Meyer Sound | LD-2 | Operating instructions | Meyer Sound LD-2 Operating instructions

Meyer Sound LD-2 Operating instructions
LD-2
Line Driver
OPERATING
INSTRUCTIONS
OPERATING INSTRUCTIONS
Superior
engineering
for the art
and science
of sound.

Keep these important operating instructions
CONTENTS
Safety Summary
The LD-2 Line Driver: Introduction
Audio Input
AC Power
Left And Right Channel Funtions
Example Configurations
Specifications
LD-2 Signal Flow Diagram
Front and Rear Panel Detail, Physical Dimensions
Notes
Contact Information
3
4
4
5
5
6
8
9
10
11
12
SYMBOLS USED
THESE
SYMBOLS INDICATE IMPORTANT SAFETY OR OPERATING FEATURES IN THIS BOOKLET AND ON THE CHASSIS.
!
Dangerous voltages:
Important operating
risk of electric shock
instructions
Pour indiquer les risques résultant
Pour indequer important
de tensions dangereuses
instructions
Zu die gefahren von
gefährliche spanning zeigen
Para indicar azares provengo
de peligroso voltajes
Frame or chassis
Protective earth ground
Masse, châssis
Terre de protection
Zu wichtige betriebsanweisung und unterhaltsanweisung zeigen
Rahmen oder chassis
Die schutzerde
Para indicar importante
funcionar y mantenimiento
instrucciones
Armadura o chassis
Tierra proteccionista
DECLARATION OF CONFORMITY ACCORDING TO ISO/IEC GUIDE AND EN 45014
E NVIRONMENTAL S PECIFICATIONS FOR M EYER S OUND E LECTRONICS P RODUCTS :
Operating Temperature 0° to + 45°
Nonoperating Temperature <-40°C or > +75°C
Humidity to 95% at 35°C
Operating Altitude to 4600 m (15,000 ft)
Declares that the product:
Nonoperating Altitude to 6300 m (25,000 ft)
Shock 30g 11 msec half-sine on each
of 6 sides
Vibration 10Hz to 55Hz (0.010m
Conforms to the following Product Specifications
peak-to-peak excursion)
Safety:
EN60065: 1994
1
EMC:
EN55103-1 emmission
Made by Meyer Sound Laboratories
EN55103-2 immunity2
3K59 COMMERCIAL
Berkeley, California USA
The Manufacturer:
MEYER SOUND LABORATORIES, INC.
2832 San Pablo Avenue
Berkeley, California 94702-2204, USA
LD-2
AUDIO SYSTEM
This device complies with the requirements of the Low Voltage
Directive 73 / 23 / EEC and the EMC Directive 89 / 336 / EEC.
This device also complies with EN 55103-1 & -2. Operation is
subject to the following two conditions:
(1) this device may not cause harmful interference, and
(2) this device must accept any interference received, including
interference that may cause undesired operation.
2
European Office:
Meyer Sound Lab. GmbH
Carl Zeiss Strasse 13
56751 Polch, Germany
N757 LD-2
Office of Quality Manager
Berkeley, California USA August 31, 2000
!
ENGLISH
• To reduce the risk of electric shock,
disconnect the unit from the AC
mains before installing audio cable.
Reconnect the power cord only after
making all signal connections.
• Connect the unit to a two-pole, three
wire grounding mains receptacle. The
receptacle must be connected to a
fuse or circuit breaker. Connection to
any other type of receptacle poses a
shock hazard and may violate local
electrical codes.
• Do not allow water or any foreign
object to get inside the unit. Do not
put objects containing liquid on, or
near, the unit.
• To reduce the risk of overheating the
unit, avoid exposing it to direct
sunlight. Do not install the unit near
heat-emitting appliances, such as a
room heater or stove.
• This unit contains potentially
hazardous voltages. Do not attempt
to disassemble the unit. The unit
contains no user-serviceable parts.
Repairs should be performed only by
factory-trained service personnel.
