Voicing
The String and Synthesizer sections of the 49-note Omni utilized the Mostek MK50240 Top Octave generator IC along with divide-down circuitry; as a result, these sections were fully polyphonic, as opposed to subsequent polyphonic synthesizers such as the Sequential Circuits Prophet-5 and Yamaha CS-80 which featured dynamically allocated, limited polyphony of 5- and 8-voices respectively (although these units featured a far more comprehensive and complex synthesis architecture).
The three sections of the Omni - Strings, Synthesizer, and Bass - were all simultaneously available and mixable; the String and Synthesizer sections featured separate audio outputs on the rear panel of the unit which allowed separate amplification and signal processing of these sections for stereo effects. The Omni was single-oscillator in nature; normally, the String section alone was processed through the on-board, patented ARP 3-voice Chorus Phaser circuit, producing the lush, moving sound the instrument is most known for. However, the Synthesizer section was processed through this circuit when a front panel "Chorus Phaser" switch was activated, simultaneously summing the String and Synthesizer section outputs and slowing the Chorus speed.
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