FRESH

Hacker News

Show HN: Resonate – Low-latency, high-resolution spectral analysis

44 points by arjf

by RossBencina

1 subcomments

Nice. To the folks saying "nothing to see here" this appears to be a variation of filter-bank spectral analysis where each band varies in frequency to track "the" in-band sinusoid. Somewhat like a bank of PLLs each with its own tracking bandpass filter. By using IIR filters rather than FFTs you avoid the latency of buffering up a full frame of data before you can run the FFT analysis. I am curious how this handles input containing broadband transients. It might be interesting to use CIC filters rather than an IIR lowpass to get better time selectivity, but maybe that's already been addressed, I didn't read the papers.

by j-river

1 subcomments

A useful demo for this kind of tool would be a side-by-side on difficult inputs: fast pitch bends, dense chords, and low-SNR recordings. Latency is easy to appreciate visually, but robustness under messy audio is what usually decides whether spectral tools become part of a workflow. Even a small set of repeatable test clips would make the tradeoff much clearer.

by _def

1 subcomments

Slowed down higher pitch example was nice to hear, as this is where often conventional methods are heavily artifacted

by deckar01

1 subcomments

I don’t like the bins drifting from so far away so slowly. There needs to be repulsive force that prevents the bins from colliding.
It would be interesting if the resonators could adaptively model timbre to factor out harmonics while still handling unique timbre at each frequency. That could produce a pitch diagram color coded by instrument.
Edit: I bet you could fork a resonator and run over the window it just finished in reverse to correct the drift.

by jmpman

1 subcomments

There are some piano tuners I've found who are a bit on the spectrum, who believe they can tune a piano in a way that no digital device can replicate. I'm skeptical, and would like to see how this method holds up against one of these savants.

by bialamusic

0 subcomment

And this is a tuner using same algorithm: https://apps.apple.com/us/app/resonance-chromatic-tuner/id16...
Also very old stuff :)

0 subcomment

by bialamusic

2 subcomments

I have such app for more than 4 years. Your algorithm is not new - it is new for you only :) Here is the app: https://play.google.com/store/apps/details?id=com.bialamusic...
https://apps.apple.com/us/app/chord-detector/id1495811175