ART Pro Audio TCS - Twin Compressor System - Manual (Page 9)

ART TCS Twin Compressor System
OPERATION
Compression Basics – Compression is an effective way to gently control
the dynamics of a signal. The most important setting in your compressor is
the threshold. The threshold sets the average signal level, above which
the TCS acts on. From there the ratio control sets how aggressively the
compressor holds signals above the threshold to the operating level.
Typically a good starting ratio of 2:1 is suggested for vocal settings, 4:1 for
instruments, and
∞:1 for limiting or sustain. Settings with extremely high
ratios are called limiters because they limit the signal to the operating level.
The attack and release controls are intended for controlling how quickly the
compressor begins (attack) and ends (release) its amplitude reduction. If
your sound seems to lack punch try increasing the attack, and if too much of
the peaks are coming through, decrease it. With release you want to
increase the release time if you hear the compressor pumping, and you
want to decrease it if it seems to lack sustain or dynamics.
Expansion Basics – Expanders are basically the opposite of compressors
such that they increase the dynamic range of a signal. Typically these are
used to remove unwanted portions of a signal that are quieter than the
working material. When there are gaps in the working material, the
expander quiets signals beneath the noise reduction threshold to remove
any unwanted sound and to increase lower level dynamics. An extreme
variant of an expander is a gate, which mutes signals beneath the noise
reduction threshold.
Opto Basics – Optical compression is based on an optical – electric
package made up of (in it’s simplest definition) a light bulb and a photocell.
Many classical compressors employed the use of opto-isolators, and it was
a key element to their “sound”. A properly designed opto based compressor
is more musical that most VCA based designs. The opto-isolator acts on
signal changes much like the eye reacts to light changes – smooth. Based
on these characteristics it is felt optical compression works quite well in
tracking situations
.
VCA Basics – Solid-state compressors make use of what is called a VCA
(Voltage Controlled Amplifier). Sometimes in critical situations an opto
compressor isn’t enough for compression needs, and a VCA based one
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