[PD] suggestions for spectral "weight" anaylsis

Eran Sachs eransachs at hotmail.com
Fri Jan 3 13:03:00 CET 2014

Hello João,Take a look at example 06 in William;s tID, which does timbral ordering of small grains quite similar to what you are describing. I was really happy with what I got, but I had a vaguer idea in mind... William, is there a way to choose certain "descriptors" for the reordering? Or to give different "weight" to certain parameters?
Happy 2014, list!Zax


To: william.brent at gmail.com
Date: Fri, 3 Jan 2014 11:30:17 +0100
From: jmmmpais at googlemail.com
CC: pd-list at iem.at
Subject: Re: [PD] suggestions for spectral "weight" anaylsis

Hi William and all,
I thought there would some relevant things in your library. I'll look into your suggestions later.
I don't have a patch that other people can look at, but I can try to explain the context a bit better:- I have a sound of ~40s spoken voice. I'm going to split it in fragments (for now 100ms each) and reorder them  - one of the possibilities of reordering the fragments would be to have a "continuous" timbre change in the end. E.g. going from noisy consonants to clean vowels- for the analysis, I guess a mixture of pitch and harmonicity (don't know yet in which order it should be done) would be adequate
I noticed your objects work in real time. As the analysis is to be done before the performance, I guess I'll either let the sound play throughout to get the analysis data, or then I'll divide the fragments through x analysis patches, to make it run x times faster.
In this case it is spoken voice, but I guess it could by anything else.
Hi João,
A measure that would give something near 1.0 for white noise and near 0 for a sine wave would be "spectral flatness", which is in the timbreID library. But if you're looking to see how well a spectrum's partials line up harmonically, you won't find that in timbreID yet. One quick option would be to use sigmund~ to get the current pitch, then search the spectrum for the amount of energy in bin ranges related to the expected set of harmonics. Compare that with energy in non-harmonic bins. But then, for things like gongs that sound "pitchy" but have inharmonic spectra, that won't be much help. Depends a lot on what you're trying to do.

You *might* find specSpread~ useful, which measures how widely or tightly energy is concentrated around the spectrum's center of gravity. It's in units of Hz though.

On Thu, Jan 2, 2014 at 12:38 PM, João Pais <jmmmpais at googlemail.com> wrote:


I wanted to ask if there are any suggestions for spectral "weight" analysis.

With "weight" I mean a factor which would measure the harmonicity of a sound - e.g. white noise being 1, and a sinus/silence 0. Surely it exists a propper word for this already, but I don't know one.

Is there any external or patch around that does something similar?




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William Brent

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Conflations: conversational idiom for the 21st century


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