measured with a 1k ohm output load or greater, the -1 dB points are
20 Hz and 20 kHz (line) or 17 kHz (mic). The corresponding
dB points
are 10 Hz and 35 kHz (line) or 24 kHz (mic). At 600 ohms output load, the
bass response degrades to -1 dB at 40 Hz and
dB at 20 Hz. The
-3
-3
manufacturers state that the output stage of the mixer will satisfactorily
operate into 600 ohms load but performs much better into higher bridging
loads, achieving outputs at clipping of +20 dBm.
Although these results are considerably better than many
competitors, the Soundcraft might benefit from the inclusion of a
switchable input pad; a simple passive 20 dB attenuation operating
both on mic and line would make the input headroom much better
-and incidentally, would make it superior to several expensive
'household name' consoles, where very high microphone outputs
sometimes mean that a line input has to be used for a microphone
output. The use of extensive equalisation not surprisingly reduced
the input clipping margin, and a switchable 20 dB pad would also
get the user out of trouble in this situation.
The equalisation section of the input circuitry operates over
four separately controllable ranges, as shown in the two graphs.
Treble and bass are self-explanatory offering =15.5 dB / -16 dB at
15 kHz and H- I8 dB / -18.5 dB at 50 Hz. The treble control does
FIG.1
Meter Options
Manufacturer: Soundcraft Electronics Ltd, 5 -8 Great Sutton Street,
London EC1V OBX. Phone: 01 -251 3631/2/3.
Price (UK): £975.
US agents: Verne Wandell, System and Technology in Music Inc,
2025 Factory Street, Kalamazoo, Michigan 49001, USA.
Phone: (616) 382 6225.
Price (US): $3450.
I
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is called for.
We start with the performance of the input channels. With
channel and group faders set to maximum and the pan -pot hard
over in one direction to feed one output group only, the maximum
microphone voltage gain available was exactly 100 dB, which could
be reduced to 37 dB by means of the continuously variable
sensitivity potentiometer at the top of the channel controls. With
identical channel and group fader settings, the line voltage gain
was continuously variable from 80.5 dB to 20.75 dB by means
of the same control. The line input is selected on immediate
90
STUDIO SOUND, OCTOBER 1975
CM
MMMIMIMM:II
MIMMMIII
MMIII
LEVEL
FIG. 2
MMiiï ii
MMCM'MMCII
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PAPER SPEED:
BASS
MMMMIMM"II
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/MIN TREBLE,MAX /MIX
MMM:CMMM:II
MMMMIMMM I
.... =....
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Ch 10
THE SOUNDCRAFT 'Twelve into Four' is again a very modestly
priced mixer when one considers the facilities available. There are
12 input channels plus an echo return, four main output
groups plus one echo send and one foldback group, and a 4/2
monitor mixdown facility. All of the microphone inputs are via
standard XLR type connectors, and are balanced; the other inputs
and outputs are all unbalanced and employ Type A PO jacks.
The mixer is not constructed in removable modules, but the
savings in manufacture (avoiding expensive connectors and racking)
have clearly been put to good use in the overall design and
performance of the desk, which does not suffer from many of the
'bugs' one finds on other low -price mixers.
The mixer is very light indeed
feature often apparently ignored
by many manufacturers of 'portable' desks -and may easily be
carried by one person without fear of personal injury. It is 1m wide,
65 cm deep and 14 cm thick, making it ideal for taking on
recording locations or for public address work where high-quality
EQ CHARACTERISTICS.
itll:lite
____..I. ....
II
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---...
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Ch10
Gpl
RECTIFIER: RHO
.
Wr SPEED
31.5mm /s
M:ÇIMMMCM:
MMI-MM....
--....--..... -MM....
MMMMlllll
PAPER SPEED:
CMMM:::
1Omm /s
ZERO LEVEL:
-10dtV
M;:B::IGCCCM::C
CMMB:II
20
50
100
200
500
FREQUENCY
000
NI
Hz
2K
5K
10K
Group fader at maximum,
routing buttons in, y axis fsd _
-50 dB at 10 dB /div x axis fsd =500 Hz
at 50 Hz /div. FIG. 5: test conditions
as fig. 4 but after modification.
FIG. 3: Limiter function.
dB limiting at 1 kHz, 500 ms
release, 4 dB threshold. FIG. 4:
10
spectra/ display depicting power -
line harmonics before modification.
Above. FIG. 3
not have a shelving characteristic and is still rising at 20 kHz
( -I 17 dB at max)-on the other hand, the bass control does shelve
at around 50 Hz.
The two other tone controls are titled `Middle' and Presence',
as can be seen from the pen -chart recordings; the Mid operates
around a centre frequency of 300 Hz (+12 dB) and the Presence
around a frequency of 3 kHz (+13 dB /-14 dB).
Moving down the input channel controls, next are the foldback
and echo -send gains. These feeds are, surprisingly, both permanently
wired pre- fader, although presumably either or both could be made
post -fader fairly easily for those who prefer it that way. Below
these two controls is the pan -pot, the output of which can be routed
by means of two square yellow knobs (unfortunately not labelled
on the review sample) to pan between groups one and two, or
three and four, or both. The law of the pan -pot had no particular
problem although there was a fairly sudden jump from extreme
left, say, to half-left. The pot loses 8 dB in its centre position as
compared to full left or right, and this is not altogether an optimum
value. In between the panner and the track routing, is a toggle- switch,
which has positions for channel on, channel off, and a biased
position of pfl which appears on the monitoring when the
appropriate switching on the monitor circuit is applied, and can
also be displayed on the metering by suitable switching.
At the bottom of the input module is the slider fader, which is
a high -quality short travel type made by Ruwido-the positions
of the slider are calibrated approximately in decibels at 0, 5, 10,
15, 20, 30, 40 and 00. This calibration was checked on several
faders, and was maintained within 2 dB or so, apart, of course
from the bottom which was 78 dB at kHz.
Final measurements relating specifically to the performance of
the input section were those checking noise of the microphone
amplifier. Sensitivity (gain) control was set to give an overall
voltage gain of 80 dB between the balanced microphone input
and the main group output. With the channel slider fader at
maximum, and the group fader at 10 dB, the equivalent self-noise
when the input calibration tone (1 kHz 200 ohm source) was
removed and a 200 ohm resistor was substituted was 129 dBV;
in more familiar terms, 126.8 dBm (although the use of dBm is more
than dubious since the characteristic impedance is not 600 ohms)
with the bandwidth limited to 20 Hz -20 kHz. This reading was
found to include hum from the power -supply, and when the
bandwidth was further limited to 200 Hz-20 kHz the figure
improved to 131.6 dBV ( -129.4 `dBm'). Excluding the hum
pick -up (detailed later) the noise performance of the microphone
preamplifier is clearly very good indeed.
The mixer includes a built-in mains power -supply incorporating
a toroidal type mains transformer- although this precludes the
need to carry a separate power-supply around with the desk, the
advantage is in our opinion overruled by the presence of hum
which manifested itself on several occasions during the tests. We
contacted the makers, who were most helpful, and also suggested
that part of the trouble might emanate from the lack of any
regulated power supply on the particular sample supplied to us.
We noted 50 Hz breakthrough in the form of rather nasty sidebands
either side of a 1 kHz fundamental which we employed for our
distortion measurements later discussed (these sidebands, ie 950 Hz
and 1050 Hz, were only 52 dB) on an output of +1.8 dBV
(1.23V rms, ppm5, 0 vu). Another occasion was when we
investigated hum on the group outputs with the main faders at
maximum -with none of the routing buttons punched, the 100 Hz
was 80 dBV which is satisfactory, all things considered. However,
selecting the relevant output group by means of the push- buttons
on the input channels brought the figure up the more channels one
routed through, until a shocking figure of 58 dBV was attained.
Purely the action of depressing the button added the hum, without
turning any channel on, bringing up any channel -fader or pan -potting
to the relevant group. Apart from this hum breakthrough
associated with the routing, the basic line- output hum and noise
were satisfactory, with expected addition of some noise with the
92
limiters switched in.