FRANÇAIS
• Pour réduire le risque d’électrocution,
débrancher la prise principale de
appareil, avant d’installer le câble
d’interface allant à l’audio. Ne
rebrancher le bloc d’alimentation
qu’après avoir effectué toutes les
connections.
• Branchez appareil dans une prise de
courant à 3 dérivations (deux pôles et
la terre). Cette prise doit être munie
d’une protection adéquate (fusible ou
coupe-circuit). Le branchement dans
tout autre genre de prise pourrait
entraîner un risque d’électrocution et
peut constituer une infraction à la
réglementation locale concernant les
installations électriques.
• Ne pas laisser de l’eau ou tout objet
SAFETY SUMMARY
pénétrer dans appareil. Ne pas placer
de r´cipients contenant un liquide sur
cet appareil, ni à proximité de celuici.
• Pour éviter une surchauffe de
appareil, conserver-la à l’abri du
soleil. Ne pas installer à proximité
d’appareils dégageant de la chaleur
tels que radiateurs ou appareils de
chauffage.
• Ce appareil contient des circuits haute
tension présentant un danger. Ne
jamais essayer de le démonter. Il n’y a
aucun composant qui puisse être
réparé par l’utilisateur. Toutes les
réparations doivent être effectuées
par du personnel qualifié et agréé par
le constructeur.
DEUTSCH
• Um die Gefahr eines elektrischen
Schlages auf ein Minimum zu
reduzieren, den Gerät vom Stromnetz
trennen, bevor ggf. ein AudioSchnittstellensignalkabel
angeschlossen wird. Das Netzkabel
erst nach Herstellung aller
Signalverbindungen wieder
einstecken.
• Der Gerät an eine geerdete zweipolige
Dreiphasen-Netzsteckdose
anschließen. Die Steckdose muß mit
einem geeigneten Abzweigschutz
(Sicherung oder Leistungsschalter)
verbunden sein. Der Anschluß der
unterbrechungsfreien Stromversorgung
an einen anderen Steckdosentyp kann
zu Stromschlägen führen und gegen
die örtlichen Vorschriften verstoßen.
• Darauf achten, daß weder Wasser
noch Fremdkörper in das Innere den
Gerät eindringen. Keine Objekte, die
Flüssigkeit enthalten, auf oder neben
die unterbrechungsfreie
Stromversorgung stellen.
• Um ein Überhitzen dem Gerät zu
verhindern, das Gerät vor direkter
Sonneneinstrahlung fernhalten und
3
nicht in der Nähe von
wärmeabstrahlenden Haushaltsgeräten
(z.B. Heizgerät oder Herd) aufstellen.
• Im Inneren diesem Gerät herr-schen
potentiell gefährliche Spannungen.
Nicht versuchen, das Gerät zu öffnen.
Es enthält keine vom Benutzer
reparierbaren Teile. Reparaturen
dürfen nur von ausgebildetem
Kundenienstpersonal durchgeführt
werden.
ESPAÑOL
• Para reducir el riesgo de descarga
eléctrica, desconecte de la red el
aparato antes de instalar el cable de
señalización de interfaz de la segnale.
Vuelva a conectar el conductor
flexible de alimentación solamente
una vez efectuadas todas las
interconexiones de señalizatción.
• Conecte el aparato a un tomacorriente
bipolar y trifilar con neutro de puesta
a tierra. El tomacorriente debe estar
conectado a la protección de
derivación apropiada (ya sea un
fusible o un disyuntor). La conexión a
cualquier otro tipo de tomacorriente
puede constituir peligro de descarga
eléctrica y violar los códigos
eléctricos locales.
• No deje que en el aparato entre agua
ni ningún objeto extraño. No ponga
objetos con líquidos encima de la
unidad ni cerca de ella.
• Para reducir el riesgo de
sobrecalentamiento, no exponga la
unidad a los rayos directos del sol ni
la instale cerca de artefactos que
emiten calor, como estufas o cocinas.
• Este aparato contiene niveles de voltaje
peligrosos en potencia. No intente
desarmar la unidad, pues no contiene
piezas que puedan ser repardas por el
usuario. Las reparaciones deben
efectuarse únicamente por parte del
personal de mantenimiento capacitado
en la fábrica.
