Re: Rationale for Critical Bands

[Martin Braun <nombraun@xxxxxxxxx>]

Richard F. Lyon wrote:

> The "critical bandwidth" is a simplification of the concept of a 
> psychophysical "auditory filter", which is a bandpass filter that can be 
> measured with various experiments, such as detection of probe tones in 
> notch-noise maskers.

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.

The concept is a psychological one, and whenever it was not verified by 
physiological data it has turned out to be pretty much worthless.

> Find more in books: 
> http://www.google.com/search?q=%22critical+band%22+%22level+dependence%22&tbs=bks:1

Sorry, this is not a useful link. Or does it mean to put off people from 
finding something?

If there is support for your claims in the literature, please say where. 
Thank you.

Martin


---------------------------------------------------------------------
Martin Braun
Neuroscience of Music
S-671 95 Klässbol
Sweden
email: nombraun@xxxxxxxxx
web site: http://www.neuroscience-of-music.se/index.htm




----- Original Message ----- 
From: "Richard F. Lyon" <DickLyon@xxxxxxx>
To: <AUDITORY@xxxxxxxxxxxxxxx>
Sent: Monday, June 14, 2010 5:42 PM
Subject: Re: Rationale for Critical Bands


> The "critical bandwidth" is a simplification of the concept of a 
> psychophysical "auditory filter", which is a bandpass filter that can be 
> measured with various experiments, such as detection of probe tones in 
> notch-noise maskers.  These measurements can be done at different levels, 
> and show a clear level-dependence of the psychophysical auditory filter 
> and its bandwidth, or critical band, following a pattern consistent with 
> the variation seen in cochlear mechanics.
>
> Some types of experiments reveal a level dependence in the CB, presumably 
> based directly on the cochlear filtering.  Other experiments show a more 
> level-independent CB, and that's what corresponds to the further 
> processing in IC, according to some experimenters.
>
> Find more in books: 
> http://www.google.com/search?q=%22critical+band%22+%22level+dependence%22&tbs=bks:1
>
> Dick
>
>
> At 9:46 AM +0800 6/14/10, Daniel Bowling wrote:
> > Dear List,
> >
> > Has anyone considered why humans exhibit critical bands in 
> > psycho-acoustical experiments (e.g. masking, loudness summation, 
> > detectability of phase changes)? Is the assumption that the origin of 
> > critical bands is in the physiology of the cochlea? If so, how is this 
> > justified? If critical bands result from overlap/interference of 
> > vibrations on the basilar membrane one would expect their bandwidths to 
> > change significantly at different sound pressure levels (because more 
> > auditory nerve afferents over longer portions of the cochlea are activated 
> > by higher SPLs, and fewer afferents within restricted areas of the cochlea 
> > are activated by lower SPLs), but this does not seem to be the case.
> >
> > In vision, attempts to rationalize psychophysical phenomena in terms of 
> > retinal physiology have had very limited success.
> >
> > Any thoughts would be much appreciated.
> >
> > Thanks,
> >
> > Dan