This 14HP module is a re-imagining of the ARP 1013 octave filter bank that was announced in 1970 by Tonus as part of the 2500 Synthesizer, but it never made it into production. It consists of eight band pass filters with their cutoff frequency spaced one octave apart, from 63Hz to 8kHz.

The filter is very useful for creating formant and vowel sounds. The individual outputs enable voltage control of the filter by using eight external VCA's - for example the 1032 Mixer & Distributor module.