2264ALB Limiter / Compressor
Issue 1
COMPRESS RATIO
Five compression ratios are provided:
•
1.5:1
•
2:1
•
3:1
•
4:1
•
6:1
The characteristic is shaped such that the onset of compression is smooth
and progressive, the true ratio being established within about 6dB above
the threshold point.
The graph below shows the relationships between input and output levels
for each of the five ratios, with
THRESHOLD
set to -20 dBm.
THRESHOLD
The threshold point may be varied in from -20dBm to +10dBm giving a
wide range of effects.
Low ratios operated from a low threshold will preserve the impression of
dynamic range while enabling the operator to achieve a significantly better
signal-to-noise ratio when recording.
A high ratio operated from a high threshold gives a partial limiting action.
GAIN
When a threshold point below line level is chosen, it is necessary to add
gain after compression so as to restore the mean programme level.
The
GAIN
control provides up to 20 dB of additional gain, and gain added
in this way inevitably increases the level of all signals including noise.
Care should therefore be taken in attempting high degrees of
compression, necessitating large increases of gain.
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