User manual

Page 26 User manual P1 Audio Processor
THE EXPANDER
Expanders reduce audio gain when the audio level falls below the
expander threshold setting as shown in the diagram below;
The P1 expander is a simple to use with a single knob to set the
threshold.
As the audio input falls below the threshold, its gain is reduced
progressively from 0dB (no gain change) up to a maximum gain
reduction of 20dB (called the expander depth). So loud sounds are
unaffected but quiet sounds get quieter. This is expansion of the
audio’s dynamic range below the expander threshold. The red
ACTIVE LED lights whenever any expansion of the audio signal is
taking place.
The expansion ratio is how much the audio gain is reduced as it falls
below the threshold point. The P1 uses a fixed ratio of around 1:3
(with a soft knee at the threshold point) so that (below the threshold)
for every 1dB that the input level drops, the output level will drop by
3dB.
The P1 expander attack time is approx. 3ms. This is the time it takes
for the expander to go from the full 20dB gain reduction to no gain
reduction as the input audio level rises towards the threshold point.
It’s fast enough so that the front end of a vocal phrase or note is not
lost but slow enough so as not to cause distortion in slowly rising
audio.