AMX BCS Instruction Manual download pdf (Page 19)

Adjusting and Verifying Audio

Instruction Manual – BCS Basic Control Structure Protocol

Adjusting Digital Input Gain

For BCS purposes, adjustments to input signals are referred to as digital gain adjustments, while similar

adjustments to output signals are referred to as volume adjustments. Not all systems with audio support

digital input gain adjustments. Although digital input gain is normally set during installation, if your

system supports digital input gain control, gain adjustments can be made at any time during normal

operation. Digital input gain range is -10 dB to +10 dB. Inputs cannot be muted.

Digital input gain should be adjusted as part of system setup. If adjusting input gain, we recommend

doing so before making any output adjustments.

Caution: We strongly recommend that input gain adjustments be made only by a qualified installer

or dealer.

The purpose of controlling the input gain (the nominal level of the signal from the source device) is to

allow source signals of various 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.

Typical uses for input gain include switching consumer and professional grade audio equipment (whose

levels can vary noticeably) in the same routing system. Input gain adjustment is also used for equalizing

amplitudes between balanced and unbalanced inputs.

Note: The total through-system gain (the amount of input gain plus the amount of output gain) for

any input to output routing path is automatically limited by the matrix switcher. (For the value of

through-system gain and other audio specifications, see your matrix switcher’s instruction manual.)

If a volume command is entered that exceeds the matrix switcher’s specifications, the command will

be accepted (and will be indicated in status results) but will not result in an audible difference if the

dB value entered is outside of the matrix switcher’s audio range.

The following section describes three methods used to adjust digital input gain as part of the process of

equalizing input levels. We recommend routing an input before adjusting its gain; although not

necessary, it can be helpful to hear the adjustment.

To adjust digital input gain use any of the following three methods:

Absolute – adjusts input gain to a specific decibel value

Relative – adjusts input gain by a specific decibel amount

Increment/Decrement – adjusts input gain up or down a step

Important: If the level is not specified in a BCS command, the command is executed on the default

level (normally Level 0), which is defined in the configuration file. If the level is omitted and the BCS

command executes on an unexpected level, check the default level in the configuration file

(for systems without a configuration file, check the product documentation).

To adjust inputs to equalize source levels:

Route an input (source) to the first output (destination).

2. Adjust the digital input gain for the input to the desired dB level by using one of the three methods

on the following two pages.

3. Repeat Steps 1 and 2 for additional inputs that will be routed to the same output.

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AMX BCS Instruction Manual Page 19