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Re: hearing aid question: "boominess"

On Mon, 2 May 2005, Richard H. wrote:
BTW This is a generic problem - not just "own voice" ... other peoples
voices too. I have tried other non-NAL1 algorithms and other more
advanced models ... all to no effect, so I might try fitting the other
[similar] ear instead in case something "deeper" is happening on the
current side.

I presume that you are fitting a single digital aid (ie unilateral, we are talking UK here ;-) ).

 In which case it introduces a delay between microphone and loudspeaker of
about 6-7 msec.  Judging by the moderate flat loss, I presume that you are
not fitting one of the ultra-low delay open-ear hearing aids.

(a) the flat 40 hearing loss group tend to be the most critical of delay
(measured primarily 'own-voice', see Stone & Moore, Tolerable Hearing Aid
delays IV, Ear & Hearing, April 2005).  Across subjects there is a range of
sensitivity to effects of delay: you may have one of the more 'sensitive'.

(b) if it is a unilateral fit, then what is the loss in the other ear ?
One of the subjects in Marriage et al., (IJA vol 43:198-210, 2004)
"Comparison of three procedures for initial fitting of compression hearing
aids......." had a symmetric hearing loss but volunteered for a unilateral
fit.  He could not play table tennis with the aid inserted because of the
conflicts in delay across both ears when he hit the ball (aside from the
proprioceptive component of the strike).  The aid he was using had a delay
of about 6 msec.

Michael Stone PhD, Psychoacoustics Group Department of Experimental Psychology University of Cambridge, Downing St. Cambridge CB2 3EB.

Group site:  http://hearing.psychol.cam.ac.uk/
Dept site :  http://www.psychol.cam.ac.uk/