Korg Volca FM Digital Synthesizer With Sequencer - UsedKorg's Volca FM synthesizer is a compact and easily operated synthesizer module based off of the DX7 FM synth. With an onboard sequencer, six operators, and thirty two algorithms, the Volca FM is a versatile module with plenty of expressive sounds and great features. Use the onboard chorus effect to add some extra flourish to your synth tones or sequences, use one of the nine arpeggiators to get some motion in the mix, or take it on the road with