The Poly Vocal Source Oscillator is a special dual-oscillator module optimized for use with the Rackmode Vocoder module, but it can independently be used as a standard 1V/oct audio oscillator. What separates it from standard analog-style synth oscillators is its unique "glottal" waveform, which includes specialized parameters that enable it to reproduce both tonal and "air" sounds of the human vocal tract. Other than its polyphonic pitch and gate CV input jacks and multi-voice capabilities, it's functionally identical to the standard Vocal Source Oscillator module.