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critical band vocoder
Yes, recent efforts have shifted toward partitioning the spectrum in
We used critical-band divisions to assess frequency resolution in
restricted regions of the spectrum.
Healy & Bacon (2006). Measuring the critical band for speech. JASA,
Also, equal distance along the BM (Greenwood's 1990 formula) can be
considered a good representation of CIs.
Faulkner, Rosen, & Smith (2000, JASA, vol. 108, pp. 1877-1887)
Fu, Chinchilla, & Galvin (2004, JARO, vol. 5, pp. 253-260)
Xu, Thompson & Pfingst (2005, JASA, vol. 117, pp. 3255-3267)
There are other authors that have used these divisions and other
division methods as well.
However, as Shannon and his colleagues showed, vocoded broadband
speech is robust and, so long as analysis (speech) bands match
presentation (noise) bands, performance differences resulting from
different frequency divisions (linear, log [Greenwood], "standard" )
Shannon, Zeng, & Wygonski (1998, JASA, vol. 104, pp. 2467-2476).
Hope this helps,
Date: Wed, 17 May 2006 15:07:02 -0500
From: beaucham <beaucham@xxxxxxxxxxxxxxxxxxxxxx>
Subject: critical band vocoder
For many years vocoders were used for data reduction of speech signals.
A vocoder separates the input signal into consecutive bands, codes the
band outputs, and then transmits the coded information to a receiver
for resynthesis. An early model of Bell Lab's vocoder used 20
uniform-width bands below 3000 Hz and 10 log-spaced bands above 3000
Hz, extending to 7500 Hz.
Recently, mel-frequency cepstral coefficients have been popular for
speech recognition. Mel frequency spacing is approximately proportional
to critical-band frequency spacing. My question is: Has anyone designed
and tested a vocoder using critical-band spacing of the filters?
Univ. of Illinois at Urbana-Champaign
Eric W. Healy, Ph.D.
Department of Communication Sciences and Disorders
Arnold School of Public Health
University of South Carolina
Columbia, SC 29208
(803) 777-1087 voice (803) 777-3081 fax