1
Above: FIG.
4
Below: FIG.
5
91
SOUNDCRAFT 12/4
Before moving on to our complete measurements on the output
section, we should mention the echo -return channel. This is in effect
a 2 -1 mixer for two echo returns which then feeds the main
output groups via equalisation and routing similar to that employed
on the mic /line channels. Therefore, although there are two
echo -returns, the channel is mono, and if you want stereo
echo -return, you must use two of the main mic/line channels. To
the right of the echo -return department is the foldback group
main (rotary) fader, the monitor switching to route foldback, pfl,
or the output of the monitor mixdown to the main stereo monitoring
outputs. There is a main monitor gain control but surprisingly
no main echo -send group gain pot, which could prove an unfortunate
omission with no quick way to correct the level being sent to the
reverberation device if it starts clipping, for example.
The monitor output appears on two sockets on the mixer; one at
the front for headphones (adjacent to the monitor gain control) and
the other at the rear of the panel for feeding to the monitor
amplifier. The rear output is run at 12 dB or so lower level than the
front socket by means of a passive attenuator, so that headphone
volume is high enough without having continually to juggle with
power amplifier settings.
Although the philosophy behind this approach is clear, it
degrades the performance of the power-amp feed by the necessity
for winding up the gain of certain varieties of power amplifier in
order to avoid running into clipping of the attenuated monitor
signal. The 12 dB pad means that the rear monitor socket will
only give +5 dBV before clipping (ie 1.8V), and there are
circumstances where this might not be enough.
All of the other group outputs (main groups, foldback, echo send,
front panel monitor) gave sufficiently high output levels before
clipping. The front -panel monitor gave +17.5 dBV and all of the
other groups gave between +19 dBV and +19.5 dBV into
open circuit, with the exception of main group two which went into
a curious oscillation 1 dB or so below clipping making its
maximum output +18 dBV. The output for clipping of the main
groups into a load of 600 ohms was degraded by 3.5 dB.
While measurements on maximum input and output voltage
swings were being carried out, a problem was observed with the
input channel gain potentiometer, as mentioned earlier. With the
gain -pot set fully counterclockwise (ie minimum gain) there was a
mysterious breakthrough of a high level input, eg 3V or higher.
This breakthrough was only apparent with the sensitivity control
right at minimum, and appeared at various points on the mixer
whether or not the relevant channel fader was up, or routed
through. We would associate this sort of problem with earth routing,
and could be alleviated by holding the bottom of the potentiometer
up (electrically speaking) by means of a small value fixed resistor
in series selected after some experimentation. The breakthrough
was not of pure signal, but of `spikes' corresponding to peaks of
the input waveform -particularly noticeable on the monitor output.
The measured harmonic and intermodulation distortion were
very good. At an output of 0.775V rms the second harmonic
content was 0.013 % (-78 dB) with third and fourth harmonics
each below 0.003 %. Loading the output with 600 ohms did not
worsen the distortion to any significant extent, although the output
level dropped 0.5 dB. With 2.5V output at 1 kHz even into 600 ohms,
distortion was still only 0.02% second, and 0.01% third and fourth
harmonic contents. At 7.75V out into open circuit (ie 1.5 dB or so
below clipping) the second harmonic distortion was as low,
indicating that the output circuitry has clearly been most carefully
designed. However, pure harmonic content is not the whole story,
since 50 Hz sidebands at only -52 dB were visible as a result of the
inadequacies of the internal power supply mentioned previously.
The intermodulation distortion of the mixer was also found to
be very good using a 4:1 mix of 50 Hz and 7 kHz (SMPTE). At an
output corresponding to ppm5, 0 vu, the im was 0.01 %; 5 dB
higher it rose slightly to 0.024 %; at a level a further 5 dB higher
(ie on the endstop of the ppm) it was 0.068 %; 1.5 dB below
clipping it was 7.75%.
The mixer supplied for this review included four ppms rather than
the standard vu meters. This option, although it inevitably costs
a bit more could be well worth paying the extra, although many
users might prefer an alternative calibration of the meters. One
92
STUDIO SOUND, OCTOBER 1975
often hears criticism from engineers who are used to working with
vu meters that tapes recorded using ppms are frequently
under -recorded. This is because ppms are very often set up such
that a ppm reading of six signifies a recorded flux level of
320 nW /m-in practice 4 dB or so above Ampex Operating Level,
and corresponding to the reference level at the top of a BASF,
EMI or AGFA test tape. For our own recording sessions we
regularly employ ppms but prefer to make ppm 6 ( +4 vu)
correspond to a level 4 dB higher on the tape which is a more
realistic peak recording level with the latest generation of high
output tapes -and also still leaves sufficient headroom for
transients and unexpected peaks 2 dB or so higher.
The law of the ppms was checked through and found satisfactory,
ie within dB of what they should show, with the exception of
meter two which was set to over-read by approximately 0.5 dB
in addition to any minor law errors. The meters under-read 4 dB
for a tone burst of 4 ms duration, which is within specification.
With one or two exceptions, the performance of this mixer
impresses
does not set out to give more than it can afford to
do properly within the tight budget of a low -price product. It
lacks the refinements of phantom powering, jackfields, talkback,
internal oscillator, fully balanced inputs and outputs (though
mie is balanced) -but the facilities which are there are good. The
power supply is the biggest shortcoming, and any possible input
overload problems (such as when using a lot of eq on mic /line,
or when there is a high level microphone input) could be avoided
by the inclusion of a simple switchable passive 20 dB attenuator
pad in the input circuitry.
Monitoring is flexible enough for most applications of such a
mixer, and the foldback (fed from input channels, output groups or
off tape) as set up with the individual controls would do the job
for which it is intended. The main output groups also include
limiters (one each) which regrettably could not be linked for
image stability in stereo or quad operation. The photograph shows
the characteristic of the limiter, with a setting of 500 ms release
and 4 dB threshold-the limiting was 10 dB and the photo shows
before and after limiting a tone burst of kHz.
All of the output impedances were satisfactorily low at 50 ohms
or less, with the exception of the rear monitor socket which was
higher, presumably on account of the 12 dB attenuator.
With one or two modifications, this mixer will be very attractive
for those who cannot afford to buy a `household name' desk, and
is likely to satisfy musicians and engineers operating on a small
budget who require a very basic console and can live without
luxuries to which one so easily becomes accustomed with more
comprehensive equipment.
-it
1
Postscript
On completion of the basic review, Soundcraft decided that they
would like to install a modification to the review sample. This was
carried out, and made a remarkable improvement to the measured
hum performance of the desk. Apparently this change has now been
introduced in production at their factory and all future mixers in
this category will be similarly improved.
Hum on Group Two
output, fader at
max and all routing
buttons depressed
50 Hz
50Hz
100Hz
150Hz
200Hz
Before Modification
-77 dBy
-58 dBV
-78.5 dBV
-75 dBV
After Modification
-81 dBV
-75 dBV
-84 dBV
-91.5 dBV
sidebands of
kHz test signal
(ie 950 Hz and
1050 Hz) as during
1
distortion tests
-52
dB
-85 dB
1
We also understand that several further modifications will be
made on forthcoming production runs. A switchable passive
attenuation pad will be provided to improve the input headroom,
and the input gain potentiometer will incorporate an additional
fixed resistance to prevent the breakthrough at minimum gain
setting. Phantom powering for capacitor microphones can also be
incorporated on request, obviously at some extra cost, which many
users will find a convenience. See Letters p32-Ed.
Within 2 years, 4- channel sound will be the rule.
Sansui QS system puts you 2 years ahead.
Now your listeners can enjoy the extra
depth of 4- channel sound with the minimum
of 2-channel conversion costs on your behalf.
Thanks to the Sansui QS Regular Matrix
System. Now available forte first time in the
United Kingdom.
Keep your equipment.
