Peak Limiter; Compressor Controls - DigiTech VCS1 Owner's Manual

PEAK LIMITER THRESHOLD
The Peak Limiter puts an instantaneous "ceiling" on the transient peak levels of your audio material
without affecting dynamics below the threshold. This feature is essential for digital recording and
speaker protection for live sound. In the furthest clockwise position, the limiter is off. Turning the
control counter-clockwise engages the peak limiter. The LED shows when peak limiting occurs and
the VU meter (in the G.R. switch position) will show the amount of attenuation.
COMPRESSOR THRESHOLD
The compressor threshold control is used to set the minimum level at which you want gain reduction
to occur. Turning this control counter-clockwise from the rightmost +20 dBu position brings the
threshold lower so that more of the program material is compressed. The Green (-) LED shows that
the audio signal is below the threshold and is not being compressed. The Red (+) LED shows that
audio has exceeded the threshold and is being compressed.
Note: The legend around this control are calibrated for the Hard Knee setting. When you
switch to Soft Knee, you should turn this control 10 dB in the clockwise direction to achieve
equivalent gain reduction due to the increased gain of the soft knee detector circuit.
COMPRESSOR RATIO
This control varies the amount of "squeeze" you need for the audio material that exceeds your
threshold setting. Turning the control clockwise from the 1:1 (off) position increases the ratio from
gentle compression (2:1 to 8:1) to hard limiting (>8:1). Compression is expressed as a ratio to show
that, for a specified increase in input level, there will be 1dB increase in output. For example, a ratio
of 10:1 means that for a 10 dB increase in input level, the output will only increase by 1 dB.
ATTACK TIME
The Attack Time control allows you to tailor how fast the compressor acts on audio exceeding the
threshold. Slowing the attack time allows a little of the input transient from a drum or guitar to slip
through before compression sets in. This can preserve punch while keeping levels under control.
Faster attack times tend to cause a more obvious compression effect.
RELEASE TIME
Release Time is the time it takes for the compressed signal to return to its original level once the
input signal is no longer above threshold. The VCS-1 uses a true logarithmic timing circuit called
"TLC" (True Logarithmic Compression) that more closely matches the response curve of human
hearing and results in very natural-sounding dynamic control. This timing curve evokes the "classic"
sound of vintage compressors so popular today. The TLC timing is most transparent at longer
release times but will produce a pleasing effect at short settings as well.
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