Electro-Voice Royal 400 Owner's Manual

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LOW RESONANCE ULTRA-COMPACT LOUDSPEAKER SYSTEM
Elecho Yorez
ROYAL 400
INTRODUCTION
The new Electro-Voice Royal 400 is a 3-way low-resonance
system which, despite its ultra-compact design, provides ex-
ceptionally wide-range response. It contains a special 18”
woofer, the Electro-Voice Model 18WS, utilizing a 4 Ib.,
10 oz. ceramic magnet; an 8” mid-range cone-type speaker,
with a 1 Ib., 6 oz. ceramic magnet; and a compression-type
very high frequency driver. These features make it an ex-
cellent choice for either monaural or stereo reproduction.
Constructed of fine hardwood veneers, the use of heavy,
vibration-free 34” panels gives the Royal 400 unusual rigidity.
SPECIFICATIONS
Nominal Impedance: 8 ohms
Power Handling
Capacity:
Sine Wave: 30-2500 cps., 30 Watts, Maximum;
2500-20,000 cps., 5 Watts, Maxi-
mum.
Program: Maximum undistorted output of 70
Watts amplifier on complex pro-
gram signal.
Frequency Response
Range: 30-19,000 cps. + 4 db.
Components: 187 woofer, 8" extended range
speaker, compression high-frequen-
cy driver, crossover network, two
level controls.
Size: 15” Deep, 27%” High, 2544” Wide.
SCHEMATIC
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Figure 2 Component Wiring
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Mm 108 200 roca 16,006 20.008
Figure 3 Frequency Response, Royal 400 System
Setting Up For Operation
Shipping Damage: Your Royal 400 is packed in accordance
with all shipping requirements of the Interstate Commerce
Commission, plus extra protection. If shipping damage occurs,
contact the carrier directly, requesting inspection and instruc-
tions. Use the date code of the speaker in your correspondence.
Date Code Number: The date code is noted on your warranty
registration card. The number indicates type, style, and date
of manufacture of the unit. Always use this number in your
correspondence.
Warranty Card: To register your Royal 400, fill out the War-
ranty Registration Card and send it to the factory within ten
days after your purchase.
Placement
Nearly any speaker system will sound best if it is placed in
or near the corner of the room in which it is to be used. This
positioning provides the best coupling between the speakers
and the air in the room, the corners and walls acting as a
large “hora” for the sound.
Connections
Connection of your Royal 400 to the amplifier should be
made with No. 18 or larger wire (Common lamp cord is
good). If you wish to run the lead between amplifier and
speaker farther than 30° or to run it behind a moulding strip
or under a carpet, use 300-ohm TV twin lead. Connect to
the 8-ohm and common taps on the back of the amplifier. Be
certain that these connections are secure. Connectors, already
in place between terminals on the Royal (Fig. 4), should be
left in place unless unit is used for stereo reproduction with
E-V Stereon 300 “add-on” unit. Specific instructions will be
found with the Stereon 300.
ROYAL 400
COM 85
ra A rd
AMPLIFIER 60
+59 Qc |
Figure 4 Amplifier Connections
Level Controls
Your Royal 400 is equipped with two controls, a treble
array adjustment and a brilliance control, both of which
are on the rear panel. Set treble array fully clockwise unless
the unit is to be matched in a stereo arrangement with a
speaker of differing efficiency.
Brilliance control setting should usually be at “NORMAL”,
but this may be adjusted to suit the acoustics of the room in
which the Royal is used. A simple, convenient way to adiust
the high-frequency level control is to tune in a live FM
broadcast and listen closely to the announcer’s voice, particu-
larly the “s” and “t” sounds, at a volume level equal to that
of your own speaking voice. Adjust the control until the “s”
and “Y” sounds are no more prominent in the announcer's
speech than they are in yours; such an adjustment will
generally be quite satisfactory. Too high a setting of the
high-frequency control will be audible as a piercing, harsh
“metallic” sound. The best guide, of course, to proper setting
of the control on the speaker system, is a familiarity with the
sound of live music. Most listeners will find it easy to balance
the sound to conform to their personal tastes.
Stereo Operation
Your Royal 400 is designed to give professional quality sound
reproduction. The same performance features which make
this unit outstanding for monaural reproduction will also give
superb performance in stereophonic array.
The wiring connections for a pair of Royals in stereo are
shown in Fig. 5. When connecting be sure to run the lead
from T1 on the Royal to the 8-ohm terminal on the amplifier
and from T2 to the COMMON terminal. With this connection
both units will then be phased correctly.
