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Re: Rationale for Critical Bands

Ok, I'm a bit puzzled here.

First, an auditory filter description, level dependent and overload sensitive though it is, does carry considerably more information along with it than the Bark Scale.

Second, ditto for auditory filter description vs. ERB's.

Now, I'm wondering what "confusion" you refer to, frankly.  While it's application, rather than research, I am personally aware of several very common applications that use the idea of critical bands/ERB's, and ones that work quite well by using this "confusion" you refer to, in particular MPEG-1, especially Layer 3, oh, say, both Psychoacoustic models, but in particular Psychoacoustic Model 2.  MPEG-2 AAC. AC3. DTS-HD and relatives. WMA and relatives.

Just to name a few.

Those of us, like me, who use such results understand that there is more going on, but that the basic concept of place vs. frequency is valid, and what was long ago described as an 'excitation pattern' will carry a substantial amount of information regarding what can and what cannot be detected in a given auditory stimulus.  Obviously, there are a variety of other issues, which are handled in various fashions.

Psychoacoustic models for codecs are interesting in quite some fashions, in that the time response at high levels must be handled at the same time as narrower frequency response at lower levels. The user, after all, has a "volume" (let's leave the market and lay confusion between loudness and intensity for another time, ok?) control, and can change the rules on you at will. You have to understand this when designing your codec.

So, the real world has shown, absolutely conclusively, that the simplification to auditory filterbank has a very strong, clear application. I think most, if not all, who use it are quite aware of the simplification. (Although BLMD did have to be beat into a few folks' crania, I must admit.)



James D. Johnston  (jj@xxxxxxx)

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-----Original Message-----
From: AUDITORY - Research in Auditory Perception [mailto:AUDITORY@xxxxxxxxxxxxxxx] On Behalf Of Martin Braun
Sent: Monday, June 14, 2010 10:25 AM
To: AUDITORY@xxxxxxxxxxxxxxx
Subject: Re: [AUDITORY] Rationale for Critical Bands

There is no difference between the concepts of the "auditory filter" and the 
"critical bandwidth", let alone in simplicity. Both are extremely 
oversimplified and loose, and thus have been causing unending confusion.


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