A six-voice polyphonic synthesizer that is built around the Raspberry Pi comes from R-MONO Lab, which says in its about section that is a recreational club that consists of the fellow workers of a company that can be found in Hanamatsu, Japan.
The club makes a bunch of things ranging from electronic tools, applications, plastic models and accessories. R-MONO Lab previously exhibited cool musical devices like its Hybrid recorder pipe organ and turntable MIDI controller. For now, the focus will be on its Innovative Raspberry Pi 'S³-6R' synthesizer, which is a six-voice phase modulation synthesizer that yields high resolution (24-bit and 96 kHz) audio.
This build, which is generated on a Raspberry Pi 3 is pretty intricate but can provide incredible sounds. The main features of the build include an Original-Uniq Phase Control and Phase Modulation Synthesis (αα-Phase Modulation), envelope generator and LFO dedicated for phase modulation, 5-Polyphonic when using Super Oscillators. According to Hackaday, R-MONO Lab's S³-6R uses the small MIDI keyboard Roland K-25m, serving as a "dock" for recirculated Roland synths like Jupiter and Juno.
R-MONO Lab has provided audio demos available through SoundCloud in downloadable WAV files. It should be noted that as of now, the group does not have any real plans to release it as products or to publish the source codes.
Raspberry Pi Foundation recently updated the Compute Module with a faster ARM processor. Just January of this year, it announced the new Compute Module 3 (CM3) pleasing Internet of things (IoT) device enthusiasts with a powerful new option for embedded compute abilities costing only at $30. The new board is made to facilitate manufacturers in producing some pretty high quality hardware while being cost effective at the same time. There is a standard version and a lite version of the Compute Module 3.