THE LD-2 LINE DRIVER:INTRODUCTION
Thank you for purchasing the LD-2 Line Driver, one of the two
line-level distribution systems offered by Meyer Sound for
integrating and optimizing our self-powered loudspeakers. The
LD-2 allows system designers and operators to configure and
control Meyer Sound self-powered full range, mid-hi, mid-bass,
downfill, and subwoofer loudspeakers and any combination of
these devices that may be required for real-world sound
reinforcement or playback applications. The LD-2 provides the
same basic functions as those provided by the LD-1A, but in a
more compact package for those sound system applications
requiring fewer auxiliary or supplemental loudspeakers.
Filter Switch
In
Filter Switch
Out
Mid-Bass or AUX
Output
Sub
Output
Figure 1 Mid-Bass or AUX and Sub Crossover
The LD-2 provides two discrete distribution channels (Left and
Right) and each of these is equipped with a master gain
control, a master mute switch, and LED indicators to show the
presence of input signal, clipping and muting status. The gain
and mute controls on each input affect their associated
output channels. Additionally, each of the six output channels
is equipped with an individual gain control, mute switch and
application-specific switched filters. Each output may be
utilized as a full-frequency distributed output with gain and
muting control or may be configured as Mid-Hi, Mid-Bass, and
Sub (woofer) outputs, with appropriate filters. The Mid-Hi
output is equipped with a 160Hz Low Cut filter for
applications utilizing Meyer Sound Mid-Bass loudspeakers (DS2P or DS-4P). This output is also equipped with a switched
Array EQ filter to minimize the increased low-mid frequency
output resulting from combined adjacent loudspeakers such as
horizontal arrays of MSL-4 loudspeakers. The Mid-Bass and Sub
Crossover switch provides filters to the second and third
outputs to facilitate employment of Meyer Sound mid-bass
loudspeakers (DS-2P or DS-4P) and Meyer Sound subwoofers
(650-P or PSW-2), or both (See Figure 1).
In applications where mid-hi loudspeakers are used in
conjunction with subwoofers (with no supplemental mid-bass
loudspeakers), the Mid-Bass/AUX output channels may be
employed to feed auxiliary full range or downfill loudspeakers.
The Low Cut filter on this output will further optimize the
frequency response of mid-hi/full range cabinets connected to
the Mid-Bass/AUX output channel.
The LD-2 occupies one rack space and is constructed with a
16-gauge steel chassis and 1/8" aluminum rack ears. This
rugged design provides protection from physical wear and tear
and immunity from EMI.
MEYER SOUND LOUDSPEAKER TYPES
The following Meyer Sound self-powered loudspeakers are
referenced in this document. Please note that the MSL-4 is
normally employed as and considered to be a "full range"
loudspeaker. As used in the loudspeaker applications
described below (wherein there are supplemental “mid-bass”
and/or “subwoofer” loudspeakers) the MSL-4 is referred to
more accurately as a "mid-hi" loudspeaker.
•
•
•
•
•
•
4
MSL-4 mid-hi loudspeaker
CQ Series full range loudspeaker
DS-2P/4P mid-bass loudspeaker
DF-4 downfill loudspeaker
650-P subwoofer
PSW-2 subwoofer
AUDIO INPUT
The LD-2 presents a 10Ω balanced input impedance to a
three-pin XLR connector wired with the following convention:
Case — Earth (AC) ground and chassis
Pin 1 — Earth (AC) ground and chassis
Pin 2 — Signal
Pin 3 — Signal
The LD-2 is balanced in and out, and consequently has no hot
(+) pin. Pins 2 and 3 carry the input as a differential signal.
Use standard audio cables with XLR connectors for balanced
signal sources.
Most modern balanced audio sources (electronically balanced
or transformer output) conform to the wiring convention
previously described and interface correctly with the LD-2.
However, an audio source may produce noise if it connects pin
1 to a quiet internal audio ground, and is then connected to
pin 1 of the LD-2 (chassis/earth). To alleviate this noise, try
disconnecting pin 1 (or the cable shield) of the audio source.
