This is a bold dynamics processor that is capable of compression, expansion, and can intensely color the signal with distortion. The crunch switch activates a tangental clipping limiter which prevents the output from going past 1.0.
To operate with compression, choose a suitable threshold level, and also pick a ratio that equates to less than 1 (i.e. 1:5). To operate as an expander, pick a ratio that equates to more than 1.