The Sansui QS 4- channel system is used
with all current stereo transmitters/receivers,
cutting equipment and hardware. So there's no
need to upgrade. The listener only requires a
4- channel receiver and 4 speakers to obtain
astounding quadraphonic effects.
preserved. In fact it gives better stereo perspective than conventional 2-channel sources.
Proven performance.
In both Japan and the United States where
4- channel sound is becoming the rule rather
than the exception, QS type matrixing is
standard.
Listen to this remarkable equipment at the
London showroom of Sansui.
It's right next to the GPO
tower. Our technical experts
0 Li Li
are ready and willing to give
advice on specifications and
Or send in this coupon
rl
full information.
fprices.
or
.
Excellent separation.
Both encoding and decoding matrices are
symmetrical. Together with the new QS VarioMatrix in the decoder, an inter- channel separation of 20dB or more is no problem.
Maintains present hi -fi standards.
High standards are maintained. Because of
a unique phase shift technique, the quality as
well as the quantity of input information is
To: Sansui London Showroom,
39/41 Maple Street. London W1P 5FU Telephone
Please forward all technical 4nd price details on the
ne\w QS 4- channel encoder and decoder.
:
01 -580
5353
My name
N1
address..
Postal code
Sansui
Sansui equipment is distributed in the United Kingdom
by Veruitrou Ltd., Thornhill, Southampton.
Vernitron Ltd., Thornhill Southampton S09 QF England
Sansui Audio Europe S.A., Diacem Building, Vcstingstraat 53/55 - 2000 Antwerp Belgium
Sansui Electronics Corporation 55 -11 Queens Boulevard, Woodside, N.Y. 11377, U.S.A.
Sansui Electric CO., Ltd. 14 -1, 2- choute, lzumi, Suginamiku, Tokyo 168, Japan
93
ALLEN AND HEATH SIXTEEN BY EIGHT
CONSOLE
Angus McKenzie /Tony Faulkner
MANUFACTURER'S SPECIFICATION
Mic Input
Impedance: greater than 200 ohms balanced.
Sensitivity: -80 dB.
Attenuation: 20 dB switchable.
Gain control: 40 dB continuously variable.
Equivalent input noise: -126 dBm.
Line Input
Impedance: 25k ohms unbalanced.
Sensitivity: -6 dBm.
Maximum level: +14
-
dBm.
Line Output
Impedance: down to 600 ohms unbalanced.
Nominal level: 0 dBm.
Maximum level: +18 dBm.
Overall
Signal to noise ratio: -75
talk:
Cross
better than
dB.
-60 dB.
Intermodulation distortion: 0.3"; overall.
Frequency response: 30 to 20k Hz ±1 dB.
Output level from console: 0 dBm.
Equalisation
Treble: +16 dB at 10 kHz.
Middle: +14 dB on a parametric frequency centre between
Bass:
1.8 and 7.5 kHz
_i16 dB at 100 Hz.
General
Power requirements: 24V dc from
Weight: 104 kg (as shipped).
Dimensions (I x w x h): 150 x 87
an external power supply.
x 23
mm.
Manufacturer: Allen and Heath Ltd, Pembroke House,
Campsbourne Road, Hornsey, London N8. Phone: 01- 3403291.
Telex: Batiste LDN 267727.
Price: £1800.
US agents: Audio Techniques Inc,
142
Hamilton Avenue, Stamford,
Conn 06902, USA. Phone: (203) 359 2312.
Price: $6795. This includes an extended Switchcraft patch bay (not
fitted to UK models) and power supply. Extras include 48V phantom
powering (12V standard) at $250 and meter illumination for an extra
$100.
ASSESSING THE performance of a studio mixing console poses several
problems for a reviewer, not the least being exactly where to start
with so many functions to check through. The Allen & Heath posed
a further problem, because its very modest UK price tag of £1800
for a 16 input, eight output desk implies that various compromises
will have had to be made in order to keep the cost so low. All
the same, whatever the price- bracket, any mixer should meet up to
basic requirements which will either deem it fit or unfit for the job.
FIG.
1
-------.==_=
----==:::-----------------::
=
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-----=-..
--am:
a=
==_=:::_
ALLEN + HEATH EQ CHARACTERIST CS
MAX /MIN
100Hz,MAX/MIN 10KHz
==_==
_:::__
._8=E=:EE_===-----____...
__NN...._
_____:::_._
_::.______::::__
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___________-____.
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_IN_
______._
c'___NN_u.NNNNNN
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..NNNNNN__NN_..._
____._______ __._NN_o._
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___:::_=____.::____._..._
____
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___
31.5mm /s
PAPER SPEED.
10mm /s
20
50
_
_NN.:ii_.
100
__
___
200
500
000
FREQUENCY IN Hz
94
i
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____..___.. _NN._NN_...
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ZERO LEVEL
-10dBV
_.
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__
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Wr. SPEED:
FIG. 2
_
STUDIO SOUND, OCTOBER
1975
2K
5K
=
Cl==::::
RMS
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LOWER LIM
FRED.: 20Hz
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..______..._`___..
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_...
__MINN_...______...
C=__.::
__NN_::: __NN=:
31.5mm /s
PAPER SPEED:
__ _
10mm /s
-10dtV
MAX /MIN10KMIDSCALE 87.5KHz
__
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ií
ü:
I::____-_
___.._
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ZERO LEVEL
10K
=.
=_:EE9
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RECTIFIER:
-
=__:: _
-------.
==_=::: -----..._
--------_
---------
ALLEN + HEATH 16/8 EQ CHARACTERISTICS
=a=:55E
:_
====lëE:
RECTIFIER: RMS
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The mixer is attractively packaged and laid out in much the same
way as most studio consoles. It is 1.6m wide and just under lm
deep. All 16 input channels are on the left, and the eight main
output groups on the right. The monitor mixdown controls are
incorporated in the output group modules. To the right of the
output groups is an area suitable for the engineer or producer to
put session paperwork, and at the back of this area is the jackfield.
The construction of the desk is modular, and each module
includes the relevant input /output XLR and jack sockets.
Microphone inputs are balanced XLR sockets; line inputs,
tape- returns, cue output, echo-send outputs are all 6.25 mm
Type A jacks unbalanced and group outputs are male XLRs although
they are not balanced.
To begin, we measured the input impedance of the input module.
The line input showed a variable figure, depending upon equalizer
settings. The line input is by no means sophisticated in design
it looks straight into the mic line switch which then feeds the
equalizer via a passive breakpoint (ie no gain control or attenuator
available). Three channels were checked, and they agreed at 29 kfI
with the tone-controls flat and at a minimum figure of 10 kit
with a lot of mid-boost--all readings being at 1592 Hz.
This is clearly not a very satisfactory state of affairs- findings
(later) concerning the overload performance suggest that the line
input would definitely benefit from some change in concept and
design.
The input impedance of the microphone amplifier was also
inconsistent with different settings -not the equalizer this time,
but the input attenuator pad. With the pad switched in by means
of one of the pushbuttons on the module, the impedance presented
to a microphone is 1.7 kO
figure for which there is no criticism.
On the other hand, with the pad switched out, the impedance falls
drastically to below 400 ohms which is not satisfactory for many
microphones and could produce bass loss. The microphone
input also usefully applies a phantom voltage (23V) for condenser
microphones such as C451, Calrec CM 21.50, which can regulate
the voltage to suit their requirement. This voltage, however, would
not be suitable for 48V types (U87 etc). Although phantom- powering
should have no adverse effect on dynamic mics, our experience
has not always borne this out. On one occasion, the output of one
of our AKG D202 dynamic microphones degraded to loud
"frying eggs" noises, and this was isolated as the presence of
phantom- powering. We turned off the voltage, and the microphone
was restored to normal -we would therefore suggest that the
Allen & Heath mixer include a phantom on /off switch to allow
for this.
