Compressors & limiters have a lot in common, but also have big differences & are used in different situations.

The biggest difference comes down to the threshold.

On a compressor, the threshold determines the level the gain reduction will begin. When you set the threshold, any time your audio signal passes that threshold, the compressor will react & reduce the gain of the signal.

A limiter won't let the sound get any louder than the set threshold. This is how you can turn up the overall gain & avoid clipping & distorting. If you set the threshold to -1.00dB, the limiter will not allow the sound to go past -1.00dB no matter what you put into the limiter. This can cause things to be squashed, so be careful pumping too much into a limiter.

The ratio also has some differences between the two as well.
A compressor has a low ratio that turns down SOME of the volumes when it goes above the threshold. A limiter has a huge ratio that turns down ALL of the volumes that goes above the threshold.


When to use the two:
Compressor - is great to use when you're trying to control the dynamics of a track. A limiter would be too powerful for this situation & would squash the sound. Compressors can also be used to tame transients or "glue" the sound of tracks summed together.


Limiter - is great to use on a mix bus or master channel when you're trying to turn up the overall gain of a track without distorting it. A compressor would not be idea for this because the makeup gain could cause clipping & distortion to the overall track.