Compression Artifiacts; Pumping And Breathing; Clicking Or "Zipper Noise; Reduced Gain Structure - Alesis CLX440 Reference Manual

Compression Artifiacts

When you apply a lot of gain reduction (6dB or more), you may
hear some problems on the output. Here are a few common side
effects to applying a lot of compression and some ways to avoid
them.

Pumping and Breathing

When a compressor is making large changes to the input signal
(10 to 12 dB or more), the noise floor will also rise and fall with
the signal level. When this noise signal rises and falls drastically
between signals, such as a heavily compressed, noisy drum
track, you might hear the noise level "breathing" between drum
hits. One solution to this breathing problem is to turn up the
release time. This way, the noise floor won't have time to rise
between drum hits.
However, if the Release time is too long, lower level signals after
the peak will be lost as the compressor slowly stops reducing
gain. This is called "pumping" as the lower level signals (noise
included) slowly fade back up to their normal signal level. The
secret to avoiding these problems is to achieve a balanced release
time on the input signal.

Clicking or "Zipper Noise"

You may also hear clicking if you are doing a lot of compression
with a very short attack or release time. If this is the case, try
raising the attack or release time to stop the clicking.

Reduced Gain Structure

As you compress the signal more and more, the output level will
be lower as a result. Use the
gain you've lost during compression. By watching the
OUTPUT
the
OUTPUT
match.
CLX-440 Reference Manual
and
GAIN REDUCTION
knob so that the input and output levels roughly
chapter 3 • basics of compression
knob to make up for the
OUTPUT
meters, you should be able to set
,
INPUT
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