To connect an unbalanced audio source to the LD-2, use the
wiring connections shown below:
RCA output
jack
LD-2 input
XLR
-
3
+
The audio input signal should always be applied between pins
2 and 3. Pin 1 is connected to the chassis which also
connects to earth ground through the AC cable. This allows
interference (EMI and ESD) coupled to the shield of the audio
cable to bleed back to earth ground. Therefore, pin 1 is a
noisy ground and audio signals should not be connected to
pin 1.
2
Tip is
positive
terminal
Ring is
negative
terminal
ï
1
ï
Chassis/Earth
terminal
Shield
Connect shield to - terminal (ring)
if the source equipment is floating.
Do not connect the shield if the
source is grounded.
Figure 2 Connecting the LD-2 to an unbalanced source
AC POWER
AC INLET
AND
VOLTAGE SELECT SWITCH
The LD-2 uses an international standard IEC 320 Mains AC
inlet. This convenient rear panel receptacle accepts many
power cord types for mains outlets used throughout the world.
The LD-2 must have the correct power cord for the AC power
in the area in which it will be used.
The audio outputs are muted internally during normal power
on and off, and in case of sudden loss of AC power or
unstable line voltage. This precaution prevents noise
transmission, and possible damage, to interconnected devices.
Voltage select
switch
IEC 320
male power inlet
Do not use a ground-lifting adapter or cut the AC
ground pin.
To avoid electrical shock and damage to the unit,
use the power cord specified by Meyer Sound or an
equivalent that satisfies the requirements of the
local safety testing agency. Do not operate the unit
if the power cables are frayed or broken.
AC FUSE
Figure 3 The LD-2’s dual voltage operation
The LD-2 operates in two AC voltage ranges: 90 - 125V and
180 - 250V, at 50 or 60Hz. The voltage select switch on the
rear panel must be set to the proper voltage before applying
AC power. Connecting the LD-2 to a 225VAC source with the
voltage select switch in the 90 - 125V position could blow the
fuse. Unplug the power cord before changing the voltage
select switch!
5
Always disconnect the power cord before changing the fuse.
To replace the fuse, insert a flat-blade screwdriver in the fuse
cap and gently turn counterclockwise; the fuse springs from
its socket. Replace only with a 5 x 20 mm, T 250 mA, 250 V,
time-lag fuse that conforms to identical safety agency
standards.
If the fuse blows again, contact Meyer Sound for repair
information.
LEFT AND RIGHT CHANNEL FUNCTIONS
Each channel is equipped to control a full range main system.
Each has a Signal/Mute-Clip LED indicator; mute switch; gain
control; Mid-Hi, Mid-Bass or AUX, and Sub output controls;
and a male XLR output connector for each output. The Master
gain control sets the channel's overall level. The Mute switch
mutes the entire channel. The bicolor Signal/Mute-Clip LED
indicates input signal presence and level with a variable
intensity green color, and clipping or mute with red.
switch should be out.
NOTE: Meyer Sound’s self-powered subwoofers are equipped
with internal active processing that provides
carefully derived low and high pass filters. Therefore,
these loudspeakers may be fed with full range
signals directly from the system source or with lowpass filtered signals from Meyer Sound LD-1A or LD2 processors. We do not recommend feeding these
subwoofers with low-pass signals from third-party
external crossovers due to the uncertainty of the
resulting phase response from these filters.
The Mid-Hi, Mid-Bass/Aux and Sub outputs each have a level
control and mute switch. The level control modifies the level
set by the channel's Master gain control; the mute switch
affects the corresponding Mid-Hi, Mid-Bass/Aux, or Sub output
only. For example, the Mid-Hi output could be muted without
affecting the Sub or Mid-Bass/Aux outputs. Additional
functions specific to each output are described in the
following sections.
The Mid-Bass/Aux and Sub outputs each have a polarity switch
(φ and Sub φ, respectively). With the switch out, the polarity
is set to 0ø. Pushing the switch in inverts the polarity 180ø
with respect to the out position.