We next checked the sensitivities of the microphone and line
inputs. With the channel fader set to maximum, the group fader
at maximum, and the routing to one output group only (by turning
the pan -pot hard in one direction) the voltage gain from the
microphone input to line input was 105.5 dB. Such a high gain is
rather excessive. The gain control for the microphone input has
an alarming characteristic at the end of its travel, where the gain
suddenly leaps at you. This characteristic is mentioned clearly in
the instructions, but it is still quite art operational surprise. Below,
we tabulate the input voltages required to produce an indicated
20
50
___::
_____:..
:ii___NN_..._____:-..
C==::::
--100
200
500
000
FREUUENCY IN Hz
2K
5K
10K
FIG. 3: Intermodulation
performance. Output level 0 vu
(0 dBm). Mic input level -40 dBm
with fader at -6 dB. Measurement by
SMPTE method. 7 kHz centre frequency.
output of 0 vu indicated with group and channel fader set at
maximum.
Mie:
Line:
No pad. Control
Pad. max
Pad. min
at min
-54.25 dBV
-29.75 dBV
-79.75 dBV
-16.5 dBV in all positions of attenuator and sensitivity
No pad. Control
at max
-107.75 dBV
axis 50 Hz /div y
axis 10 dB/div. FIG. 4:
X
Spectral display of alignment
oscillator output, y axis fsd =0 dBm,
10 dB /div x axis fsd =10 kHz, 1 kHz /div.
problem. With the tone controls set flat, the response is flat enough
for any typical application and deviations from the specification of
I dB 30 Hz-20 kHz can be put down to the tone controls not
being precisely centred. Perhaps an eq out switch would be of
advantage but it's accepted that you cannot expect an £1800
mixer to have everything one finds on a £20000 one. The equalizer
has three ranges:
10 kHz (treble). This gives a variability of +18 dB at 10 kHz.
The curve is still rising at 20 kHz and we would prefer a
shelving characteristic. At maximum treble, the 3 dB point
of the network is 2 kHz.
2.
Mid. This function has two controls, one controlling the
frequency continuously across a considerable proportion of the
mid-band, the other controlling the amount of boost or cut.
The graph shows the maximum boost and cut available at three
typical settings of frequency (counter clockwise, halfway and
clockwise). The actual centre frequencies deviate rather
from those printed on the module itself (indicated 7.5 kHz
turns out to be 10 kHz). The Q of the circuit also alters quite
a lot with frequency, but the facility of having a continuously
variable centre frequency is useful. The available variation drops
with higher centre frequencies, but is still +15 dB which is
more than adequate.
100 Hz (bass). A variation +18.5 dB, 16 dB at 100 Hz is
3.
available with this control. The boost is a broad peak around
60 Hz with the 3dB point at 800 Hz. The cut is a basic roll -off
all the way down to the bottom of the response curve.
We suspect that the lack of control in between bass and the
lowest mid frequency adjustment at 2.5 kHz could be felt on certain
occasions -but the continuously variable mid frequency is an
attractive feature. The input module also includes a hi -pass filter
which operates on the microphone input only, and although it has
some effect, we feel it should be steeper. When the mie input was
driven from a 200 ohm source, insertion of the bass roll -off made
only 1.5 dB difference at 100 Hz, 3 dB at 50 Hz and 6 dB at 25 Hz.
Now on to the routing. The desk has eight main output groups,
one cue (foldback), two echo groups and a solo (pfl) group.
Routing to the main output group busses is by means of four
push- button switches and a pan -pot. With the top button
depressed, the pan -pot directs the output of the channel between
groups one and two. The other three buttons route the output of
the pan -pot to groups three and four, five and six, or seven and
eight
any combination thereof. So that if, for example, you
want to feed the input to groups one, two, five and six in equal
proportions at the same time, all you have to do is to punch the
1.
Even at its very lowest, the microphone gain is still rather high,
and this is reflected in the overload margins, which we investigated
next and are shown below:
Mic:
Line
No pad. Con
No pad. Con
at max
at min
-24.25 dBV
-83.25 dBV
With equalizers set flat +13 dBV
With maximum mid -lift -5.25 dBV
(All figures refer to
Pad. Con
at max
-56.25 dBV
Pad. Con
at min
+0.75 dBV
kHz clip, with channel and group faders
output /mixer amp overload.)
We do not feel that the overload capability is sufficient on
microphone input. The mixer is clearly aimed at the pop music
business and should make allowance for the high signal levels often
encountered in this application. The margin could be improved by
sacrificing some of the rather high gain, in favour of some more
feedback around the microphone preamplifier.
its present
The line input overload regrettably speaks for itself
form, the line input cannot be attenuated on the mixer at all
before it reaches the equalizer. It is evident that trouble can arise
on mixdown as soon as the equalizer section is touched. A fully
modulated master tape will often peak 4 to 6 dB (or more) above
a flux -level of 320 nW /m, which on a typical studio recorder
represents a voltage of the order of + 12 dBV, already sailing too
close to the wind before applying any eq. Even if one's standard
operating level is dropped 4 dB (ie Dolby level 0 dBm) the
amount of eq added before clipping onset is very limited and below
the capability of the comprehensive tone controls.
The noise performance of the microphone input was exemplary,
at 126.5 dBV (ie 128.75 dBm) equivalent self- noise. This figure
refers to 200 ohms and is limited to a bandwidth 20 Hz-20 kHz,
being taken on a fast IEC rms characteristic meter -with the
mixer set for an overall gain of 80 dB. The noise performance of the
entire console was most satisfactory, as was the absence of hum
and radio breakthrough.
Our next task was to investigate the equalizer section of the input
module -the graphs tell most of the story, and there is no particular
1
set to avoid line
-in
-or
96
95
IN
ALLEN & HEATH 16/8
buttons for groups one /two and groups five/six and put the pan -pot
at centre travel. The law of the pan -pot is rather poor, in that a very
small rotation of the control whisks the sound from hard -left to
just off centre. The pan -pot has optimal loss of around 4 dB at
the centre of its travel, as compared to the extreme left or right
position. With the pot hard in one direction, the crosstalk on the
opposite channel at 1 kHz was 71 dB, which is well within
the specification. The breakthrough on mie of a line input was
also very good at over 100 dB. Cue send is pre-fade, and the
echo sends are both post -fade.
The auxiliary module is located physically in between the input
and output modules. It includes sockets for the external power -supply
(a very good Advance one was supplied with the mixer) in the form
of a miniature three pin Bulgin, and 6.25 mm jacks for the monitor,
cue, echo and talkback outputs, and also for echo and stereo tape
return. The controls for the cue and echo output groups are in this
module, the performance of which is detailed later with the
distortion figures of the main output groups. An oscillator is built
in which has two controls -one for frequency and the other for
level. This oscillator falls short on account of the level of harmonic
distortion. The picture of the harmonic content of a 1 kHz
fundamental at 0.775V output tells the tale well- showing the
second and third harmonics alone to be 1% or worse. Using the
tone to check out a system would be most inconclusive since it
sounds so rough to start with. The frequency is continuously variable
from 805 Hz to 8.8 kHz, and the level can be varied from 68 dBV
to +13.5 dBV-the output appears on the jackfield, and the
oscillator can be turned off to avoid any possible breakthrough.
The next function of the auxiliary module is that of monitor
selection. There is a variety of options available, and most
requirements can be catered for. Monitor can be from stereo group
out, stereo tape- return, the output of monitor mixdown as
selected on the 16/2 monitoring mixer in the output modules
(including sync with various switching), the cue output (which can
also be either or both the input or output cue mix, by means of a
potentiometer whose slider goes to earth), the solo (pfl) output, a
mono mix, or whatever is routed on the output modules to the cut
position. This system is clearly comprehensive enough for most
applications, and also includes the possibility of `wet' monitoring.
There are two functions remaining on the auxiliary module.
The first is the stereo echo-return routing and level, and the second
is the talkback section. The mixer has a microphone built -in
which one can route to studio talkback, cue or slate (talk-to- tape).
The quality is adequate and intelligible, although hardly high -fidelity
also picks up a certain amount of bonking, if any part of the
-it
COMPUTER MIXING
cutting direct from the master tape through the
computer- assisted mixing console without the
need for a two or four track master tape and
thus without the quality reduction inherent in
another tape generation.
