Building off of Eli Fieldsteel’s FM Synthesis synth, I think it would be useful for the community to code other typical FM Synthesis Algorithms, as seen in the DX7. I’d appreciate any help on this. I’ll attach a pic of the diagrams for the algorithms. And I’ll attach the code for the synthdef of Eli’s FM Synth from his tutorials.

```
//interval space of sidebands = frequency of modulator
//number of audible sidebands = index of modulation = amplitude of modulator
//modulator frequency + carrier frequency = ratio (e.g. 2:1 = 500hz:250hz), then we get harmonic content
//as integers increase for carrier ratio, we get more harmonic sidebands centered on the overtone series, and intervalic spacing stays the same
//non-integers (e.g. 2.1, 2.3, 2.5) for carrier ratio produce inharmonic content that sounds like a bell
//integers used for the modulator ratio, the carrier stays put but the spacing of the sidebands increases, so we get different combinations of specific overtones
//non-integers for modulator ratio produce inharmonic content
//index = modAmp/modHz, loosely corresponds to number of audible sideband pairs in the spectrum
(
SynthDef(\fm, {
arg freq = 500, mRatio = 1, cRatio = 1, index = 1, iScale = 5, amp = 0.2, atk = 0.01, rel = 3, cAtk = 4, cRel = (-4), pan = 0;
var car, mod, env, iEnv;
iEnv = EnvGen.kr(
Env.new(
[index, index * iScale, index],
[atk, rel],
[cAtk, cRel]
)
);
env = EnvGen.kr(
Env.perc(atk, rel, curve: [cAtk, cRel]),
doneAction: 2
);
mod = SinOsc.ar(freq * mRatio, mul: freq * mRatio * iEnv);
car = SinOsc.ar(freq * cRatio + mod) * env * amp;
car = Pan2.ar(car, pan);
Out.ar(0, car);
}).add;
)
Synth(\fm, [\freq, 46.midicps, \rel, 1, \index, 20, \iScale, 0.10, \mRatio, 2.0]);
(
Pbind(
\instrument, \fm,
\freq, Pseq([73.42, 87.31, 130.81, 146.83, 98, 116.54, 174.61, 233.08, 73.42, 87.31, 130.81, 146.83, 98, 116.54, 233.08, 174.61], inf),
\dur, 1/8,
\stretch, 3.5,
\mRatio, 1,
\cRatio, 1,
\index, 1,
\iScale, 5,
\amp, 0.2,
\atk, 0.01,
\rel, 3,
\cAtk, 4,
\cRel, (-4),
\pan, 0,
).play;
)
```