ROYAL 400 ROYAL 400
T2 TI TZ Ti
C en с вл
AMPLIFIER A AMPLIFIER B
Figure 5 Amplifier Connections For Stereo
Placement For Stereo
When arranging a pair of Royal 400s in stereo array, the
units should be placed at positions which allow the listener to
sit in the area of the apex of a 30° to 40° angle, as shown in
Fig. 6. This will provide the best stereophonic effect. If this
placement is not possible, you may, by experiment, use room
reverberations to advantage in finding other desirable positions.
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Figure 6
BEST Conventional Placement
LISTEKING
POSITION of Speakers for Stereo
SOUND BECOMES
MOMAURAL AT
LONGER DISTANCES
Widening The Stereo Area —
J-Channel Listening
The natural extension of 2-channel stereo reproduction is to
recreate completely the original performance, suitably tailored
to suit the individual taste and listening area.
In stereo recording, great pains are taken to capture full
realism by using 3 microphones to insure complete coverage
of the sound stage. The sound from the microphone in the
center is then “mixed out” to both left and right channels of
recorded sound. From this master recording emerges the
commercially available 2-channel stereo tape or disc.
In these “two track” stereo tapes and discs the element of
this third channel remains and can be reformed by means of
the Electro-Voice XT-1 Stereo Mixer Transformer. XT-1
recovers the center sound from the left and right channels,
adds them together in the correct proportions, and passes
them to the central speaker.
The addition of this third channel to your system gives com-
plete flexibility of seating, in that one can now enjoy good
stereo anywhere in a very large room, or more importantly,
quite close to the loudspeakers in small rooms. At all times,
in virtually any listening position there is a complete curtain
of stereo sound.
Stereons
For those who have space or budget limitations, a Stereon 300
(see next page) can be used with the Royal 400 for either
two- or three-channel stereo. The Stereon 300, which matches
exactly the treble array of the Royal 400, can be used virtually
without compromise in sound by taking advantage of a
natural phenomenon: in 1934, an acoustic engineer, Harvey
Fletcher, determined that sounds from about 300 cycles per
second downwards in the audio spectrum (which have a wave-
length greater than 3% feet) are not intercepted to any per-
ceptible degree by the head; accordingly, the ears find it
impossible to detect the direction from which such sounds
originate. E-V Stereons take advantage of this phenomenon
by using the full bass reproduction capabilities of one full-
range reproducing system for all bass and channelling the
“stereo” sounds (above 200 cps.) correctly to each channel.
The Stereons, then, permit easy and economical expansion to
the stereo system.
The popular approach to E-V Panasound (3-channel stereo
sound) is obtained by using two Royal 400's with one Stereon
300. This arrangement permits the use of two full-range
units, to achieve the fullest bass response. Where space is an
intense problem, good performance can also be achieved by
using a pair of Stereon 300's with one Royal 400.
Complete wiring diagrams for connecting the Royal 400 with
Stereons and XT-1 will be found in the instruction sheets
accompanying the Stereon.
Speaker Repairs
Your Royal 400 system is guaranteed indefinitely against de-
fects in workmanship and materials. Should it become
damaged or develop faulty operation from unusual con-
ditions of use, Electro-Voice maintains a complete service
department to put equipment in factory-new conditions. Please
write for authorization and shipping instructions before re-
turning any equipment. Be sure to give full name and
address together with a short description of the difficulties
in your system.
Technical Service
The firm from which you purchased your equipment knows
thoroughly the application of Electro-Voice products and
high-fidelity stereo techniques. His advice on the installation
of Electro-Voice components and on the selection of associ-
ated high-fidelity equipment will be invaluable. Technical
problems which cannot be answered locally may be referred
to:
MANAGER, CONSUMER PRODUCTS DIVISION
Electro-Voice, Inc.
Buchanan, Michigan
When writing, please list the manufacturer and model number
of all components used in your high-fidelity system.
HIGH FIDELITY ACCESSORIES
SUGGESTED FOR USE WITH THE ROYAL 400
For more than 35 years, Electro-Voice has been a leader in the develop-
ment and manufacture of dynamic microphones and loudspeakers. Why
then, with this extensive experience in designing and producing electro-
magnetic devices, 1s Electro-Voice introducing the new Magneramic 31
Series stereo cartridge using ceramic elements? Electro-Voice is genuinely
convinced that a precision ceramic cartridge is the finest type that can
be made today . . . the superiority of the E-V Ceramic, Magneramic 31,
is demonstrated in these three areas:
(1) Greater Flexibility — The 31 Series cartridge will operate per-
fectly at any stylus pressure from 2 to 20 grams. The same stylus assem-
bly can be used for operation of both turntable and record changers;
performance need not be compromised by using a special, stiff stylus
a assembly for record changers. Record wear is the only criterion in setting
ЗАО stylus pressure — cartridge operation is not affected. Thus, when con-
E verting from a changer to a turntable, or vice versa, replacement of the
stylus assembly is not necessary when using the Magneramic 31.