In addition to the requirement for some
memory assistance in the music recording
mixdown room, multitrack recording techniques are becoming increasingly popular in
television. It has long been the wish of many
television producers and directors to have the
same flexibility of post-production facilities as
is enjoyed by the film industry. This is mainly
the ability to edit film simply, being capable of
seeing exactly what is happening while the
edits are being made, and also having the
facility for post-production dubbing of music,
dialogue and effects. Recent progress in the
technology of electronic video tape editing and
the introduction of multitrack recording
techniques into television centres is leading the
way towards this end. In recent years, there
has been a considerable increase in the amount
96
STUDIO SOUND, OCTOBER 1975
desk is knocked while it is being spoken into, but is adequate.
Meter monitoring is achieved by eight large vu meters, which
read line in /out etc by means of the basic monitor switching. We
were disappointed by the meter ballistics, which are rather slow to
respond. The Bell specification for a vu meter states that it should
reach 99 on the per -cent voltage scale in 300 ms (ie 0.1 dB). These
vus underread 1.5 dB on 256 ms burst of kHz, 4 dB for a 128 ms
burst, and 7 dB for a 64 ms burst. This is not very good, and
would encourage an engineer to drive the system too hard
particularly on material which can be difficult for even a good vu
meter to present adequately, such as muted brass, or speech.
However, this problem could be put right we feel sure, for clients
who require more accurate meters and are prepared to pay the
extra, since good meter movements do come expensive.
Output modules include a male XLR socket for the group output,
and two mono jacks for multitrack tape return into the monitor
mixdown facility. Two monitor returns are included on each module
to facilitate monitor mixdown (with sync) of a 16 track recorder.
Various combinations of line in /out and sync can also be routed
to the cue output.
A reading of 0 vu corresponds nominally to 0.775V although the
meters underread marginally by between 0.25 dB and 0.5 dB.
Although many studios use 0 vu to represent a voltage level of 1.23V
(ie +4 dBm =O vu), the choice of 0.775V is reasonable bearing in
mind the operating levels of possible associated equipment (such as
Teac 3340 four track recorders) and also helps the overload margin.
With controls set to avoid clipping the input stages, we checked
the maximum output of each of the group amplifiers. The average
figure attained was +15.8 dBV ( -; -18 dBm) at kHz. The same
measurement was repeated for the other output groups, and the
results are as follows:
1
-
1
Output clipping into open circuit (ie > 100 kt»
Main Group
Echo
Cue Monitor
15.8
12.5
15
-10.7
(all dBV
at
1
kHz)
The figures when the output was loaded with 600 ohms were not
significantly degraded, and this was confirmed when the output
impedances were checked at 1592 Hz, the results of which are
shown below.
Main Group
70 +47.5 pF
Echo
2.250 +73 pF
Cue
200
Monitor
40 +50µF
These impedances are very low and mean that there is very
unlikely to be any difficulty associated with loading the mixer, or
with losses incurred with the use of long cables connected to the
outputs, a good design feature.
98 0-
of post -production dubbing and rerecording
undertaken in tv centres. As the video tape
editing process requires the utilisation of a
recorded time code (normally the SMPTE), the
integrating of a computer-assisted mixing
console is an obvious development.
Number of controls
This article would be incomplete without
some reference to the number of controls on a
sound mixing console, which should be put
under the control of a computer or memory.
There seems at this moment to be a tendency to
put every function on the sound mixing console
into this category. As I have emphasised, it is
my belief that the one problem requiring most
attention in giving electronic aid to the sound
balance engineer is the ability to update the
settings of the sound mixing console after they
have been memorised. The solution proposed
using motor- driven controls would be unduly
expensive and pose considerable space problems, if every control on a mixing console is
memorised. I believe it is a far better solution
to provide a first -class man -machine interface
on the main controls of a console (ie all the
channel and group faders together with master
echo send and return controls) than to attempt
electronic memory assistance for every control
and then to fail to provide good instantaneous
up- dating facilities.
Finally, it is important to point out that in
any discussion of memory techniques and
sound mixing consoles, it is possible to lose
sight of the prime requirement, which is to
provide the highest possible quality of sound
for the finished product. The advantage of
harnessing a computer with its flexibility and
large memory and the use of simple updatable
controls on the mixer provide the balance
engineer with the tools to achieve this result.
Summary
Memory assisted mixing has developed
along the lines of recorded data on tracks of
the tape recorder and using voltage controlled
amplifiers for level control. A computer can
provide more versatility and the use of electromechanical controls eliminates severe problems
of operator update of control settings.
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97
ALLEN & HEATH 16,4
main group outputs at I % for +6 dBV out (2V).
Finally, the desk was tried out in practice. Most of our findings
on the test -bench were confirmed-the very low hum and
noise was most apparent, as was the flexibility of the monitoring.
The distortion inherent in the monitoring section was audible, as
was the apparent necessity to run the output group faders near
maximum. Although it is reasonable to work with them flat out
when laying individual tracks down, it is often useful to raise or
lower the gain of a stereo mix without having to juggle with 16
faders. Operating the output group faders below 10 dB courted
clipping, and it might be an alternative for the gain to be reduced
before the output fader and increased after it. The law characteristics
of both the microphone preamplifier gain and pan -pot as discussed
previously were not altogether satisfactory in operation.
We hope that the reader will appreciate that we have not made
much allowance for the price of this mixer. Compromises have
inevitably had to be made, such as Ruwido faders rather than the
more sophisticated and much more expensive longer -travel
conductive plastic types. At £1800 in the UK the mixer offers
attractive value for money if you cannot afford to purchase a fully
fledged studio mixer at a very much greater price. However, the mixer
is not without problems, some of which could be relatively easily put
right and some of which seem to indicate rethinking. The line input
arrangement definitely needs looking at, as do the positions of the
breakpoints in the mixer logic. The channel breakpoint is before
the equalizer, immediately after the mie line switch, which is not
really the most useful place, and the output break is after the group
amplifier immediately before the output socket.
Before embarking on the final section of our tests, actually trying
the desk out, we carried out some checks on harmonic distortion
at typical operating levels. The main output groups, when fed
through line input, were very clean at 0 vu out with second and
third harmonics of below 0.02% (k2 74 dB; k3 = -78 dB). The
echo groups were not quite as good at 0.05% second, and a good
figure of 0.004% third harmonic of kHz. The cue output had
a second harmonic of 0.16% ( -56 dB) which could be better
particularly when you see how clean the main groups are. Finally,
the monitor output, using the monitor mixdown function had
distortion clearly audible at 0.775V out, and measured as 0.32%
second harmonic, and 0.05% third. Thus, monitor and cue output
amplifiers would certainly benefit from some attention but the
most important ones, the main output groups, were most
satisfactory.
We checked im distortion throughout the chain, feeding a 4:1
mix of 50 Hz +7 kHz to SMPTE requirements into the line input
at a level of 0.775V, with the main group fader set at
dB and the
channel fader set to give an indication of 0 vu -this gave a
satisfactory reading of 0.12 %. At an output of =5 dB ref 0 vu the
im rose to 0.19%, and at +10 dB to 0.37%. Similar results were
obtained when the test signal was applied at a level of 40 dBV
into the mie input, and the photograph indicates the result.
The im distortion in the monitoring circuit was worse than the
1
6
LETTERS
on January 21, 1901, was entitled Puzzle Plate
and bore three tracks on its single side
a
monologue, a piano solo and a song with piano
accompaniment. The accuracy of the grooving
is as good as any Emile Berliner record of that
period.
All of these were fixed -pitch jobs -but if the
duration of each of the Monty Python tracks
was only eight minutes and the disc size 12
inches at 33) rpm
.
...
bigger problem than actually existed.
The paragraph concerning the horse race
recording contains an error: The American
Victor (25889) release actually states 'recorded
in Europe' on the label and is pressed from an
HMV matrix. The title was Pick the Winner
a horse race game for parties, composer( ?)
credit being given to one Fowler. The record
also appeared here on the parent label.
