kind of tutorial: Making a sawtooth bass on a 4 op FM synth

[Aroused by JarJar]

There's a point where it "is" a theoretical sawtooth

is it? I think it reaches noise before it gets the full brightness/the higher harmonics of a sawtooth

That's correct. In FM8 about as close as you can get is 42 feedback on the modulator, 33 from the modulator into the carriers:



Any more modulation and you start to lose the sawtooth shape:



Any more feedback and you add noise:

You wouldn't say that the first picture looks and sounds like a bandlimited sawtooth?

That "noise" you're getting is aliasing, (edit- hmmm, this is with feedback so maybe not, don't know) with a better synth for testing you get a hell of a lot more sidebands (and some funky sci-fi waveshapes on the way) before it gets aliasing "noise".

But I don't know what would happen in a theoretically ideal situation, that would actually have to be done with a spreadsheet or whatever.

Anyway the point is, yes you do have a "bandlimited saw" at a certain point, and even more importantly you can easily demonstrate and use the three basic families of subtractive synthesis waveforms and their (family) connection to C:M ratios, and go from there. The family difference between saws and pulses are the ordered and predictable presence or absence of specific harmonic partials, surely you can see how making these connections makes programming phase modulation synths easier.

[koolkeys]

Oh, I so wish that I fully understood FM synthesis. I can do synthesis in most other forms. But FM, that's my problem. I have FM8 and usually take presets and tweak them, sometimes randomly. But I won't say that I can look at an FM synth with a sound in mind and actually make it very well.

Brent

[foosnark]

You wouldn't say that the first picture looks and sounds like a bandlimited sawtooth?

Close enough for government work, I suppose.

I honestly don't spend a lot of time looking at oscilloscopes. To my mind a "real" sawtooth is that ideal one you can draw with straight lines.

I use my ears and whatever I happen to think sounds good (aliasing, noise, intermodulation distortion and all). I don't think I'd use a plain sawtooth for anything. But I did find it interesting to play with making something saw-ish out of a couple of FM operators.

[Audio Gnostic]

And for petes sake Audio Gnostic, could you please start spell checking?

who teh fuk is pete yo, i aint fucken gonna do shit for pete, that mothafucke aint neva do nothin for me

[Acid Mitch]

And for petes sake Audio Gnostic, could you please start spell checking?

who teh fuk is pete yo, i aint fucken gonna do shit for pete, that mothafucke aint neva do nothin for me

Well you should do it for everyone else that has to read your posts.

[Muzik 4 Machines]

5 years later i still use that same saw wave live (fed in the mfc42 8 pole filter) and it's still sounds badass in big PA's, not AS bright as a pure saw, but more bottom end too, so perfect for a bass line, and 8 of them stacked is pretty huge

(thread digging via image googling Muzik 4 Machines lol)