Ratio – The ratio of the incoming signal to compressed signal when compression is 
active. E.g. when set to 3:1 and when compressing, every 3dB increase in level at 
the input will result in only a 1dB increase of level at the output. 
Threshold – Adjust the input level at which compression will be active. 
Gain – Use to compensate for the resulting attenuation of the signal. 
In/Out – Enable or disable the compressor.