The 'tight' switch alters the ratio of the compressor from 2.5:1 to
6:1. When engaged the compressor will squash the signal more and give
it less of a dynamic range than when switched out. For heavier compression press this button in.
The 'punch' switch
alters the attack time of the compressor. When switched out the attack
time is fast and the compressor will reduce the gain of a signal almost
immediately after the level passes the threshold. When pressed in the
attack time is lengthened so that the compressor does not reduce the
gain of the signal until after the initial transient, therefore
preserving the initial punch of a sound.