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SuperVP bandfilter and processing

OM-SuperVP
#1

Hallo, everyone!

I have some questions and problems about OM-SuperVP.
(patch in attachment)

I used the supervp-bandfilter to “split” a sound to many bands.
The bandwidth of each band is a 1/8 tone=25 Midicent (so in lower register just 0.5-2 hertz).

The original sound (photo1/a.aif) has a relative full spectrum.
But what it has generated is a little bit strange. In this case I got 400+ files. Most of them in lower register have a absolute silence (photo2). And several bands (for example the 012.aiff, the band between 46.249302 and 46.922013 hertz) have sound, but the bandwidth is obviously too wide to 0.6727104 hertz (phote3 photo4 012.aiff).

I want to know what is the problems and how could I get the sounds with a right bandwidth.

Thank you very much!

best regards
Jialin

#2

Dear Jialin,

The problem is neither OM nor supervp, but the size of your bands, which is much too small in the low register. To compute the minimum size of a band, read http://support.ircam.fr/docs/AudioSculpt/3.0/co/FFT%20Size.html.
Since the FFT is linearly, and not logarithmically distributed, the minimum musical intervals in the low registers will always be larger than the musical intervals in higher registers.
You should, probably, introduce a rule that automatically sets the band size to the minimum allowed value.

Good work!

Marco

#3

Dear Marco,

Thanks for your suggestion!

After reading and testing, I built a little machine to calculate the proper Window Size and FFT size value, which depends on the values of bandwidth. It works much better and began to get right files.

All the best!

Jialin

#4

Thank you Jialin for the patch
unfortunately there is a sub-patch missing: Save-text

#5

Hello Vitasok. Thank you for the testing!
Here is the revised version of two patches. You can drag the omp files into the workspace and I think it will work better.
This sub-patch “Save-text” save the returned value into a text-file (In this case: a lot of pathnames/addresses of the generated sound-files).
See attachment::

band-spilter-and-text-saver.zip (200 KB)