(T) Compression On/Off

Can anyone tell me what the compression on/off function on the original head unit menu is for ?

Compression is an audio process which maintains all the different audio levels in the cd your playing at a consistent volume. Means it will bring quiet stuff up a bit and stop the really loud parts of a song blowing your head off...smoothes out the signal

Cheers chris.............thats great to know, now I can stop transfering music tracks sampled at different bitrate to seperate discs !