MID-HI OUTPUT
In applications where only the Mid-Hi and Sub output sections
are used for the main system, the Mid-Bass/AUX sections on
both channels may be used for driving auxiliary systems such
as fill loudspeakers. When mid-high or full range cabinets
(MSL-4, CQ-1/2) are connected to the Mid-Bass or AUX output
as auxiliary systems, a Low Cut filter is provided which rolls
off frequencies below 160Hz (-12dB/octave).
The Mid-Hi output has two switch-activated, optimized filters.
Pushing in the Lo Cut switch activates a high-pass filter (160
Hz, Q = 0.8, -12 dB/octave) that performs a crossover
function for the Mid-Hi output. The filter is bypassed with the
switch out (Figure 4). This filter compensates for the low
frequency rise in the overlap region when MSL-4 and PSW-2
cabinets are arrayed together.
Pushing the Array EQ switch in activates a filter (6 dB cut at
220 Hz, 0.6 octave bandwidth) to equalize the low-mid rise
produced by three to five horizontally arrayed MSL-4s. The
filter is bypassed with the switch out. (Figure 4)
No Low Cut
NOTE: The Array EQ filter compensates for MSL-4 array
characteristics in free-space. We recommend using the
Meyer Sound SIM System II Sound Analyzer1 and CP10 Parametric Equalizer2 to measure and correct
problems caused by the acoustical environment.
Low Cut
In
It is important to note that the Mid-Hi output produces a fullrange signal when both the Array EQ and Lo-Cut filters are out
(bypassed).
MID-BASS/AUX
AND
Array EQ
In
SUB OUTPUTS
The Mid-Bass/Aux & Sub Crossover network, optimized for the
DS-2P or DS-4P and 650-P or PSW-2 is composed of a low-pass
and an elliptical filter. Pushing the switch in activates the
two-way crossover, sending frequencies below 80 Hz to the
Sub output and above 80 Hz to the Mid-Bass/Aux output.
Array EQ and
Low Cut In
With the switch out, a full-range signal is sent to both the
Mid-Bass/Aux and Sub outputs. When a DS-2P or DS-4P is used
alone as a subwoofer, or is not included in the system, the
Figure 4 The LD-2’s Mid-Hi Output Filters
1. The Meyer Sound SIM II is a computer-based dual channel FFT
analysis system optimized for electroacoustic measurement.
2. The CP-10 is a dual-channel, complimentary phase, precision analog
equalizer with five bands of parametric equalization and two bands of
shelving filters.
6
EXAMPLE CONFIGURATIONS
This section demonstrates the flexibility and utility of the LD2 with four sample applications.
larger size does preclude tight-packing configurations with the
MSL-4. The 650-P also lacks rigging hardware.
LOUDSPEAKER PLACEMENT
MSL-4, DS-2P/DS-4P,
AND
POLARITY
The loudspeakers in the following configurations are in a
close-proximity coplanar orientation, unless otherwise stated.
In general practice, placing adjacent loudspeakers more than 5
feet apart may require setting them to opposite polarities to
compensate for the propagation delay between these
loudspeakers.
MEASUREMENT
AND
The MSL-4 is driven from the Mid-Hi output with the Lo Cut
filter switched in for the purpose of minimizing overlap that
would otherwise alter the frequency response when combined
with the DS-2P/4P and 650-P. Invert the polarity of the 650-P
versus that of the MSL-4 and DS-2P/4P.
CORRECTION
Mid-Hi
MSL-4
LD-2
Input Line Driver
Sub
Mid-Bass
650-P
Figure 6 The LD-2 with an MSL-4, DS-2P/4P, and 650-P
PSW-2 FLOWN
WITH
MSL-4; 650-P
ON THE
FLOOR
Positioning subwoofers in a flown cluster (along with the
other loudspeaker components) is preferred by some designers
because in doing so the low and mid-hi frequencies are
produced and aurally localized (perceptually) to a single or
centralized source. The identical dimensions of the PSW-2 and
MSL-4 allow them to be easily flown together. The Mid-Hi
output drives the MSL-4 with the Lo Cut filter in. The Sub and
Mid-Bass outputs drive the 650-Ps and PSW-2s with the MidBass and Sub Crossover switches out, sending a full-range
signal to each loudspeaker and providing independently
adjustable level control.
