Hey all, recently i started trying to learn how to do FM synthesis in Pure Data. The first example I came across using the +~ operator made perfect sense to me. Here's the patch:

However, when I change the +~ operator to the *~ operator, it still sounds like FM synthesis. And moving the modulation frequency and amplitude even sounds like it's doing what they're supposed to. The main difference is that moving the carrier frequency seems to also act like the modulation amplitude. So my question is, in this second example. How are these operators working differently? Why do they both sound like FM instead of the *~ one sounding like AM?

Thanks !

@Cam Because they're both FM! All that's different is you're changing how the modulating oscillator is scaled. The modulating oscillator is the one on the top; the one on the bottom is the carrier.

Check out Boran Robert's tutorial on basic synthesis methods, there's an example of AM there.

@Cam Its always easier when you can see what the result is....... patch.zip
David.

@jameslo @whale-av Thank you! I figured out they were both FM, except in the second one the carrier frequency is actually another modulation amplitude, and the real carrier frequency is 0hz. At least I'm pretty sure that's what it is. And thanks for the visual representation, although when I plug this into dac~ it sounds likes two oscillators just on top of each other.