3 ms·

I'd definitely love to hear more about your technique once you're willing to say more about it. I'm really interested in time-frequency representations in gener

by ssfrr 7y ago

I'd definitely love to hear more about your technique once you're willing to say more about it. I'm really interested in time-frequency representations in general. One way to get high frequency resolution from the STFT or Wavelet transform is to use the phase derivative within each frequency band, which is usually called "instantaneous frequency", and is closely-related to the phase-vocoder (different from the daft-punk-famous vocoder). The main issue with this kind of instantaneous phase estimate is that it assumes there's only one dominant frequency within each band - does your method improve on that?

avaku 7y ago
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 :).