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(2) Higher Output — Along with the trend toward less efficient speaker systems, more amplifier power has become a
necessity. While most stereo amplifiers are now designed with input sensitivities to match the typical 5 millivolt output of mag-
netic stereo cartridges, nearly all monaural amplifiers were designed for at least 8 millivolt input. These cannot be driven to full
output with a magnetic stereo cartridge.
The Magneramic 31 develops a full 8 millivolt output and couples directly into any magnetic preamp unit. This higher output
should be given special consideration by those planning to convert to stereo with existent monaural amplifiers.
(3) Freedom from Hum. — The increased amplifier gain required to drive low efficiency speakers coupled with decreased
cartridge output has significantly increased system hum problems. Also, conventional methods of hum elimination used in mon-
aural magnetic cartridges become difficult or impossible to apply to stereo magnetics. The Magneramic 31 completely elimi-
nates these problems. It is non-inductive and has adequate output.
The Electro-Voice Magneramic 31MD7 cartridge directly replaces any monophonic or stereophonic magnetic cartridge now
on the market. It feeds into the preamp input jack specified for magnetic cartridges and does not require adapter or circuit
modifications.
SPECIFICATIONS — MAGNERAMIC 31MD7
Response Range: 20 to 15000 cps. + 2 db (Westrex 1A) Output: 8 millivolts
Compliance, Vertical: 3,5 x 106 cm/dyne Recommended Load: 22,000 to 47,000 ohms (Magnetic phono
Compliance, Lateral: 3.5 x 108 cm/dyne inputs)
Isolation: 28 db @ 1000 cycles Elements: 2, lead Zirconium Titanate (Ceramic)
Tracking Force: 2 to 4 grams in transcription arms Weight: 8 grams
4 to 6 grams in changer arms Terminals: 4, standard .050” connectors
Styli: .7 mil diamond Mounting Centers: Fits both 1/2" and 7/16”
Audiophile Net $24.00
Want more information? Send for the booklet, "FACTS ABOUT THE ELECTRO-VOICE Magneramic Cartridge.”
Model XT-1 Stereo Mixer Transformer
For use with the Stereon 300 and Royal 400. Only one required
for two- or three-channel stereo system.
Audiophile Net $13.50
Stereon 300
A two-way system consisting of a Radax extended-range speaker,
together with a diffraction horn very high frequency driver. Oper-
ates with the Royal 400 in two- or three-channel sterecphonic
systems.
Audiophile Net $69.50
Electo occ | ELECTRO-VOICE, INC. / BUCHANAN, MICHIGAN
KLIPSCH LICENSED CORNER HORN LOADING.
DESIGNED FOR 15% COAXIAL SPEAKERS, AND SEPARATE
2-WAY AND 3-WAY SYSTEMS — without modification.
ONE FULL OCTAYE OF ADDED BASS GUARANTEED OVER
ANY COMMERCIALLY AVAILABLE BASS REFLEX
ENCLOSURE,
UNPRECEDENTED EFFICIENCY — LABORATORY FLATNESS
= 5 db to 30 cps! 10 to 15 db more efficient than conven-
tional enclosures!
MODERATELY PRICED.
— Authentically styled, the motif of the ROYAL is
at once conservative, but appealing as a design of excellence and en-
during beauty. Adaptable to the living room, study or den, the exquisite
mahogany veneers are hand-rubbed to a mirror Heirloom finish on
every exposed surface. The workmanship reflects all the pride and
consummate skill of the ELECTRO-volcE master craftsmen. Available,
too, in smart lustrous Korina blonde. To promote further the decorative
scheme of the ROYAL, the attractive, solid grille is formed of lacquered
metal in brushed brass antique,
The spatial requirements of the very highest fidelity reproduction are
conserved to the fullest. The trim size of the ROYAL Will afford an
agreeable surprise.
