Today's Lesson

Compressors and limiters are very similar. Both compressors and limiters reduce the volume of a signal passing through them, but the goal is different. A limiter is used to reduce the volume of a sound until a specified threshold, so that it doesn’t clip, whereas the goal of a compressor is just to reduce the dynamic range or the loudest and quietest parts of a signal.

The primary difference between a compressor and limiter is the ratio used in reducing gain. In a limiter, this ratio is set up to be as close to infinity:1 as possible, meaning, (no matter how much the input signal changes, the output level will remain pretty much the same).

Ratios above 10:1 are considered hard limiting.

Every output on QSC’s TouchMix 8/16 and 30 includes a limiter. The 4 main controls (threshold, ratio, attack and release) function the same as a compressor. For a quick review on these controls, see Sound Advice | Compression Explained.

In live sound application, limiters are most often used to prevent overload in a signal chain. For example, setting a maximum volume level to protect users of in-ear monitors, or protecting loudspeakers and amplifiers from clipping.

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