Carl Martin Compressor Limiter Pedal Features and sonic clarity generally found only in studio compressors. Threshold: Working anti clockwise, determines how much of the signal will be compressed. This is also dependent on how much signal is fed from the instrument. Comp: Working clockwise, determines how much compression is applied to the signal allowed by the threshold setting. Resp: Working clockwise, determines the attack/release times, going from slow to fast. In general, if you want to hear the compressor working with a crisp attack you should use slow times. If you require just a silent limiting you should use fast times. Gain: Working clockwise, sets the overall gain. Busy: Indicates the amount of compression being applied, even in bypass mode. The brighter it gets, the more compression is being applied.