Proportions of the ROYAL are based on the established precepts of
dynamic symmetry; the corner of the room, for which fumiture usually
is not designed, is incorporated functionally as a part of the housing,
enhancing not only the appearance of the ROYAL, but forming also a
very vital part of its employment.
ts TA ‘= Recognizing the maxim which dictates that the
quality of a music reproducing system is proportionate to its size,
ELECTRO-VOICE physicists and engineers have, through unique design,
hidden the bulk of the acoustic system of the ROYAL. The very walls of
the living room have been employed as an extension af this compact and
beautiful reproducer. The result is a performance so vibrant and vital
that the first listening purveys an utterly new emotional experience.
YOU ARE INVITED to a command performance by the rovaL! Plan
to hear this new concept in design at your ELECTRO-VOICE dealer today
— then — let your own ears be the judge.
re Scientifically correct propoga-'
tion of the first 3 octaves, or those frequencies included between 16 and
128 cycles per second, requires that the cone of the low-frequency
driver be loaded with a column of air of relatively huge dimensions.
For instance, the smooth reproduction of a 50 cycle tone requires that
the cross-sectional area at the mouth of this column be 14 wavelength
of this frequency, or 80 inches At 30 cycles this dimension is 111
inches! It is quite apparent that a structure capable of housing a horn
shape of this large size precludes its use in a living room.
Several years ago Paul W. Klipsch invented the exponential folded
corner horn, which employed the walls of the room as an extension of
a horn throat cleverly concealed in a furniture housing. This effectively
permitted extended bass range reproduction in a room of reasomable
dimensions for the first time.
But one thing more was necessary. Although the bass range was ex-
tended, efficiencies were Jow —only LA to 14 of the necessary power
for achieving musical balance with reasonable economy of amplifier
power and equalization, Accordingly, Electro-Voice scientists partici-
pated with Paul W, Klipsch in the development of super-low resonant
bass drivers. The unique high compliance, or capacitive factor of these
units 1s designed to match the mass, or inductance of the air in a care-
fully-calculated chamber immediately in back of the cone. The combina.
tion results in a very broad 4 octave pass-band circuit. This circuit
becomes acoustically resonant when the ROYAL 15 coupled to the room
air load by placement in a corner, Ап advantage of this discovery is
the unequalled damping of the driver cone. The large resistive airload
prevents voice coil override with attendant non-liner distortion, holds
the voice-coil efficiently in the region of most dense gap-fux and
bermits better than a 50% higher power rating on the driver!
Through these means the ROYAL delivers phenomenally wide range bass,
virtually perfect, peak-free and 1009 full powered, It generates ex-
tended bass tones at the necessary full level of efficiency with purity
never attained before commercially in the living room. It performs this
function without the characteristic peaks and null points of narrow
range, ‘one-note” bass-reflex enclosures,
ROYAL FOLDED HORN CORNER
LOUDSPEAKER ENCLOSURE, only
In hand-rubbed mahogany veneers. List... $180
In blonde Korina wood. List $190
*Licensed under Klipsch Patent Nos. 2310243 and 2373697
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When the music lover first hears the E-V ROYAL п REPRODUCING
SYSTEM, he is delighted to discover its breadth of response range...
literally feeling the physical impact of timpani and tuba. Yet, he is
instantly aware that this tremendous bass capacity is balanced by spar-
kling, brilliant reproduction of the delic#te treble tones of the highest
audible registers. A second hearing discloses that this is but an intro-
duction to the ROYAL I's superb performance. He hears a cleanliness of
reproduction that lends third dimensional quality to the music...
heightening the illusion of presence.
And then listening carefully for favorite musical passages, he learns
how the ROYAL If handles difficult flights of orchestral fancy with a
distortion-free fidelity quite unlike that experienced before. Then he
appreciates why music lives when recreated by this remarkable sound
reproducing system.
The ROYAL п is à complete audio package ready for connection to the
amplifier. It includes the E-V MODEL 114 SEPARATE 2-WAY SPEAKER
SYSTEM installed in the ROYAL FOLDED HORN CORNER ENCLOSURE. The
ROYAL enclosure is smartly styled and hand-finished in either rich ma-
hogany or blonde Korina wood. Each component of the royAL n
REPRODUCING SYSTEM contributes a specific virtue to the overall per-
formance. The purpose and technical specifications of these components
are described individually.
ROYAL II, AN 800 CPS SEPARATE 2-WAY
SOUND REPRODUCING SYSTEM
In Mahogany Royal Enclosure, Liste. $465
In Blonde Royal Enclosure. List $475
SPECIFICATIONS, ROYAL IT SOUND REPRODUCER
ation system which divides the reproduced spectrum between disparate
drivers by crossover networks of the lowest possible frequency.
