Madsen Aurical and SPL Audiometery

dybala at utdallas.edu dybala at utdallas.edu
Wed Mar 20 19:18:26 EST 1996


CTB1954 (ctb1954 at aol.com) wrote:

> >I read with great interest the recent article in Hearing Jounal about
> >the Loudness scaling procedure and the SPL audiometery feature of the
> >Aurcial.

It sounds like the SPL feature would be useful in 
fitting with the Desired Sensation Level method.

In order to use it you have to convert the HL thresholds to SPL
and then the target values are computed based on the amount of speech 
spectrum that it not being heard.

  > George and Bionet.Audiology:

> I have had my Madsen Aurical for three months.  My main use of the
> Audiometery module has been in HL (headphones) and not SPL (inserts). 
> However, the minimal use of the loudness scaling has been interesting but
> not directly applicable to the instruments I am currently dispensing.  I

It seems that the loudness scaling module would be useful for
most types of compression limiting and wide dynamic range compression
circuits (Kamp etc) that are widely availiable.

Robert Martin in his nuts and bolts article talked about using
sets of real ear curves  at 55 dB (that should sound soft),
65-70 dB (that should be comfortable eg NAL) and at 80-85 dB (that 
should be loud but tolerable eg under UCL)

If you used the loudness scaling function in SPL on the Aurical
you could translate those values directly to the REAR for real
ear verification of nonlinear instruments.

Using real ear to coupler differences you could translate the
targets to 2cc values to help pick the matrix and compression
characteristics for the aid.

The IHAFF has a similar protocol that could be implemented.


BTW George,  I think it was you that said you had info on Fig6.
I noticed that Etymotic is "giving away" the software at AAA
to help fit Kamps!  

Is the program any good or what??



-- 
Thank you for your support,
Paul Dybala
dybala at utdallas.edu
http://wwwpub.utdallas.edu/~dybala/kelly.htm



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