Figure 5 The LD-2 with an MSL-4 and PSW-2
AND
650-P
Adding the DS-2P or a DS-4P to an MSL-4/650-P system
enhances LF power and clarity. With the Mid-Bass or AUX and
Sub Crossover switches in, the Mid-Bass and Sub outputs are
sent signals optimized for the frequency response capabilities
of the DS-2P/4P and 650-P.
Measurement and correction tools are required to optimize any
professional sound system. This is all the more necessary and
complicated for applications requiring large numbers of
loudspeakers, loudspeakers in complex acoustic spaces (in
which there will be multiple interactions between the
loudspeakers and the architectural/acoustic surfaces) and/or
when multiple loudspeaker positions or zones are required.
We recommend using the Meyer SIM System II Sound
Analyzer and CP-10 Parametric Equalizers to assist in the
process of choosing and configuring loudspeaker positions.
SIM-II is perfectly suited to measure propagation delays
between subsystems, to set the correct polarity and signal
delay, to measure and to equalize the frequency response
resulting from the acoustical environment and the interaction
between loudspeakers. Contact Meyer Sound for assistance
with your application.
MSL-4
AND
PSW-2
The MSL-4 and PSW-2 form a compatible full-range system.
However, due to an overlap in the low frequency range
between the two adjacent loudspeakers there will be increased
acoustic output over the 65-120Hz frequency range when
these loudspeakers are combined. Note that the loudspeakers
are in phase in this region. The combined frequency response
may be optimized by activating the Lo Cut filter on the MidHi output of the LD-2. Ensure that the polarity switches for
the output channels feeding the MSL-4 and PSW-2
loudspeakers are not inverted. In most applications, the ratio
of MSL-4's to PSW-2's is 2:1, but the Sub and Mid-Hi gain
controls in the LD-2 allow for variations in this ratio while
maintaining the spectral balance of the system. The 650-P
may be used interchangeably with the PSW-2 but the 650-P's
Set the MSL-4 and PSW-2 to the same polarity. The polarity of
the 650-P depends on the height and distance of the
measurement position from the subwoofers and flown cluster.
Figure 7 The LD-2 with an MSL-4, PSW-2, and 650-P
7
MSL-4
AND
PSW-2
WITH
CQ DOWN-FILL3
The correct polarity for the 650-P subwoofers is dependent on
the height and distance of the measurement position relative
to the subwoofers and the flown loudspeakers.
This example shows the LD-2 used to integrate a system of
self-powered loudspeakers for a larger venue.
We recommend that the entire system be measured, phasealigned, and equalized using the SIM System II Sound
Analyzer and CP-10 Parametric Equalizer.
LD-2
Mid-Hi
Output
Input
Set the MSL-4 and 650-P to the same polarity; reverse the
polarity of the CQ. The polarity of the 650-P depends on the
distance of the measurement position from the subwoofer and
flown systems.
MSL-4 Mid-Hi
Mid-Bass Aux
Output
Sub
Output
CQ Down-fills
LD-2
Right
PSW-2 Subwoofers
CP-10 EQ
Input
Figure 8 The LD-2 with an MSL-4, PSW-2, and CQ downfill
MSL-4
FLOWN FOR MAINS,
CQ
DOWN FILL, AND
Mid-Hi
Output
Mid-Bass/Aux
Output
Sub
Output
650-P
Figure 9 shows half of the system using the Left channel;
identical connections can be used for the Right channel to
create the other half. The MSL-4 and CQ arrays are flown; the
650-Ps are on the floor.