The Columbia subsidiary label Harmony
produced a short-lived series (6000H) on which
each side contained two versions (one orchestral, one vocal) of a popular song, the two
performances being distinguished at opposite
sides of the perimeter by the letters A and B.
First honours must, I think, be accorded to
England for the first record of this kind. An
Emile Berliner seven -incher recorded in London
-
REVOX A700
noise, and if it is not, clearly the replay is
should be changed.
As with the 77 series the heads are non -ferrite
and seem to wear rather fast. This wear is
greatly accelerated if rewinding is done
frequently with the rewind button held down
to allow recordings to be monitored. Although
the tape is held against the head a mute brings
the level down very considerably -in fact too
much I think; allowing rewind without holding
the button down mutes the head completely.
Occasionally the mumetal screen in front of
the head stuck, thus holding the tape permanently against the head. This has to be watched,
since it will quickly cause head wear. All the
machining of parts has been very accurately
done; changing head blocks is simple, no reazimuthing being necessary. I thought that
98
STUDIO SOUND, OCTOBER 1975
.
.
Yours faithfuls, John Davies,
Cottage, Burnham, Bucks, UK.
1
Walnut Tree
Dear Sir, Following my call to you this morning
about the Pyral story you were good enough
to publish on p. 16 of your August issue, I
would point out that part of its phraseology
inadvertently suggests that Pyral manufacture
computer tape in their new Eastbourne factory.
some parts of the body work were rather
flimsy, in particular the feet and some of the
plastic work which can easily be broken.
Although the recorder was designed to work
vertically it performs equally well horizontally,
although in this position access to the input
and output sockets on the panel under the
bodywork is awkward.
I agree absolutely with Hugh Ford's strong
recommendation for this machine; although it
may seem at first to be rather expensive, for
the facilities offered it is very realistically
priced. What other machine is available which
can take NAB spools, has three speeds and
interchangeable head blocks, is provided with
consistent forward and back tension, flutter
roller, excellent overall response and very low
wow and flutter at anywhere in this price
bracket? My own experience is that the
machine can work very hard and reliably for
long periods, although it docs require care in
This is not the case; such tape comes from the
parent company in France. As there are
matters of inter -company agreements involved
and your paragraph might appear to suggest
they are being contravened, it is requested that
an amending paragraph be published in STUDIO
SOUND as quickly as possible to correct any
possible misunderstanding among readers.
It is further pointed out that since issuing
the original editorial on behalf of my clients,
the UK manufacturing section of Pyral now
trades under the name of Pyral Magnetics Ltd,
and Pyral (UK) Ltd continue as distributors of
other Pyral products manufactured in France.
These of course include computer tapes.
Yours faithfully, Alfred Marks, Associate
Director, Arthur Mattless- Williams Ltd, Unit
14, Airport House, Purley Way, Croydon CR9
4LB, UK.
The offending note seems at worst ambiguous.
Still, anything for a quiet life
... -Ed
It is obviously not so robust as its much
more expensive rivals, but it out-performs its
junior rival, the series 77. It would be possible
to provide break points in both record and
replay circuitry to insert noise reduction units,
although quite a lot of electrical and mechanical
work would have to be done to wire up the
relevant sockets and switching. I particularly
recommend the 700 for use in dubbing suites,
quality checking rooms, and by music production companies who often have to play back
tapes of all types and speeds in a hurry, but to
a high standard. Already several studios have
bought these machines and are well satisfied.
All the pre -sets are easily reached by taking
off the back cover, and it should be simple for
a skilled engineer to set up the recorder to any
required tape type. It is undoubtedly a machine
that is going to be seen around for many years
to come, not just in this country, but all over
the world.
use.
Baffled by Hi-fi?
If so, then the book for you is
HI -Fl IN THE HOME, in which all
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assumptions are made about the
reader, except that he likes music
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this best -selling and very
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Signal to noise ratio: input terminated with 47K resistor. All filters
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Frequency response: All filters at
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Filter slope: Better than ± 13 dB
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Filter ranges:
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Trade enquiries welcomed.
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To: E.S.E. Electronics, 2 Upper
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99
Classified Advertisements
Advertisements for this section must be pre -paid. The rate is 12p per word, minimum £1.20. Box Nos. 25p
extra. Semi -display rates on application. Copy and remittance for advertisements in NOVEMBER 1975
Issue must reach these offices by 16th SEPTEMBER 1975 addressed to: The Advertisement Manager,
Studio Sound, Link House, Dingwall Avenue, Croydon CR9 2TA.
NOTE: Advertisement copy must be clearly printed in block capitals or typewritten.
Replies to Box Nos. should be addressed to the Advertisement Manager, Studio Sound, Link House, Dingwall
Avenue, Croydon CR9 2TA, and the Box No. quoted on the outside of the envelope. The district after Box
No. indicates its locality.
STUDIO FACILITIES
(Continued)
*For hire Revox
A77 (HS+LS, NAB+CCIR,
Vari- Pitch, Vari -Speed etc), AKG, BX20
Quad 303, Revox A78, Spendor speakers,
Teac four channel, mic stands, etc. Radio
Recordings 01 -586 0064.
RECORDS MADE TO ORDER
STUDIO FACILITIES
Roger
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Telephone Bracknell 54935.
D
London Road, Binfield, Bracknell, E
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Tape to disc. 12in. L,P.
£3.60.7in. 45 rpm £1.50. E.P. £1.65. Pressings
stereo /mono.
Tape Copying, 14 Willows
Avenue, Morden, Surrey. 01 -648 9952.
CASSETTE COPYING SERVICE
Cassettes made from your master tapes. Also
Recording Studio facilities and open reel
duplication.
64
*Sound News Productions. Britain's oldest
full-time tape /disc/cassette transfer service.
Direct transfers, pressings for private and for the
Fund -raising advisory service for
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Societies, Choirs, Bands. Ferrograph, Grundig,
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18 Blenheim Road, London W.4. Tel. 995 1149.
PRESSINGS
1
specialist recording studios for sound commercials and
radio programmes: contact Tony Newman orJayne.
55 Charlbert St, London, NW8 6JN. Tel. 01 -722 8111.
0 COUNTY RECORDING SERVICE H
mono masters and lacquer á
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Single discs, -20, Mono or Stereo, delivery 4 days
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PRESSED IN VINYLITE IN OUR OWN PLANT.
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PO Box 3, Hawk Street. Carnforth, Lancs.
Tel. 2273
*For Sound
Communication use our open reel
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(Publishers) Ltd., Field House, Wellington
Road, Dewsbury, West Yorkshire WF13 1HF.
Tel. 0924 469436.
MICROPHONE PREAMPLIFIER
Small pc board (70 x 90mm) accepting two 30 -600 ohm
microphones (balanced inputs) and feeding loads down to
5K ohm. Board plugs into 12 -way gold edge connector
(supplied) and has presets for gain. Professional specifications. Supply +24v but will adapt for 10 to 40 volts.
Board built and tested, 2 channels E37. Kit 429.
PEAK PROGRAM METERS TO BS4297
also 200 kHz version for high speed copying:
Drive circuit,
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Complete kit E12. Built and aligned E17.
ERNEST TURNER PPM meters. Below scalings stocked
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Tape - disc pressings,
demo's, masters, any quantity. Studio/mobile
Neumann disc cutter. S.A.E. brochure. 1
Broomfield Close, Rydes Hill, Guildford. Tel.
0483 61684.
RAC MIXERS
Custom -built mixers for groups, P.A.,
hospital broadcasting, recording, discos, etc.
RAC plug -in audio modules for building
your own mixers.
Sony, Akai, TEAC, Tandberg, Marantz, Lux,
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Shure, Calrec, AKG mikes and stands, etc.
APRS Manufacturing members.
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Tel. 0788 -810877 (Rugby)
Coll, write or phone us
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Reliable service.
