23-12-2016, 07:02 PM
They're all similar devices - where they differ is in the controls offered, and the extremity of their effects. At their most basic, think about auto-record level in a basic cassette recorder.
As well as compressors, you can get expanders and gates. Similar signal path (VCA, plus a controlling "sidechain"), but the operation is different. Limiters tend to be less sympathetic in action - they are just clippers in most cases. In an FM transmitter, it's there to stop over-deviation, but sounds horrible if you hit it - so the preceding Optimod is set to up to ensure that the signal nearly reaches the clipper, but not quite.
A compressor is used to raise the average level of an audio signal. Makes an instrument sound "fuller", or whatever. And can be used to smooth out variations in level - particularly important for vocals as it's hard to sing at a constant volume. You'd use a gate on loud instruments like drums, or for a mic stuck in front of a guitar amp (so you don't get the hum and buzz in-between notes).
As well as compressors, you can get expanders and gates. Similar signal path (VCA, plus a controlling "sidechain"), but the operation is different. Limiters tend to be less sympathetic in action - they are just clippers in most cases. In an FM transmitter, it's there to stop over-deviation, but sounds horrible if you hit it - so the preceding Optimod is set to up to ensure that the signal nearly reaches the clipper, but not quite.
A compressor is used to raise the average level of an audio signal. Makes an instrument sound "fuller", or whatever. And can be used to smooth out variations in level - particularly important for vocals as it's hard to sing at a constant volume. You'd use a gate on loud instruments like drums, or for a mic stuck in front of a guitar amp (so you don't get the hum and buzz in-between notes).