Delay
MSL-4 Mid-Hi
Left
Mid-Hi
Output
CP-10 EQ
Mid-Bass
Input
Mid-Bass/Aux
Output
The Mid-Hi output drives the MSL-4 flown array. Array EQ
switches should be in, to minimize the additional low-mid
energy from the combined CQ's and MSL-4's. The Lo Cut filter
should be switched out, as there is no significant overlap
between the MSL-4s and the 650-P with this physical
arrangement. The Left channel's Mid-Bass/Aux output controls
the CQ down-fill system. Because the primary section of this
array will have greater acoustic output than that of the downfill system, there will be audible and measurable low
frequency energy from the primary loudspeakers into the
downfill coverage area. To insure that these loudspeakers
combine properly in this intersecting downfill coverage area:
650-P Subwoofers
Figure 9 The LD-2 with an MSL-4, Mid-Bass loudspeakers
(the DS-4P is shown), CQ, and 650-P
DIFFERENTIAL INPUTS
1. 0 dBV = 1 Vrms; 0 dBu = 0.775 Vrms; 0 dBm = 1 mWrms
2. Ratio of maximum sinewave to A-weighted noise floor.
3. Level set to unity gain (0 dB).
4. 0 dBV, 1 kHz sinewave input. Gain at +12 dB main channel,
+6 dB auxiliary channel.
· Invert the polarity to the CQ's in order to align them to the
high frequency output of the MSL-4's and to reduce combining in the low frequency range.
· Use the Mid-Bass/Aux Lo Cut filter to eliminate the LF rise
caused by the overlap in frequency response with the 650-P
· Delay the down-fill to compensate for the propagation
delay between the down-fill and primary loudspeakers in
the intersecting coverage area.
· The Mid-Bass and Sub crossover switch should be out.
3. This arrangement will work with any suitable loudspeaker system,
e.g. DF-4, UPA-1P/2P, etc.
8
LD-2 SPECIFICATIONS
A r c h i t e c t u r e1
Master Left and Right Gain Controls
Mid-Hi, Mid-Bass/Aux, Sub Gain Controls
Low-cut Filter for Mid-High & Mid-Bass/Aux Output
Array EQ Filter for Mid-Hi Output
Mute
Polarity
Audio Inputs
Connector
Type
Impedance
Wiring
RF Filter
Common Mode Rejection Ratio
Signal Presence/clip LED
LED Threshold
LED Full Intensity
Audio Outputs
A C Po w e r
Audio
Pe r f o r m a n c e
GAIN RANGE
GAIN RANGE
Physical
Notes
1 female XLR per channel
Differential balanced input circuit
10 kΩ differential (between pins 2 and 3)
Pin 1: chassis/earth ground; Pin 2: signal; Pin 3: signal
Common Mode: 425 kHz low-pass; Differential Mode: 142 kHz low-pass
> 80 dB (typically 90 dB); measured in the range 50 Hz - 1 kHz
(Variable intensity; monitored at the input for each channel)
-26 dBV (50 mVrms) pink noise or sinewave
-10 dBV (300 mVrms) pink noise or sinewave
Type Balanced, cross-coupled simulated transformer topology
Impedance 10Ω balanced (between pins 2 and 3)
RF Filter Pins 2 and 3 shunted to chassis via 500 pF capacitance
CONNECTORS
CONNECTORS
DRIVE CAPABILITY
DRIVE CAPABILITY
-12 to +6 dB
-12 to +6 dB
160 Hz high-pass, -12 dB/octave, Q = 0.8
6 dB cut at 220 Hz, 0.6 octave bandwidth
Mute switches for Master, Mid-Hi, Mid-Bass or AUX, and Sub outputs
