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Re: comodulation release of masking (CMR)

> Re: Models of CMR
> One model that has been used to successfully simulate comodulation masking
> release based upon processing of the "raw waveforms" is the modulation
> filter bank model of Dau and colleagues.  Verhey and Dau presented this
> work at a recent ASA meeting (1996; JASA 100, 2625A).
> Dave
> David A. Eddins
> Department of Speech and Hearing Sciences
> Indiana University

Dear list,

A very interesting aspect of the study by Verhey and Dau is that it shows that
one can account for the classic Hall et al. data (1986, JASA 79, 781-787)
without having to assume any across-channel processing. Detection
in their model is based only on (within-channel) changes in the
modulation spectrum.

The data in Hall et al. (1986) were obtained with a masking noise, varying
in bandwidth, which was co-modulated by multiplying it with a single
low-pass noise modulator.

A different class of CMR experiments uses two separate bands of noise as maskers
with identical envelopes but different center frequencies with the signal centered
in one of the bands.
One can present one band in the left ear and the other in the right
ear and still obtain a masking release. This indicates that
across-frequency comparisons/processing are essential in this
sort of experiments because the stimulus components can
in no way interact with each other in a single auditory

I think there is no consensus about the processing of CMR
stimuli although we recently argued that the envelope cross correlation
(not to mistake with the envelope cross covariance or correlation
coefficient) may be helpful in accounting for CMR data
(van de Par and Kohlrausch, 1998a/b: JASA 103 pp 3605-3620; 1573-1579).
In the paper on page 3605 we even describe a model that accounts
for CMR data.


Steven van de Par
IPO-Center for research on user-system interaction
Den Dolech 2
5612 AZ Eindhoven
The Netherlands

Phone: +31 40 2475215
Fax:   +31 40 2431930
E-mail: par@ipo.tue.nl

> On Thu, 1 Oct 1998, Jont Allen wrote:
> > Dear List,
> >
> > Has anybody done a computer simulation of CMR that can accurately
> > simulate results from real experiments. I mean, starting from the
> > time wave forms, compute the envelopes, and then estimate the
> > detection threshold?
> >
> > If not, what is the present `state of the art' of CMR models?
> >
> > Thanks,
> > Jont
> > --
> > Jont B. Allen, Room E161
> > AT&T Labs-Research
> > Shannon Laboratory
> > 180 Park Ave.
> > Florham Park NJ 07932-0971
> > 973/360-8545voice, x7111fax
> > http://www.research.att.com/info/jba
> >

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