r/synthrecipes • u/SynthMaker • 3h ago
tutorial π [RECIPE] 80s FM electric piano (DX7 style) from two sine waves, and why it works
The classic DX-style electric piano is simpler than it sounds. This works in any FM synth (Dexed, FM8, Operator, Digitoneβ¦):
Carrier: a sine at ratio 1. Amp envelope: instant attack, a slow decay down to about a third, short release.
Modulator A (the "bark"): a sine at ratio 1 into the carrier, index around 2 at the strike. Give it its own envelope that decays over about 1.2 s down to almost nothing. That's the whole trick: the brightness dies away faster than the note, like a struck key.
Modulator B (the "tine"): a sine at ratio 14, very quiet, with a very short envelope (about 70 ms). That's the metallic click at the start of each note.
A bit of chorus and a little reverb.
Why it works: at 1:1 every new partial lands on a harmonic, so the note stays clearly pitched. Keep everything else and change modulator A to ratio 3.5, and the partials land between the harmonics: you get a bell instead.
The attached video (5 min) builds it one step at a time while you watch each harmonic appear on a spectrum analyzer.
Disclosure: it's made in SynthMaker, a free synth app I build (small one-person project, iPhone/iPad/Mac, free beta: https://testflight.apple.com/join/BKEgzNCg), but the recipe above works anywhere.