The Korg Volca Mix Pack. Inc Volca Mix Beats FM & Bass is the ultimate all-in-one Volca package comprised of four Volca units which you can use independently or all together to create a wide range of sounds and rhythms. The Volca Beats is a compact analog rhythm machine featuring a 16-step sequencer and powerful analog sounds. The Volca FM is a versatile 3-voice polyphonic FM synthesizer also featuring a 16-step sequencer and onboard sound editing capabilities. The Volca Bass is designed to create powerful analog basslines featuring three oscillators and analog filtering. The Volca Mix is a 4-channel mixer which you can use to mix all the Volca units together ideal for live performances and sound experimentation.