Spectral Blurring in MSP w/PVOC?

Jul 26, 2013 at 8:22pm

Spectral Blurring in MSP w/PVOC?

I’m looking for a way to implement spectral blurring in real-time in Max. The caveat being that I need to only use MSP objects so this means no Jitter work ala Jean-Francois Charles’ work on spectral processing (http://cycling74.com/toolbox/charles-spectral-tutorials/).
I have read the Phase Vocoder tutorial
(http://cycling74.com/2006/11/02/the-phase-vocoder-%E2%80%93-part-i/)
in order to try and figure it out but have hit a brick wall in my understanding.

My limited understanding of this effect comes from Trevor Wishart and Michael Norris.

http://www.digital-music-archives.com/webdb2/application/Application.php?fwServerClass=ProductDetail&ProductCode=BKE0001#spectralmanipulation

http://www.michaelnorris.info/soundmagic/effects/SpectralBlurring.html

Any insights or examples would be much appreciated!

#257281
Jul 27, 2013 at 1:56pm

From Wishart:

We may average the spectral data in a each frequency-band channel over N time-windows (spectral blurring) thus reducing the amount of detail available for reconstructing the signal. This can be used to “wash out” the detail in a segmented signal and works especially effectively on spikey crackly signals (those with brief, bright peaks). We can do this and also reduce the number of partials (spectral trace & blur) and we may do either of these things in a time-variable manner so that the details of a sequence gradually become blurred or gradually emerge as distinct. (Sound example 3.25).

You can do something like this via the vectral~ object. (the smearing via envelope following) Vectral~ is a vector-based envelope follower and has several different modes.

Looking at the Michael Norris page, it looks like he’s doing something more like sampling a spectral frame every n frames, then interpolating between that and the next one. The part of the implementation that’s not clear is what you do in terms of overlapping frames.

#257320

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