The Model 114 SEPARATE 2-WAY SPEAK-
ER SYSTEM achieves the fnest results
possible from live FM, recorded tape or
vynilite disc sources. Low, powerful,
extended bass is produced by the E-V
Model 15W row FREQUENCY DRIVER.
The Model X-8 CROSSOVER NETWORK
restricts low frequencies to the bass
driver and directs tones above 800 cps
to the Model T-25 HIGH-FREQUENCY
pRIVER. The treble driver exhausts
through the Model 8-HD DIFFRACTION
HORN, which distributes upper octave
tones through a solid angle of 180”.
The Model 114 sYSTEM is an acoustically balanced sound generating
component for the ROYAL © SOUND REPRODUCER. It is an equally fine
driver unit for custom installations in walls or "built-in" cabinets, or
for existing enclosures. The individual components of the Model 114
SYSTEM are available separately, also.
MODEL 114 800 CPS SEPARATE 2-WAY
LOUDSPEAKER SYSTEM. List $285
SPECIFICATIONS, MODEL 114 SPEAKER SYSTEM
Includes Model 15W Bass Driver, Model T-25 Treble Driver, Model 8-HD
Horn, Model X-8 Crossover Network, Flot Boffle Board and Medel AK-1
Mounting Kit. For installation in E-V Royal Corner Enclosure or in existing
cabinets or walls.
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COMPONENT SPECIFICATIONS
HIPPING: 78 lbs.
In the ROYAL CORNER ENCLOSURE, the MODEL I5W LOW-FREQUENCY
DRIVER reproduces bass tones down to 16 cps with high efficiency! The
high compliance, or acoustical capacitance of the driver, perfectly
matches the inductance of the back
chamber air mass of the enclosure. This
permits the formation of a broadly res-
onant circuit in conjunction with the
frontal air load.
The unusually high compliance of both
the outer cone rolls and inner spider of
the Model 15W provides a fundamental
resonance in free air of 37 cps. This
means that the 18 db per octave roll
off, or drop in acoustical output com-
mon to all cone or diaphram type gener-
ators, starts at a much lower frequen-
cy. The stiff, straight sided 27 oz. cone
is extra strong, thus preventing relaxa-
tion of the suspension material along its length. This precludes the
formation of spurious sum and difference tones, a result of the outer
area moving at a slower rate than the central fundamentally excited
area, The Model 15W uses the largest Alnico V magnet to be found
in any commercially available 15" low-frequency driver, guaranteeing
the highest efficiency and freedom from voice coil override, This re-
duces to 2 minimum the attendant transient distortion. The Model 15W
BASS DRIVER is ideal for improving existing speaker systems too, No
other 15” low-frequency driver is its equal in efficiency, extended low
range, and distortion-free characteristic.
MODEL I5W DRIVER. List
$120
DIMENSIONS OF BAFFLE BOARD: 33%'* high, 22
ide, %"" plywood. WEIGHT INCLUDING ALL COMPONENTS, NET: 577:
$
a
SPECIFICATIONS, MODEL 15W LOW-FREQUENCY DRIVER
RTMA SENSITIVITY RATING: 49 db. RESPONSE RANGE: To 30 cps + 5db
in E-Y Royal Enclesure in overage size living room; to 35 cps + 5 db on flot
infinite baffle. SHORT DURATION PEAK POWER INPUT: 50 watts in Royal
Enclosure; 35 watts on flot baffle. CONTINUOUS PROGRAM level; 35
watts. IMPEDANCE: 16 ohms at 400 cps. RESISTANCE: 11.3 ohms DC
FREE AIR CONE RESOMANCE: 37 cps. CONE WEIGHT: 27 ox:
DIMENSIONS: 37'' high, 2334"' wide, 20/:" deep: WEIGHT, NET: 126" Ibs.
SHIPPING: 1362 Ibs.
moisture and fungi-proofed. FIELD STRENGTH: 14,300 lines/sq. cm. MAGNÉ
WEIGHT: 514 Ib Alnico Y. MAGNET STRUCTURE WEIGHT: 27 Ibs. BINDING
POSTS: Positive, morked red ond Negative, marked block for forward
motion of cone with dry cell applied. MOUNTING DIMENSIONS: four 3"
; ее ; holes spaced 70” apart on 1434" circle, - DIMENSIONS: 15'3'' diometer,
To recreate the synthesis of the original music, a speaker system must 87%" deep behind mounting panel, 137” baffle opening. WEIGHT, NET:
reproduce all the original frequencies with a minimum of harmonic, 34% lbs; SHIPPING: 44 Ibs.
intermodulation -and transient distortion. This requires a sound gener-
General: In order to reproduce the rapid delicate pulses of the upper
octaves, the vibrating or piston member of a high-frequency driver must
be light, and thus small. On the other hand, to achieve useable power
transfer the diaphram assembly must be large and consequently heavy.
