RetroBand is 4 band analog distortion.
RetroBand is a distortion unit at heart, it goes from warming, sharpening, roughing up, softening and smoothing - or all these combined. It may desirably enrich sterile sound sources. Failing equipment can be easily simulated and this allows plenty of creativity. With some luck, it makes things sound "larger than life". The transient enhanced IM with mid-side stereo control can change or revive a stereo image, too.
RetroBand models several aspects of the interaction between gain stages and transformers of analogue gear, referred to as intra-modulation (IM), ie. Class A/B gain stage switching distortion. It also features several forms of transient shaping in-between the stages. As opposed to sterile but perfect digital sound, IM is a distortion that can sound good. It happens especially in less than ideal analogue class A/B gain staging, which means it's present in a plenty of vintage gear.