Goom is an ambitious DIY MIDI synthesizer module, based on a low-cost microcontroller.
It’s a virtual analog synth that offers 16-voice polyphony and it is fully multitimbral. According to the developer, the total cost of the basic components to make a fully-working synthesizer is just a couple of pounds; the bulk of the cost is in the (optional) knobs and switches panel interface.
Here’s and audio demo track, recorded in a single take from Goom’s analog output. No effects were added:
- Sixteen-voice polyphonic synthesizer
- Fully multitimbral (different patch on each MIDI channel)
- Analogue front panel patch set-up for MIDI channel 1
- Patch set-up using MIDI control change messages for channels 2 to 16
- Two oscillators per voice: sine, sawtooth, square, pulse and intermediate waveforms
- Oscillators can be mixed or combined using frequency modulation or frequency modulation plus feedback
- Three envelope generators per voice (one ADSR and one AD for amplitude, one ADSR for filter)
- Low-pass filter for each voice with resonance control
- Velocity scaling on amplitude and filter cutoff
- Stereo output with pan and volume control for each patch
- 24-bit digital-to-analogue converter
Details on Goom, including circuit design and firmware, are available.