STUDIO SOUND, OCTOBER
FREQUENCY
SHIFTER
FOR
HOWL
REDUCTION
PUBLIC ADDRESS
SOUND REINFORCEMENT
In any public address system where the microphones and
loudspeakers are in the same vicinity acoustic feedback
(howl-round) occurs if the amplification exceeds a critical
value. By shifting the audio spectrum fed to the speakers
by a few Hertz the tendency to howling at room resonance
frequencies is destroyed and an increase in gain of 6 -8dB
is possible before the onset of feedback.
SHIFTERS IN BOXES with overload LED, shift /bypass
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Jack or XLR audio connectors.
Type
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B
C
Input impedance 200Kohm 200Kohm IOKohm Balanced
Output impedance 2Kohm 20or600ohm 20or600ohm BAL
PRICE
ES8
L68
L84
SHIFTER CIRCUIT BOARDS FOR WW July 1973 article.
Complete kit and board E24 Including p.s.u. and
Board built and aligned
L31
mains transformer
DESIGNER APPROVED
SURREY ELECTRONICS
The Forge, Lucks Green, Cranleigh, Surrey G U6 7BG
(STD 04866) 5997
CASH WITH ORDER less 5% U.K. post free, add V.A.T.
1975
See
CE -COURT ELECTRONICS
for Fast, Professional Service
P.C.B. Assy. Mech. Assy. Cableform Manfg.
Full details of these and other services from:-
Cambridge Trading Estate, Hanwell,
London W7 3PA.
Tel. 01 -567 9672 3
* Revox
A77 sold, services, modified Full.
range of modifications that only we carry out.
Ring 01 -586 0064, Radio Recordings.
W O
L L E N SA K 2 7 70 A V
CASSETTE FAST- COPIER
SCS Appointed Main Dealers
Demonstrations
Personal Service
Maintenance
Cassette Fast-Copying--Short or Long Runs
Full Information on Request
SOUND CASSETTE SERVICE
(SSI)
PO Box 2, Gerrards Cross, Bucks SL9 8EG
Tel: 02813 84409
FOR SALE-TRADE
FOR SALE -PRIVATE
*Used equipment for sale. 2 x Sansui AU999
amps, 1 pair Tannoy corner yorks, Revox A77
H.speed, 3 x Sony amps, QS decoders. All mint
condition. Audio Centre Sheffield, Professional Dept., 284 Glossop Road, Sheffield 10.
*Allen & Heath Mini mixer (6 in, 2 out),
complete with 4 balancing transformers, monitoring box comprising power supply, PPM,
oscillator, AB monitoring for LS and cans,
DIN connectors. Also echo unit and foldback
box with outputs for 6 airs cans. £170 the lot.
Box No. 706.
0742-737893.
*Alice custom-built 6/2 mixer, plus 4 -track
A/B monitoring. Also Teac A3340 recorder.
01 -947 5149.
Viewing by appointment with Malcom
Jackson, The Studios, Rickmansworth,
Herts, England
Tel. Rickmansworth 72351
to order of patchbays, multi cores, panels, outlet boxes and power distribution units, call 01 -891 2815.
12" Gramophone Record Presses
Silvering and Electroforming Equipment
Associated Plant and Accessories
Please reply to:
EQUIPMENT
We are suppliers to many well -known companies,
studios and broadcasting authorities and were established in 1941. Early deliveries. Competitive prices.
Large or small quantities. Let us quote.
E. A. SOWTER LTD.
Transformer Manufacturers and Designers
Dedham Place, Fore Street, Ipswich IP4 IJP
Telephone 0473 52794
Metro Radio are looking for a young man or
woman with knowledge of broadcasting techniques,
and some studio experience to join a team of five
technical operators, responsible for a wide range of
programme output from this established independent
local radio station covering the Tyne and Wear region
GEOFFREY COATES
Immediate delivery.
Write or phone J. J.
Francis (Wood Green) Ltd., Manwood House
Matching Green, Harlow, Essex. Tel Matching
GLENN MILLER
A. J. HIBBERD
Waverley Road, The Kent, Rugby, Warks.
or phone 6473 daytime, 71066 evening
14/.0076 x 2 braided
mic cable in stock. 45ín. spring tensioned mic
arm, }in. thread for stand adaptors, designed for
D202 etc. Heavier springs for Neumann mics.
Radio Recordings 01 -586 0064.
Hermes Development Company Ltd
Handsworth Wood Road, Birmingham
B20 2DS
or phone 021 -523 7307
*Audiofact No. 1 You can build 8 Cathedral
Complimiters into your mixer for less than
the cost of the one medium price competitor
and they perform. We also manufacture a
range of high quality audio modules. S.a.e.
details. Cathedral Sound, Fourways, Morris
Lane, Halsall, Lancs L39 8SX. Tel. Halsall
! !
-
(0704) 840328.
Metro Radio, Newcastle- upon-Tyne, NE99 IBD
Tel. 0632 884121
*For
Studio installation hardware, hardwood
rackfronts, jackstrips, tagblocks and frames,
panels, cable and connectors, call: 01 -891 2815.
FUNDS AVAILABLE
A large public company is seeking an investment in, or acquisition of, an established
Recording Studio in the London area. Must
have good track record, able management
and growth potential.
Details to Box 707.
offers for lot or batches of five. 01 -359 0970.
*Audio Developments mixer, AD 007, with
additional facilities.£875 o.n.o. Tel. 01- 8924180.
476.
Private collector requires recordings taken from BBC
broadcasts during 1944 -45 of THE AMERICAN BAND
OF THE A.E.F. who were stationed in the UK during
this period, I am particularly interested in complete
broadcasts by the full Orchestra and various subunits under the titles of: "Swing Shift ", "Swing
Sextet ", "Uptown Hall ", "Johnny Desmond Sings ",
"Strings With Wings ", "The American Band of the
AEF ", plus any 16" Transcriptions, "Air Checks" and
"V" Discs etc. in any condition, tape copies acceptable
but will pay very good price for original discs or will
exchange from my collection.
Also requires AAF band from "Uncle Sam ", "1
Sustain the Wings" show and AFRS and OWI Transcriptions plus his civilian band broadcasts and GMMS
Transcriptions. All letters answered.
38
Programme Controller
*100 reels +in. audio tape available. Once used,
*Nagra III and IV and SN models available.
GERALD REYNOLDS
TECH. OP.
SOWTER TRANSFORMERS
*Ten different colours of
WANTED
*For pre-wiring
Write giving details of experience to:
59
DISC PRESSING EQUIPMENT
mixer. Tel. 01 -722 3720 after 6 p.m. weekdays.
CONTENTS OF 16 TRACK STUDIO
Including: Tape recorders, Mixing consoles, Microphones, Reverberation devices, Dolbys, Compressor /Limiters,
Delay units, Grand piano, Microphone
stands, etc.
7
(Continued)
*Dolby A360s, Uher 4400L, Chilton Mk 3 10/2
SALE
FOR SOUND RECORDING AND REPRODUCING
WANTED
*New microphone cable, twisted twin with
braided screen, Cannon XLR each end, 75ft.
long. £7 each including p/p and V.A.T. C.w.o.
Hamilton Mobile Sound, 32 East Walk, East
Barnet, Herts.
*4 -track half inch branch Appleby heads
ERP8 unused. £40 each. Also 2 -track Bosen
£18.50. Also jack fields, all ex-stock. Harris, 4
Collegiate Crescent, Sheffield S10 2BA. Phone
*All Nagra equipment urgently required for
cash. J. J. Francis (W.G.) Ltd., Manwood
House, Matching Green, Harlow, Essex CM17
ORS Tel. Matching 476.
SITUATIONS VACANT
664784.
*Ferrograph Series Seven full track mono in
metal case, hardly used £200 o.n.o. Tel.
Slough 45403.
*Immaculate Revox A77 type HI128 with
power amps. sel -sync, vari -speed and ilium
remote control list price £560 + VAT. Purchased, serviced by Revox. London. Offers
around £360. Please to Cown McCubbin
01 -582 0032 or 01 -385 6987
WANTED
*Small Professional studio, just opening, needs
any equipment, mikes, stands, Revoxes, h.
phones, etc. Epsom 24870.