These irreconcilable requirements have limited the high range of driver
units in the past; the usual roll-off of a 40 watt 214 inch diaphram
being 3000 cps, and that of 25 watt 114 inch diaphram about 4500 cps.
Resonant cavities are frequently introduced to gain augmented response
several thousand cycles higher, but with accompanying raggedness in the
reproducing characteristic and sharp attenuation after the resonant
peak. Another factor entering into this
complicated design problem is the vio-
lent phasing-out of the acoustic energy
at certain frequencies. This phenomenon
transpires when the signal approaches
in wavelength twice that of the diame-
ter of the diaphram. The unfortunate
circumstance thus experienced drastically
affects listening quality, which demands
a rise of between 5 and 10 db in this
region (5000 KC).
ELECTRO-VOICE High-Frequency units completely by-pass thesz seem-
ingly snsurmountable design difficulties] Lewis Hoodwin, a brilliant
physicist on the ELECTRO-VOICE engineering staff, has invented the unique
loading device for the HF diaphram,
whereby the effect of diaphram diameter
is no longer a factor. The accompanying
sketch shows that the usual cavity in
the piston region has been eliminated.
The throat of the acoustic system be-
gins directly at the voice coil where it
is joined to the diaphram; thus, for the
first time, a true scientific exponential
flare takes place from the very origin
of the sound source, This results in
the greatest transfer efficiency, and the
smoothest, most extended high frequency response available on the mar-
ket today. The phenolic moulded and cloth impregnated diaphram has
tremendous strength and can be overloaded to the point of voice coil
disintegration without fracture. Furthermore, it is not susceptible to
the radial splitting and buzzing common to delicate aluminum diaphrams.
MODEL T-25 DRIVER. Lisf.....................$ 90.00
BLACK AREA 5 EXPANDING ACOUSTIC paTH
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For the first time, the superior high-frequency dispersion characteristics
of the Diffraction Principle are available in a compact horn suitable
for home high fdelity systems. In order properly to load the driver
diaphram, an exponential horn is re-
quired of the proper flare. In addition
the high frequencies which would or-
dinarily beam straight down the axis
must be adequately dispersed in order
to cover the entire listening area. In
the past this dispersion has been mea-
gerly effected by a multiplicity of cells,
each pinpointing a spot in the room, usually 8 in number. Each cell
intercepts a solid angle of 20° at about 2 KC; at 10 KC this angle is
only about 10°. In keeping with the requirements of the discrim-
inating listener, ELECTRO-VOICE
has developed the Diffraction
Principle of high-frequency sound
dispersion. The employment of
this principle in the Hoodwin
horn design effects better than
180° of dispersion, sans all pin-
pointing effects, and does this
with more efficiency at all fre-
quencies. The MODEL 8-HD HORN,
in addition, has a wide margin
of safety near the recommended
crossover frequency of 800 cps;
the horn is designed actually
with a 600 cps cut-off, thus
eliminating the response disturb-
ances associated with operation
too near the actual cut-off point.
A most important feature of the
HOODWIN HORN is the increased
efficiency of 3 db, or double that of conventional cellular horns. This
is brought about by the elimination of the viscous resistivity of the air
engendered by the multiplicity of throats at the driver unit mouth. The
horn design uses the new material Fibreglas, noted for its fine acoustic
properties and extreme ruggedness.
MODEL 8-HD HORN. List
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SPECIFICATIONS, MODEL 8-HD DIFFRACTION HORN
SPECIFICATIONS, MODEL T-25 H. F. DRIVER
RTMA SENSITIVITY RATING: 48 db. RESPONSE RANGE: to 15,000 cps
with efficient response; to 11,000 eps + 5 db. SHORT DURATION PEAK
POWER INPUT: 50 watts above B00 cps. CONTINUOUS PROGRAM
MATERIAL: 25 watts. PROGRAM MATERIAL ABOVE 400 CPS: 20 watts.
