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.