Formants and speech perception

Eric Smith erc at cinenet.net
Thu Dec 7 03:56:22 EST 1995


In article <199512050358.WAA59619 at acs.bu.edu>,  <simonson at ACS.BU.EDU> wrote:
>first is the most recent literature on signal processing for cochlear
>implants (see Sandlin's book on digitally programmble hearing aids, 
>published by Allyn & Bacon for a good summary of this research).  The
>results seem to be better speech understanding when the signal is 
>NOT digitally processed by features (formants), but rather, when the
>frequency spectrum is maintained.  


The important difference may be that the formants weren't processed
accurately enough.  In particular, noise caused a lot of errors.  Now,
with the spectrum maintained, those errors are no longer a problem, and
there is enough redundancy in the speech signal to make it intelligible
in a lot more noise.  But that doesn't mean formant processing is
necessarily worse than spectrum preservation.  Only that the formant
processing has to be done better, and that spectrum preservation works
better in the meantime, because it lets the brain do the formant
processing.  But another advantage of spectrum preservation is that it
reproduces environmental sounds better.  Speech is far from being the
only thing deaf people want to hear.




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