The core algo is basically like a vocoder (I think), tracking certain frequencies, and as others pointed out might be very very similar to https://en.m.wikipedi

The core algo is basically like a vocoder (I think), tracking certain frequencies, and as others pointed out might be very very similar to https://en.m.wikipedia.org/wiki/Constant-Q_transform https://en.m.wikipedia.org/wiki/Constant-Q_transform (I guess another question is how to implement this effectively in "real-time"). About the question of "assuming there is only one frequency within each band" -- yes, it's a problem, and that's what's causing the "frequency leakage" that you see in the app with the "high-precision: off" (and FFT). To solve this, I've added some extra math on top, which is available via "high-precision: on" in the app. I will release more details when I open source the algo. Please subscribe to email list if you want to receive an update, I am not super active on social media otherwise :).