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Audio Processing - why Subband? why Octave banks? and why Uniform banks?

Started by Yan.L November 29, 2004
Hi, all

I believe this is a very basic and old question. I know there are a number of 
advantages of subband processing. Here I'd like to ask for your opinions of 
why subband is so widely used in audio signal processing applications, not 
only in audio compression, but on many other audio related topics, e.g BSS, 
surround effects...

Researchers also talked about octave-band filter banks. They, of course,
resemble human auditory system. Anything else? over uniform banks.

Thanks!
"Yan.L" <waters@starhub.net.sg> wrote in message
news:df850db4.0411291420.9ad7310@posting.google.com...
> Hi, all > > I believe this is a very basic and old question. I know there are a number of > advantages of subband processing. Here I'd like to ask for your opinions of > why subband is so widely used in audio signal processing applications, not > only in audio compression, but on many other audio related topics, e.g BSS, > surround effects...
Because our hearing system tend to work that way?
> Researchers also talked about octave-band filter banks. They, of course, > resemble human auditory system. Anything else? over uniform banks.
I think you hit on the main advantage of filter banks that are proportional to frequency rather than fixed frequency in Hz (e.g. octave-based vs. Hz-based). Since the human ear detects frequency/pitch on this logarithmic basis, using this kind of modeling makes sense. For example, a common topic in subband processing is frequency masking. This works on an octave basis, not a Hz basis.