a question on FM

teeshirtguy5's icon

Are there any FM boffins in here?

it's not strictly a max question but if i wanted to emulate a HPF then an LPF with FM how might i do it?

Im after a sound that starts sort of as noise then becomes a hpf saw sweeping down to a full saw then reducing the partials to just a few at the bottom, like a LPF

If there was a way of also adding a prominent 7th note without playing it in that would be a bonus

thanks

brendan mccloskey's icon

Hi
Not an FM boffin myself (though they do appear here: https://cycling74.com/forums/carrier-and-harmonicity-in-fm-synthesis). And the following remarks are subjective, as I don't have Max in front of me to test/verify; so, "noise" of a sort in FM can be quickly achieved (in a 2-op algorithm) with a high and irrational mod ratio (31.73 for example) if your carrier is low (< 100Hz), and a ridiculous mod index (> 80, eg). Self-modulating modulators are easily driven into noise too, with less extreme settings. To generate a saw, you want to sweep down to a lower and more rational mod ratio and a sensible index (

HTH
Brendan

brendan mccloskey's icon

And a seventh is just an octave 2:1, take away a second 9:8 (I think) . . .

brendan mccloskey's icon

I threw this together in PD, should give you a starting point (todo: how to ramp from irrational to rational, high to low floats, and also add a seventh)

c74-fm.png
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teeshirtguy5's icon

Brendan thank you!

totally missed these replies, this is great, thanks!