Ambeeka, a hybrid MIDI polysynth and voicecard host.
Ambeeka consists of a compact motherboard serving as a “host” for up to 6 sound synthesis voicecard. While this design is primarily intended to be a flexible hybrid polysynth, it could also be used as a drum module/drum machine.
The motherboard comprises 6 audio outputs, each one connected to a voicecard ; a global mono output ; a pair of MIDI input/output ; a SD card slot ; a 5V/8V/-8V power supply capable of delivering 150mA on the 8V rails and 350mA on the 5V rail ; the master MCU and the user interface elements.
The voicecards (a pair of each being attached to the 3 voicecard ports) are SPI slaves, they receive note and modulation data from the motherboard ; and output monophonic audio, ideally 1V pp. 3 designs of voicecards implementing a refined version of the Shruthi-1 engine are provided.
Each of those use a different filter (4-Pole with LM13700, 4-Pole with SSM2164, 2-Pole SVF with SSM2164).
Original developer: Emilie Gillet.
The firmware is released under a GPL3.0 license. It includes a variant of the formant synthesis algorithm used in Peter Knight’s Cantarino speech synthesizer.
The PCB layouts and schematics, documentation, analyses, simulations and 3D models are released under a Creative Commons cc-by-sa 3.0 license.