BSS Audio OPAL Series DPR-522 Owner's Manual - Manual (Page 23)

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In operation, the DPR-522 can be considered as an automatic on-off switch
that is placed into the program signal line, the actual operation of the switch
being controlled by the loudness level of the signal. The simplest way to
understand the basic operation is to connect one gate channel into a program
source and operate the controls whilst listening to their effect.
Having connected the input and output leads according to the instructions in
section 5 continue as follows:
1 Make sure that all push-buttons are out, in the non-illuminated position.
2 Set the ‘KEY FILTER’ control to 1KHz, and the WIDTH control to 8 oct.
3 Set THRESHOLD control to out, the RANGE control to 80dB, and the
ATTACK, HOLD, RELEASE controls about centrally on their scale.
4 With the unit still in bypass mode (Channel button out) adjust the external
equipment to give an adequate volume level, and then operate the CHANNEL
switch. The signal should then be cut-off, and there will be no meter display.
5 Now gradually rotate the THRESHOLD control anticlockwise, and observe
that the KEY LEVEL meter starts to indicate the peaks of the program. As soon
as the display exceeds the partially illuminated TH marker on the meter, the
program signal will be passed through to the output as the gate has now
‘opened’ notice too that the green OPEN LED has come on. Spend a few
minutes adjusting the threshold control and watching the display.
6 Now adjust the RANGE control whilst listening to the program. The scale
calibration indicates the attenuation of the signal when the gate is closed.
This means that, rather than being simply on or off, the gate can be set to be
slightly attenuated, or somewhere in between. Turning the control fully
clockwise makes the gate closed level equal to the gate open level, and so it
will appear that the gate is open at all times. The normal setting for this
control will depend very much on the specific application, however for
general noise reduction on background microphone clutter, a range of 20-40
dB will be a good starting point.
7 The ATTACK, HOLD and RELEASE controls can be intuitively operated. The
ATTACK is the time taken for the gate to open once the threshold has been
reached. The HOLD is the time the gate will remain fully open once the
program signal has fallen below threshold. The RELEASE is the time taken for
the gate to fully close once the hold cycle has finished. Take some time to
experiment with these controls to hear their effects on the envelope of the
program signal. Whilst doing this also observe how the gate OPEN and SHUT
LEDs fade between each other, precisely following the sound. You will notice
that these follow the actual times set by the ATTACK, HOLD and RELEASE
controls and is a true indication dynamically of the state of the gate, whereas
the KEY LEVEL meter has dynamics set to give a good indication of program
level.
This covers the basic operation of the DPR-522. For a more detailed
description of the controls, please refer to sections 6.1 thru 6.19. For
information covering specific configurations, please see section 8.0.