I’m new here - and don’t know if the rules prohibit me from sharing stuff … I couldn’t find anything in the TOC prohibiting this type of post so here goes!
I recently released a new desktop synth based on the Yamaha YM2413 chip. It is a generative sequencer (with full MIDI implementation for sequencing other gear) with a 9 voice polyphonic 2-Op FM synth. It’s based on the Teensy 4.0 and uses an old-school (but purple) 20x4 character display.
The design plays on a limitation of the YM2413 in that it is only capable of using one custom instrument at a time. The three generative sequencers onboard can be set to different instruments, causing the chip to produce tones in strange in between places - hence the “CONJUNCTIONS”. Think of it as voice “smudging” not voice “stealing.” The name (and color of the synth) is inspired by the film “The Dark Crystal”.
All synth parameters of the YM2413 are accessible and the synth itself can be setup to be used as a sound module with 9 voices of polyphony.
Cases and button caps are 3D printed. I’ll be posting the STLs on my site. Firmware is closed source right now but could open up in the future after some much needed commenting.
The scale of production is manageable for my one-person business. Printing the cases is probably the biggest hangup … but my new printers are roughly 4x as fast (I’ve just upgraded my two 3D printers from Ender 3 S1s to Bambu A1 minis).
Plenty of tutorials and example videos on youtube.
It took me about a year and a half of development/experimenting (mostly troubleshooting the analog out from the YM2413) and I’m happy to answer any questions about the process.
Nice work! I like the concept of a small generative synth. Also the ability to send the sequencing to external gear is great. I would purchase this. Have you thought of offering a DIY kit?
I have thought about a kit. With the way the PCB is constructed currently, it would only require soldering the Teensy and the headers on the LCD. I’d need to write up and photograph the build guide and such.
Haha, I don’t know what the new ones are like but the originals were so simple that their existence was more confusing than anything they did! They were pretty much just little music boxes that played various preset sound loops which you could cycle through, almost like later noise generators that people use to help them sleep or whatever.
You can definitely do a lot more with this, just something about the form factor and meditative vibe brought them to mind
I’ve had an hour or three with mine, highly recommended. I love polyrhythms and I love dirty old FM. When I get back home to it my next thing is to play with midi to start working out how to get chord changes among the timbre and rhythm changes.
I’m not sure I understand the musical purpose of each of the three tracks having their own separately chosen scale and root note but the thinking of the creator might become clear with more time playing, and it might just be “because flexibility”! Truly great tho.
I must check if it’s already possible but one thing I’d quite like with incoming midi is bottom note transposes track 1, middle does tr2, highest note transposes tr3. That’ll make it a polyrhythmic wersi-casiomatic gritty fm accompaniment box…
You could set each sequencer to a different MIDI channel and send each sequencer one note of the chord you want to play. If you set the scale of each sequencer to “mon” they will only play the root note (note being sent via MIDI to each channel).
Alternately, you could also set a sequencer to chord mode, and it will generate random chords given a sequencers root note and scale settings.
Each track has independent root and scale for flexibility. Some sounds are not tonal, but can sound good in a clashing, percussive way when set to conflicting roots and scales.
Wow, what a great little synth. I really like the tones you get out of it and the intuitive way you can get there… just a pity that postage and customs fees over to the UK make it a little unachievable for me. Best of luck with it!
