superbonbon
Member
I've built a four operator FM synth using the teensy (great fun!), and experienced some unexpected behavior: Even when I set the mod depth of an operator to 0, I get some modulation of phase or frequency. I thought this was a bug with my code, until I looked at the audio library today and found this:
github.com
Apparently for both PM and FM the modulated waveform sets a lower bound on the mod depth of 30 degrees / 0.1 octaves. I'd like to be able to get 0 modulation or very slight modulation (think virtual analog drifting oscillators with only a few cents of frequency modulation). I'm confident that I can just make a local fork of the audio library and change these lower bounds to be 0 degrees / 0 octaves, but this begs two questions:
1) I assume the audio library sets these lower bounds at 30 degrees / 0.1 octaves for a reason - what is it?
2) I'm wary of unintended consequences of changing the bounds to 0 / 0. Are there downstream effects I'm not considering? Maybe some sort of underflow on the mod depth?
I'd appreciate any insight from folks here.
Audio/synth_waveform.h at bd7de878a802841857a762e855e55fcc9da37fa2 · PaulStoffregen/Audio
Teensy Audio Library. Contribute to PaulStoffregen/Audio development by creating an account on GitHub.
github.com
Apparently for both PM and FM the modulated waveform sets a lower bound on the mod depth of 30 degrees / 0.1 octaves. I'd like to be able to get 0 modulation or very slight modulation (think virtual analog drifting oscillators with only a few cents of frequency modulation). I'm confident that I can just make a local fork of the audio library and change these lower bounds to be 0 degrees / 0 octaves, but this begs two questions:
1) I assume the audio library sets these lower bounds at 30 degrees / 0.1 octaves for a reason - what is it?
2) I'm wary of unintended consequences of changing the bounds to 0 / 0. Are there downstream effects I'm not considering? Maybe some sort of underflow on the mod depth?
I'd appreciate any insight from folks here.