IMPEDANCE: 16 ohms at 400 cps. RESISTANCE: 10.5 ohms DC. DIAPHRAGM
DIAMETER: 1'2"", diaphragm is phenolic moulded and cloth impregnated for
tremendous strength. Not susceptible to radial splitting and buzzing as are
delicate aluminum diaphragms. Can be overloaded to point of voice coil
disintegration without frocture. FUNDAMENTAL RESONANCE: 275 cps.
FIELD STRENGTH: 1% Ibs. Alnico V magnet. MOUNTING DIMENSIONS:
Two 5/16-18 tapped holes spaced 180° apart on 2" circle or four 5/16-18 a
tapped holes spaced 90° apart on 3'' circle. DIMENSIONS: 5'' diameter, : =
deep, 7a"" throat diameter. WEIGHT, NET: 10 ibs; SHIPPING: 16 Ibs.
DISPERSION: 180°. ACTUAL CUTOFF: 600 cps. RECOMMENDED CROSS-
OVER POINT: 800 cps; eliminates response disturbances associated with
operation too near actual cutoff point. APPLICATION: for 25 watt or 10
watt treble drivers. MOUNTING DIMENSIONS: two 5/16-18 holes spaced
180° Cll en 2'' circle. Uses AK-1 Mounting Kit for a panel mounting.
[List price AK-1 Kit . . . 55) DIMENSIONS: 34°" hor co 1474" Led AZ
deep, Va" throat opening. WEIGHT, NET: 1 Ib; SHIPPING: lbs.
Reproduction so clear, so vibrant that the illusion of “presence” pre-
vades the room ...yours with the SUPER-FIFTEEN. This large 15-inch
speaker is capable of receiving and transmitting the tremendous energy
from the lower portion of the audible spectrum. A mechanical cross-
Utilizes the standard circuit employed
by the motion picture industry, the full
m derived 15 section configuration, Re-
stricts low-frequencies to bass driver,
and directs high frequencies to treble
driver. M is .6. Attenuation is a 12 db
per octave each side of crossover point,
presenting an optimum degree of at-
tenuation with minimum possibility of
transient distortion generation. Utilizes
air-cored coils to eliminate distortion with varying load and frequency.
Q is better than 150. Condensers are paper type with generous over-
load factor. Insertion loss is less than 1 db. Phase rotation is 270°.
MODEL X-8 CROSSOYER NETWORK.
List $ 50.00
SPECIFICATIONS, MODEL X-8 CROSSOVER NETWORK
POWER RATING: 60 watts, IMPEDANCE: 16 ohms for input, ond high and
low autput. DIMENSIONS: 8'° long, 52" wide, 4/2" high. WEIGHT, NET:
4-7 Ibs; SHIPPING: & (bs.
over, operating at the sixth octave di-
rects the sensitive high-frequency pulses
of the treble register to the smaller
RADAX high-frequency propagator. RADAX
generates and distributes the highest
four octaves without loss of level. By
dividing the spectrum between two spe-
cially designed coaxial diaphrams the
Radax Principle assures music in flaw-
less proportion and balance throughout
the entire listening area.
Power or efficiency is many times that
of conventional one-way speaker units
.actual acoustic power is seven to
eight times higher! The heavy speaker
frame is accurately machined and polished for improved voice coil oper-
ation and extended, trouble-free life. The. SUPER-FIFTEEN is a fitting
complement to the finest amplifiers. (SP-15, continued on last page)
To reproduce the powerful impact of the bass drum, the loudspeaker
must move large volumes of air. Transmission of the lowest frequency
range is proportional to the size of the bass diaphram and the design of
its enclosure. The SUPER-FIFTEEN will transmit sounds as low as 30
cycles per second without level disparagement. To the listener, this
means faithful reproduction of the deep, resonant tones of the contra-
bassoon, bass drum and tuba. And an acoustically proper enclosure for
this splendid ffteen-inch system need contain only nine cubic feet of
space. The E-V ROYAL cabinet, for instance, designated with ideal
dimensions, makes a graceful appointment in any room. Reproduction
of the high frequencies is best obtained from a small diaphram capable
of vibrating small volumes of air, but with great rapidity, When the
generation of these delicate pulses is consigned to a large cone, heavy
and stiff enough to receive the tremendous energy of tympani, the vital
sparkling tinkle is masked and lost.
In the E-V super FIFTEEN this apparent inconsistency-is completely
resolved by the Radax Principle. The 15-inch bass cone is freed of all
but the full, sonorous tones it can produce so well. A mechanical cross-
over transfers the sounds of the upper octaves to the small, lightweight
high-frequency propagator, This divides the musical spectrum and
provides uncompromised emphasis to both low and high registers,
maintaining pleasing proportion between bass and treble.
