Operating Instructions
Meyer Sound Laboratories, Inc.
2832 San Pablo Avenue
Berkeley, CA 94702
M-1A
Control
Electronics
Unit
Meyer Sound Laboratories, Inc.
2832 San Pablo Avenue
Berkeley, CA 94702
Operating Instructions
M-1A
Control
Electronics
Unit
Verifying Limiter
Operation
To verify limiter operation in the field:
■
Disconnect loudspeakers, leaving the
amplifier and the M-1A in their standard
connection configuration.
■
If your amplifier requires a load, use re-
sistive loads sufficient to dissipate the full
power of the amplifier.
■
Turn on both the M-1A and the amplifier.
■
Set the VHF switch to CAL, the Lo Cut out
and the Safe switch in.
■
Supply an input to the M-1A, preferably a
sine wave oscillator. If you do not have an
oscillator, use a compact disc with dense
program material and a mixer to produce a
line level signal.
If you are using an oscillator, set the fre-
quency according to this table:
LF limiter HF limiter VHF limiter
200 Hz 5,000 Hz 16,000 Hz
Bring up the input level until you see the cor-
responding limit indicator come on. Since in
each case the indicator will light only if the
limiter actually operates, it provides a positive
indication that the limiter is functioning.
Balancing Amplifier
Gain
The standard connection configuration for the
M-1A Control Electronics Unit uses a single
two-channel amplifier as a bi-amplifier, one
channel for the lows and one for the highs.
In large systems where a number of M-1As
are used, some users prefer to assign one or
more amplifiers only to the lows, and other
amplifiers only to the highs. In either case the
Lo and Hi amplifiers must have equal voltage
gain. To balance your system, you will need
an oscillator and an RMS-reading voltmeter.
■
Connect the M-1A and amplifiers as you
wish to use them, leaving speakers discon-
nected.
■
If an amplifier requires a load, use an
8 ohm resistor sufficient to dissipate the
full power of the amplifier.
■
Input the oscillator to the M-1A and set its
frequency to 1600 Hz ± 5 Hz (use a fre-
quency counter if you have one).
■
Set the M-1A Lo Cut switch out, the VHF
switch to CAL, and the Safe switch out.
■
Measuring with the voltmeter at the Hi
amplifier output, advance the M-1A Level
control to a convenient reading (a few
volts).
■
Now measure at the Lo amplifier output. If
the level is different, adjust the input level
control of whichever amplifier is higher
in output until the Hi and Lo outputs are
equal.
The amplifier gains are now calibrated.
Using the Sub Input
The Meyer Sound B-2EX Control Electronics
Unit does not incorporate a Hi output, and
is designed to be connected in parallel with
the input of the full-range CEU that it is sup-
plementing. If you are using a B-2EX CEU,
do
not
use the M-1A Sub input. Instead,
connect the system input signal to both the
M-1A Input and the B-2EX Input. For further
information, consult the
B-2EX Operating
The M-1A
Sub
input is designed for use with
the Meyer Sound B-2, B-2A and B-2AEX
subwoofer Control Electronics Units.
If you are using one of these CEUs to control
a subwoofer system that is augmenting the
M-1A system, you have the option of con-
necting the subwoofer controller’s Hi output
to the M-1A Sub input. For details, refer to
the
Operating Instructions
for the subwoofer
CEU.
