ART Pro Audio Pro Channel - Mic Preamp/Compressor/EQ - Manual (Page 13)

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Attack Switch
The Attack switch selects the attack characteristics of both the tube and optical
compressor circuits. The Fast position (in) allows the compressor to react quickly to
fast-rising attacks. Note that the tube circuit has an inherently fast response and can be
aggressive on signals with quick transients, such as snare drums. The Slow position
(out) can be helpful in reducing compression artifacts for signals with very little high
frequency content, such as piano or flute.
Release Switch
The Release switch selects the release characteristics of the compressor circuit. The Fast
position (in) allows the compressor to recover quickly once the signal falls below the
threshold. The Auto position (out) allows the compressor to adjust itself depending on
the characteristics of the input signal. Use the Fast setting when the signal has repetitive,
consistent characteristics, such as on kick drums, snares, and vocals. Use the Auto
setting when the signal has varying characteristics, such as long decaying notes
alternating with quick notes and mix material.
Type Switch
This switch covers one of the more unique features of the Pro Channel. In the Optical
position (out), the Pro Channel’s compressor employs A R T’s award-winning
Vactrol®-based compression element from the Pro VLA. Switching to the “in” position
engages the dual-triode, tube control element. This circuit is capable of considerably
faster attack and release times than its optical counterpart. Experiment with the two
types of compression to become familiar with how they react to different source
material.
Comp Bypass Switch
A Bypass switch is included on the compressor circuit to enable you to remove it from
the signal chain. In its Norm position (out), the compressor is active. When set to its
Bypass position (in), signal passes from the preamp circuitry to the equalizer without
compression and the adjacent red LED lights. Also, the Gain Reduction LED array
operates as usual, though at a much dimmer level, to remind you that the compressor is
out of the signal path.
Use the Comp Bypass switch to achieve unity gain at the output of the Compressor.
Unity gain is achieved when the compressor’s active level is the same as its bypassed
level. Toggle the switch between Norm and Bypass while adjusting the Compressor
Output level. Once the levels are the same (use your ears and the VU Output Level
meter), you’ve reached the compressor’s unity setting.
Compressor Output Control
The Compressor Output control sets the output level from the compressor circuit.
Typically, a compressor’s Output control is used to add gain to compensate for the
amount lost due to compression.
When the control is fully counter-clockwise, the output is off. Turning the control