TWEED
AUDIO
urgently require a young enthusiastic Sales
Engineer with technical experience and
ability to negotiate contracts in U.K. and
abroad. Applications should be sent to:
K.
Mustafa,
TWEED AUDIO
Rosewood Industrial Estate, KELSO,
Roxburghshire, Scotland
101
---- ----- - --
----- --
r----
I
CLASSIFIED ADVERTISEMENTS ORDER FORM
I
I
Please use this coupon for your private sales and wants. Rates 12p per word. Minimum L 80. Box Nos. 25p extra.
To: Studio Sound, Classified Advertisements Dept., Link House, Dingwall Avenue, Croydon CR9 2TA. Please
publish the advertisement indicated below for
insertion /s under the heading
I
I
Name
Cheque /P.O. enclosed
Is a
Address
£
Box No. required Yes /No.
If no, please include
remittance to cover name and address and /or Tel. No.
Please
write
in
block capitals.
Link House Publications Ltd., Registered in England No. 96948. Registered Office: 10/12 South Crescent, Store Street, London WCIE 7BG.
INDEX TO ADVERTISERS
A
Acoustic Research (Teledyne)
Acoustic Research (Teac) .
Acoustical Manufacturing..
Acoustico ..
A.K.G.
Alice (Stancoil) Ltd.
Allen & Heath
..
Allotrope Ltd.
..
Apollo Elec.
Amek
Audio & Design Recording
Audio Designs
Audio Developments
Andio Education ..
Audio Techniques
Audix
Automated Processes
A.V. Distributors
.
..
..
..
G
13
26
21
24
18, 19
..
..
..
..
..
..
..
..
..
..
..
..
.
.
B
Bauch, F. W. O., Ltd.
Blandford Press ..
43
41
84
51
81
23
27
20
51
31
65
59
C
2
73
39
16
16
E
Edric Films Ltd.
20
E.M.T. Franz Vertriebsgeliseschaft
E.M.S.
ERC Malcolm Hill Assoc.
E.S.E. Electronics ..
Exposure Hi -Fi
..
8
20
53
99
34
F
Ferrograph Co. Ltd.
Future Film Developments
..
..
.
.
.
.
..
..
R
12
99
46
32
Radio Recordings ..
Raindirk
..
..
..
Revox
R.E.W. Audio Visual Ltd.
Rose Morris
..
Rosser Electronics ..
Rugby Automation Consultants
16
20, 73
104
.
.6,97
..
..
29
85
.
.
10
.
.
.
.
71
.
59
.
14
.
I
..
Icelectrics Ltd.
Ind. Tape Applications
11
..4,5
46
45
99
Cadac (London) Ltd.
Calrec
Cambridge Records
Ce-Court Electronics
Chymes Audio
..
Grampian Reproducers Ltd.
Griffiths Hansen ..
H
Hayden Lab Ltd. .
Hampstead High -Fidelity ..
Helios Electronics
S
Sansui
Scenic Sound Equipment
Schlumberger
Sescom Inc.
.
Shure Electronics
Sonifex
Soundcraft Elec.
Spectra Sonics
Sphere Electronics ..
Surrey Electronics
93
.
J.B.L.
..
K
Keith Monks Audio
Klark Teknik Inc.
L
Lamb Laboratories
Lee Engineering
..
Lennard Developments
Lexicon
..
.
7
.
..
..
..
..
17
89
75
97
12
54
M
Macinnes Labs Ltd.
Magnegraph
Magnetic Tapes Ltd.
Martin Audio
M.C.I.
..
Mercury Elec.
Midas Amplifications
Mustang Communication
N
Neve, Rupert, & Co. Ltd...
P
Partridge Electronics
Penny & Giles
Peavey Elec.
Pyral Magnet ics
.
.
.
.
.
.
6
12
24
87
77
15
49
8
57
ll
39
22
Published by the Proprietors, Link House Publications Limited,
81
8
10 -12
.
17
51
14
61
.
39
34
T
Tandberg ..
Tannoy
Taylor Hutchinson Ltd.
25
27
14
47
79
Trad
Trident Audio Dev. Ltd. ..
Turner Electronic Industries
Tweed Audio
.
.
V
Vitavox Ltd.
46
35
..
16
W
Waters Manufacturing
Westlake Audio ..
50
67, 68, 69, 70
33
Q
Quad
9
103
12
Z
Zero 88
..
Zoot -Horn ..
..
..
8
33
South Crescent, Store Street, London, WCI, and printed by Arthurs Press' Limited, Woodchester,
Stroud, Glos. GL5 5PB.
i
Europe's most modern studios
choose the UPS. 4000
!
TV Studio R.T. Sarajevo, Yugoslavia
They select it because the UPS 4000 console
offers the latest state -of- the -art mixing
techniques for sound recording, broadcast and
television studios. They select it because it
reflects years of Schlumberger experience in the
design and manufacture of professional audio
equipment including tape recorders,
switching networks and special interconnection
units for total studio systems, as well as mixers.
-
This latest console, with fully modular plug -in
units made from die -cast aluminium to ensure
highest accuracies, gives you a system
custom -built to your own requirements but
costs no more than a standard production
model. And modularity means you get the
exact facilities you need now, with the
flexibility for expansion you might need later.
state -of- the -art. With filters, reverberation,
foldback and much, much more.
Studio complexes in countries across Europe
now use the UPS.4OOO. Find out from
Schlumberger about this new concept in
modular mixers. Write for our brochure, now.
rranrrn+++++i
..,-
L1t1111 "'. '.111111111111L
-
Integrated circuits, field- effect transistors,
printed circuit cabling the UPS 4000 is really
-
Schlumberger
SCHLUMBERGER, 296 AVENUE NAPOLEON BONAPARTE, 92503, RUEIL -MALMAISON, FRANCE.
TEL. 977 92 23. TELEX LABOPHY 26 649.
HOW t0
keep the
musical
excellence
you've
already
paid for:
Your tape system
The tape equipment of' your system
is your musical memory bank. It is
the one area where only the best
makes sense. Choose carefully,
select a recording instrument that
neither adds nor detracts from the
sound you put into it. Few
machines really meet this
requirement. The Revox A77 does and by a safe margin.
Your tape recorder and your money
A truly professional quality
tape
unit is your wisest audio
investment. It will last for years
and years.
Witness the number of Revox
machines built more than 20 years
ago that are still in service !It's
hardly surprising then, that Revox
recorders command very high
prices second or third hand - if you
can find them available
Revox owners seldom change other than to a later model Revox.
It's also interesting to note that
our warranty records show that on
average our users have bought 2 or 3
other makes before choosing
Revox. Then we read the lament "I
only wish I'd bought a Revox
sooner."
!
When you play it later, will it still sound the
same?
At first sight this could seem an
unnecessary question. It's not
though. In the course of time a high
fidelity enthusiast upgrades one or
more units in his system.
With time, rising affluence plus
advancing technical innovation in
all aspects of audio, will bring
better reproduction within the
scope of all.
The recordings that you make
now could, therefore, sound even
better in the future - when, as
finances permit, you add a better
amplifier or loudspeaker to your
equipment.
Conversely, a poor recording
made now will sound really inferior
when exposed to more exacting
playback.
With the Revox A77 you will
retain the excellence of every
recording to enjoy now - and
perhaps appreciate even more in
the future.
So visit your nearest Revox
Dealer for full information and a
demonstration.
Record it on a Revox A77
1
el,
R EVox
ri)
G Admark International
Revox
Revox
Revox
Revox
C. E. Hammond & Co Ltd; Lamb House Church Street London W4 2PB.
Corporation, 155 Michael Drive Syosset N.Y. 11791 U.S.A.
Corporation 3637 Cahuenga Boulevard West, Hollywood California 90068.
International: Regensdorf 8105 ZH, Althardstrasse 146 Switzerland.
CHE
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