> > again, Evan, what i would like to hear from you is, given your offered > algorithm for spectral centroid, if you play, say a piano into it, one note > at a time, does C# have a 6% greater spectral centroid or 12% higher than > C? or less than 6%?
It seems to me, with the sqrt in the latest version of the sample code, it will be 6% higher as you'd like. But with more than one frequency present, the weighting is a little funny -- if we're looking at a sum of two sines with equal amplitude at 100Hz and 200Hz, I think this technique will give you a "spectral centroid" of sqrt((100^2 + 200^2)/2), roughly 158Hz instead of the 150Hz you might want. I like your idea of unpinking first, I think that will push the result in this scenario back to 150Hz. Riffing on this idea, if we wanted to make it one step more perceptually correct, we might try combining this unpinking filter with a filter that aproximates the inverse of an equal loudness contour. I'd expect adding some energy at 4kHz to do a heck of a lot more to my brightness perception than adding the same amount of energy at 60Hz or 15kHz. -Ethan On Thu, Feb 18, 2016 at 3:08 PM, robert bristow-johnson < r...@audioimagination.com> wrote: > > > ---------------------------- Original Message ---------------------------- > Subject: Re: [music-dsp] Cheap spectral centroid recipe > From: "Evan Balster" <e...@imitone.com> > Date: Thu, February 18, 2016 1:55 pm > To: music-dsp@music.columbia.edu > -------------------------------------------------------------------------- > > > Anyway, that's why -- in spite of my extensive research in pitch tracking > > -- I don't touch perception modeling with a ten-foot pole. > > > > that's sorta a self-contradiction. > > > > "pitch" is a perceptual attribute of a tone or sound. > > "fundamental frequency" is a physical attribute. > > > > "loudness" is a perceptual attribute. > > "amplitude" is a physical attribute. > > > > "brightness" is a perceptual attribute. > > "spectral centroid" (however it's mathematically defined) is a physical > attribute. > > > > again, Evan, what i would like to hear from you is, given your offered > algorithm for spectral centroid, if you play, say a piano into it, one note > at a time, does C# have a 6% greater spectral centroid or 12% higher than > C? or less than 6%? > > > > also, Evan, i would be very interested in hearing (or reading) what you > might be willing to tell us about pitch detection or pitch tracking. i > realize you may be keeping this trade secret, but to the extent that you're > willing to openly discuss even principles, if not algorithms, i would pay > close attention. (and i am not terribly stingy about knowledge assets.) > > > > > -- > > > > > > > > > r b-j r...@audioimagination.com > > > "Imagination is more important than knowledge." > > > > > _______________________________________________ > dupswapdrop: music-dsp mailing list > music-dsp@music.columbia.edu > https://lists.columbia.edu/mailman/listinfo/music-dsp >
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