Document, in the form of MAME drivers1, the digital and digital-analog internals of classic music machines. The focus is on digitally-controlled analog synthesizers and early digital devices.
Classic analog synthesizers, such as those of the 80s, are widely recognized and respected for their sound. Their audio circuitry has been studied for decades, and a lot of information about that can be found online. However, people often don't realize that many "analog" synthesizers are built around bespoke digital computers.
This effort aims to document the digital side of the story, and expose how the digital and analog work togeter. It aspires to cover this oft-neglected part of computing and music history, in the hopes that people find it educational.
Current focus: misc cleanup and improvements
Status of other work:
| System | Digital | Digital-analog interface | Interactive layout | Full DC | Audio |
|---|---|---|---|---|---|
| Moog Source | Yes | Extensive | Yes | Minimal | No |
| Moog Memorymoog | Yes | Partial | No | No | No |
| Paia MIDI2CV8 | Yes | Yes | Yes | Yes | N/A |
| Paia Fatman | Yes | Yes | Yes | Minimal | No |
| Oberheim Xpander | Extensive | Partial | Minimal | No | No |
| Oberheim OB8 | Minimal | Minimal | No | No | No |
| Oberheim DMX (early version) | Yes | Yes | Yes | Yes | Yes |
| Linn LinnDrum | Yes | Extensive | Yes | Yes | Extensive |
| Alesis MIDIverb / MIDIFEX | Yes | N/A | Yes | N/A | Yes |
| Roland TR-707 / TR-727 | Yes | Extensive | Yes | Yes | Yes |
| Sequential Six-Trak | Yes | Yes | Yes | Yes | Yes |
| Sequential Prophet 5 | Yes | Extensive | Yes | Yes | Yes |
Legend:
- Digital: Documentation state of the computer(s) used to to control the synth (UI, voice control). Does not include DSPs.
- Digital-analog interface: Documentation state of the analog circuitry that interacts with the Digital portion in some way. For example: LFOs and EGs whose state is accessed by the firmware, analog inputs and outputs, cessette I/O, autotune circuitry, etc.
- Interactive layout: A functional MAME layout.
- Full DC: Documentation of all audio control voltages and currents in the synthesizer, even those not read by the firmware.
- Audio: Documentation state of the audio circuitry.
Footnotes
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These MAME drivers cannot replace the real thing, nor the myriad of commercial and free alternatives for these machines. For starters, most of us can't run these emulations, since we don't have access to the firwmare. And even if we could, important functionality (such as audio!) will be missing or lacking. The work described here is a documentation of hisotrical facts. If you are interested in computer music history, or want to take a glimpse at how these instruments worked, stick around and have a look at the driver source code. If you are looking to make music, these drivers are not for you. ↩