Chameleon Labs 7720 - Manual (Page 3)

3
Front Panel Controls and Indicators
Power:
This switch turns power on and off. Power on is indicated by a blue LED.
Comp:
This switch allows the user to hear the processed signal or the unprocessed signal
with the flip of a switch. When the switch is in the upper position the red LED is
illuminated, indicting that the unit is in the circuit.
Meter:
The
illuminated meter displays either channels gain or the stereo audio signal
compression in dB.
Meter switch:
The meter switch allows the meter to indicate either channels input level, either
channels output level or the amount of stereo audio signal compression.
Sidechain:
This section modifies the control of the compressor with a mono audio signal
introduced through the sidechain XLR input. To use the sidechain circuit, the
sidechain switch is put into the upper position. This will illuminate the blue LED
giving the user a visual indication that the circuit is active and that the sidechain
audio is in control of the compressor, not the left and right audio inputs.
HPF:
The high pass filter (HPF) rotary control allows the sidechain or main audio signal
to be equalized to minimize lower frequency audio signals' effect on the
compression character of the unit. The HPF affects the detection circuit, not the
actual audio. The selector has six settings. The first setting does not introduce any
filtration into the sidechain circuit. The next five settings are 60 Hz, 90 Hz, 130 Hz,
200 Hz and 440 Hz. These selections allow a wide variety of choices. The high pass
filter is designed so that the frequency selected is 3 dB down, with a roll-off of 12
dB per octave.
Threshold:
This rotary pot control is used to adjust the audio level point at which the
compressor begins working. The range is from -20 dB to +20 dB.
Attack:
This six position, switched control is used to adjust the attack time of the
compressor, or how fast it will react to a signal that exceeds the threshold level. The
six settings are 0.1milliseconds, 0.3 millisecond, 1 millisecond, 3 milliseconds, 10
milliseconds and 30 milliseconds.