IBIS is an analog equalizer that boldly takes equalization to a new level of musicality. Each of its four bands features switch-selectable frequencies centered on and covering musical-step intervals from 32-Hz "C" to 22.35-kHz "F." Its four overlapping bands are labeled with note names and frequency allowing for the first time a "translation" between musician-speak and engineer-jargon. The bandwidth control has similar notation with adjustment from 0.2 octave to 4 octaves per band and a boost / cut range of 12 dB.

The low-cut filter is switch selectable from 20-Hz to 150-Hz with slopes of either 12-dB or 24-dB per octave. Like most Crane Song products, IBIS utilizes discrete class-A circuitry and features a truly unique and adjustable "color" function that can be applied to either the entire audio path or to any individual frequency band. A fully stepped mastering version is also available.