Toggles for Sub and Mid-Bass/Aux outputs
Main 1 female XLR/channel
Wiring Pin 1: chassis/earth ground; Pin 2: signal; Pin 3: signal
Maximum Voltage 1600 Ω Load: +/-22.5 Vpk (+24 dBV, +26.2 dBu sinewave)
No Load: +/-25.0 Vpk (+25 dBV, +27.2 dBu sinewave)
Maximum Current +/-70 mApk (10 Vrms into 200 Ω)
Cables and Load Drives > 100,000 pF (> 1000 ft cable) without instability or distortion
Connector IEC 320 (line, neutral/line, earth)
Operating Voltage 90 - 125 VAC / 180 - 250 VAC (selectable with rear panel switch);
50/60 Hz
Maximum Power 25 Watts; Fuse: 5 x 20 mm, T 250 mA, 250 V, time-lag
Frequency Response
Bandwidth
Phase Response
Dynamic Range2
Noise Floor3
THD + N4
Gain Accuracy
Mute Attenuation
< +/-0.2 dB 20 Hz - 20 kHz
DC to 60 kHz (-3dB)
< +/-3o from pure 3 µsec delay (DC - 20 kHz)
> 120 dB
> -95 dBV A-weighted; > -90 dBV un-weighted
< 0.005% (typically 0.002%)
< +/-0.15 dB at +6 dB gain; < +/-0.25 dB at 0 dB gain
> 80 dB
Each Channel -12 to +6 dB
Auxiliary Channels
Dimensions Height: 1.75” (1 rack space); Width: 16.75”; Depth: 6.96”
Weight 13.5 lb (6.1 kg); shipping: 15 lb (6.8 kg)
Enclosure/Finish Black 16-gauge steel chassis; 1/8” aluminum rack ears
1. 0 dBV = 1Vrms; 0 dBu = 0.775 Vrms; 0dBm = 1 mWrms
2. Ratio of maximum sinewave to A-weighted noise floor
3. Level set to unity gain (0 dB)
4. 0 dBV, 1 kHz sinewave input. Gain at +12 dB main channel
Copyright © 2000 Meyer Sound Laboratories, Inc.
All Rights Reserved
9
LD-2 SIGNAL FLOW DIAGRAM
LED
SIGNAL
& CLIP
DETECTOR
GRN
RED
MUTE SWITCHES
RED
Common mode:
425kHz low-pass
Normal mode:
142kHz low-pass
XLR
80dB CMRR
Laser Trimmed
3
Input
10kΩ
RF & ESD
FILTER
1
Master Mute
Switch
DIFF
AMP
fc
2
Master
Level
Earth and Chassis GND
-12 to +6dB
Audio GND
10Ω on
power supply board
High Current
Full range
Flat
Mid-Hi
Level
Mid-Hi Mute
Switch
XLR
DIFFERENTIAL
DRIVER
Low-cut
ArrayEQ
Full range
2
Mid-Hi
Output
1
High Current
Polarity
normal
XLR
DIFFERENTIAL
DRIVER
Crossover
PWR-ON
PWR-OFF
MUTE
RF
BLOCK
3
2
Polarity
inverted
-12 to +6dB
80Hz
Elliptical
3
Earth and Chassis GND
Mid-Bass
or Aux Mid-Bass
or Aux
Level
Mute Switch
Low-cut
RF
BLOCK
-12 to +6dB
–6dB at
220Hz;
0.6 octave
bandwidth
160Hz
Q=0.8
-12dB/oct
PWR-ON
PWR-OFF
MUTE
Mid-Bass
Output
1
Mid-Bass
or Aux & Sub
Crossover
Earth and Chassis GND
High Current
Sub
Level
Full range
Sub Mute
Switch
Polarity
normal
XLR
DIFFERENTIAL
DRIVER
Crossover
-12 to +6dB
Polarity
inverted
65Hz
Q=0.9
-12dB/oct
PWR-ON
PWR-OFF
MUTE
RF
BLOCK
3
2
Sub
Output
1
Earth and Chassis GND
Both channels of the LD-2 are identical.
10
FRONT AND REAR PANEL DETAIL, PHYSICAL DIMENSIONS
All units in inches
3.45
16.75
19.00
The front of the LD-2, showing rack ears and corresponding space requirements
3.45
16.75
Rear
3.45
6.86
Side
11
CONTACT INFORMATION
Meyer Sound Laboratories, Inc.
2832 San Pablo Avenue
Berkeley, CA 94702
tel: 510.486.1166
fax: 510.486.8356
e-mail: info@meyersound.com
www.meyersound.com
05.088.003.01 Rev A
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