User manual

MAX12 (3.0E)
AMP-L
CUT
GRISP
MUTE
OVL
-12 dB
-6
+6
0
Controls on AMP-L
module
Frequency response of CUT and LFC circuits
LFC switch and indicator
When MAX12 cabinets are used without an active subwoofer
selecting LFC, Low Frequency Compensation, extends the low
frequency response of MAX12 cabinets down to 75 Hz. The yellow
LFC LED illuminates. In active mode only the channel A LFC switch
is functional.
IS/GR indicators
These indicators give a three stage indication of ampMAX signal
levels.
−
Input Signal Present
(green) illuminates when the signal
presented to the controller input exceeds a -36 dBu threshold
value. The ISP circuit is unaffected by the setting of the
controller mute switch and level control.
−
Gain Reduction
(yellow) illuminates when the controller
limiter reduces gain by more than 3 dB.
−
Overload
(red) illuminates when an overload occurs in the
signal path (input signal too high) or when the amplifier gain is
reduced because the output current is too high (e.g. due to a
short circuit).
With active mode selected, the channel A indicators show the state
of the LF channel and the channel B indicators show the state of
the HF channel.
Level controls in passive mode
The CH A and CH B detented level controls adjust the controller in-
put sensitivity and have a 20 dB range, -14 dB to +6 dB, calibrated
in 1 dB steps. The level controls are normally set to 0 dB.
Level controls in 2-way active mode
In active mode the CH A / ACTIVE level control adjusts the
controller input sensitivity and has a 20 dB range, 14 db to
+6 dB, calibrated in 1 dB steps. The CH B/ HF-LEVEL control
adjusts relative HF level in 0.5 dB steps. For a flat response,
whatever the setting of the CH A / ACTIVE level control, the CH B
/ HF-LEVEL control should be set to 0 dB. The more precise 0.5 dB
HF level detent settings invalidate the control scale markings. To
account for the actual 10 dB range of HF level adjustment from
7 dB to +3 dB divide the control scale setting by two to arrive at
the actual value for relative HF level.
Operation with P1200A and AMP-L module
The AMP-L module occupies a single P1200A module slot and
provides a single linear amplifier channel, which drives the pins
1+/1 of the respective output connector. For operation with the
AMP-L module MAX12 cabinets have to be configured for two wire
operation (see section "Four wire and two wire operation").
In passive mode up to two MAX12 loudspeakers can be driven by
each P1200A power amplifier channel. Fitting one AMP-L and one
subwoofer controller module allows a single mainframe to drive
two MAX12 and two active subwoofer cabinets (C7-SUB or
C4-SUB). All cabinets can be linked together locally and fed by a
single four-core cable from either mainframe output connector.