6 / 13
4. Control / Connections
4.1. Front
1. Gain
The Gain control adjusts incoming signal level to the VCA circuit. It is always active, so
switching out the limiter function has no effect on this control. This control should normally be
left at ‘0’ to achieve accurate threshold calibration.
2. Treshold
The threshold control has a range of -40 to +22dB, allowing applications from low level
compression to high level limiting. The threshold control determines the audio level above
which gain reduction occurs. When the signal peaks exceed the selected threshold, the LED
comes on and gain reduction is occurring,
3. Ratio
This control determines the ratio of the change in output level to changes in input level for
signals above threshold. The numbers printed around the ration control are calibrated in dB
and indicate the increase input (above threshold) required to produce a 1dB increase in
output. This can be expressed conveniently as a ratio. If the output remains constant no
matter how high the input level, we have an infinite (
∞
) input/output ratio. It should be
remembered that the ratio control has no effect on signals which are below threshold.
4. Attack Time
The response of the compressor/limiter to signal levels above threshold is further defined by
the attack time control. Attack time is the amount of time that the unit takes to attenuate the
output level after threshold has been reached. This unit provides continuously variable attack
times from 200 µs und 20 ms.
5. Release Time
Release time, is the time required to restore system gain to normal after the input signal has
fallen below threshold level. Proper release time will depend on the type of program material
being processed and the way in which the limiter is being used.
6. Output Level
Output level control is provided to fully cut or restore up to 18dB of system gain. For unity
gain, set the control to 0.
