Korg X-911 for sale. Analog Guitar Synthesizer. This funky little analog synth was designed to be played from a guitar, but you can play it from any suitable audio signal (guitar, flute, and monophonic sine waves are best for tracking purposes) or the right cv and gate compatible synthesizer (hz/volt like the MS-20, MS-10 etc). There are built in preset sounds as well as synthesizer waveforms that can be mixed and the filter sounds very nice. One of the features we like most is that the synth section lets you play different octaves at once for a fat layered sound. Each of these layers has its own adjustable VCA envelope parameter so the resulting layered sound can have components each with somewhat different envelopes.