To assure full response from the two disparate driving cones, the
MODEL SP-15 utilizes a large 214 inch voice coil and massive 514
pound Alnico V Magnet. The high damping factor, made possible by
the oversized magnet, spider, and stiff bass cone, suppresses the genera-
tion of distortion products.
Where baffle areas must be held within smaller limits, the RADAX
SUPER-FIFTEEN makes an ideal component for installation by the custom
builder who requires distinguished performance. It will provide full
range sound reproduction for churches, school anditoriums and highest
quality public address installations... specifications exceed those of the
Research Council of the Academy of Motion Picture and Sciences for
theaters up to 750 seat capacity.
MODEL SP15, 15" COAXIAL LOUDSPEAKER SYSTEM. Lisf............. $120.00
SPECIFICATIONS, MODEL SP-15 LOUDSPEAKER SYSTEM
FREQUENCY RESPONSE RANGE: 30 to 13,000 eps + 6 db in E-V Royal Enclosure. SHORT DURATION PEAK POWER INPUT: 35 watts. INPUT
IMPEDANCE: 16 ohms + 40 percent with amplifiers employing feed-back.
BASS CONE RESONANCE: 41 cps. TREELE CONE RESONANCE:
250 cps. RADAX CROSSOVER FREQUENCY: 3000 cps. FIELD EXCITATION: 51/, Ib Alnico ¥ Magnet, MAGNET STRUCTURE WEIGHT: 27 Ibs.
FEATURES: Boss and treble cones are specially treated for moisture and fungus protection. Cones are compliance damped to prevent frame
reflections from reinforcing or cancelling certain frequencies. Heavy frome costing is occurately machined. Speaker pot structure finished E
in irridescent maroon hammertone. BINDING POSTS: Positive, marked red;
negative, marked black for forward motion of cone with dry cell
upplied. DIMENSIONS: 151/41" diameter, 87" depth behind mounting panel, 131:'' bafle opening. WEIGHT, NET: 35 Ibs; SHIPPING: 44 Ibs.
ELECTRO-VOICE is the only speaker manufacturer so far to publish
authentic, unretouched, machine-run response curves of its products.
The industry in the past has been reluctant to do this because the test
conditions influence the character of the results. Furthermore, it is
recognized that the significance of curves leaves considerable to be de-
sired in the subjective evaluation of loudspeaker performance. A satis-
factory degree of correlation can be established by careful interpretation,
however, and an attempt is made to achieve this correlation in the short
notes covering the measurements shown below.
: "An anechoic chamber was employed of the
dimensloa 12’ x 12’ x 20’, with a standard calibrated microphone. Im-
pedance measurements were made in a simiblated living room 12' x 14’
x 9" using a Ballantyne Voltmeter across the voice coil with 100 ohms
in series,
(== /\ ELECTRO -VOICE, INC. ©
Printed in U.8.A. Bulletin No. 183
Because the anechoic chamber does not permit the inclusion of the
walls of a room, the response curve is a composite of anechoic chamber
above 100 cps, and the simulated living room below this point. Ob-
serve that a 5 db dip is introduced in the design exactly at 60 cps to
reduce the effects of turntable rumble, Augmented response in the
“presence” region 3-6 КС is satisfactorily introduced to offset ear
insensitivity at room reproducing levels. Sensitivity, or efficiency, is
measured by the recommended method established by the Radio and
Television Manufacturers’ Association.
The same anechoic chamber and microphone
was чета, in addition. to a Model TI-401 signal generator and a
Model TI-402 distortion analyzer. For the intermodulation distortion
tests a carrier signal of 60 cps was employed modulated by 2, 7 and
12 KC with a ratio of 4:1.
O MAa MOM Amos
Although the most modern equipment was used in this distortion anal-
ysis, its value in measuring distortion products in loudspeaker systems
is open to considerable question. For instance, the only available and
arbitrary modulating frequencies could be the weakest points in the
design distortion-wise, and every other frequency point might be com-
paratively distortion free; thus a very fine speaker could show up
poorly. The converse is also possible. For the arbitrary points shown,
the distortion in the ROYAL I SYSTEM and sP-15 RADAX is unusually low
compared with other commercially available quality systems.
Your E-V Distributor
— Buchanan, Michigan
NN Á / Export, 13 East 40th Street, New York 16, N. Y. USA, Cables, Arlab