Adjusting Input Gain - AMX Modula Instruction Manual

Digital Gain (Volume) Output Boards
Output volume can be adjusted using either a control panel that supports this feature (see the control
panel's instruction manual or quick start guide) or BCS (Basic Control Structure) commands from an
external controller.
BCS Volume Adjustment
Volume can be adjusted using one of three BCS command methods: Absolute, Relative, or Increment/
Decrement. Directions for adjusting volume using the Absolute Method (adjusting volume to a specific
decibel level) are given below. Information and instructions for the other two methods can be found in
the Instruction Manual – BCS Basic Control Structure Protocol on the AMX AutoPatch CD or at
www.amx.com.
To adjust volume using the BCS Absolute Method:
1. Enter the Volume Absolute command using the format below. Replace the "#"s with the level
number and the output number, and replace "^^^" with the decibel level. Enter the decibel level as
a decimal number to the tenth place without the decimal point (e.g., –31.5 dB is entered as -315).
CL#O#VA^^^T
Example
Adjust the volume to +10 dB for Output 3 on Level 0 (VM 0) by entering the following BCS command
line:
CL0O3VA100T

Adjusting Input Gain

For stereo audio boards that support input gain, adjustments (within the gain range for the specific audio
inputs) are normally made during system setup; however, they can be made at any time during normal
operation. When audio is adjusted for a device, the adjustment applies to all levels switching audio
signals. Stereo input boards are set to unity gain at the factory.
Caution: We strongly recommend that input gain adjustment be made only by a qualified installer or
dealer.
Purpose and Uses of Input Gain
Adjusting input gain (the nominal level of the signal from the source device) allows source signals of
varying amplitudes to be equalized before they are routed and the volume is adjusted. Equalizing source
levels provides a consistent reference for volume adjustments and eliminates jumps when routing a new
input to an output. Input gain adjustment is also used for equalizing amplitudes between balanced and
unbalanced inputs.
To equalize input levels by adjusting input gain:
1.
Route the first input (source) to an output (destination).
2.
Adjust the input gain for the source to the desired dB level (see page 102).
3.
Repeat for all inputs that will be routed to the same output.
Note: The total through-system gain (the amount of input gain plus the amount of output gain)
specified for any input to output routing path cannot exceed 10 dBr. If a volume command is entered
that exceeds 10 dBr when it is combined with the gain of an input, the command will be accepted
(and will be indicated in status results) but will not result in an audible difference of more than 10 dBr.
Modula Instruction Manual
Stereo Audio Boards
101