Loudness, Hearing loss, thresholds ... (KEVIN AUSTIN )

Subject: Loudness, Hearing loss, thresholds ...
Date:    Sun, 16 Sep 2001 12:32:29 -0400

I'm sorry that I can't frame this question quite correctly, but any help would be useful. My understanding is that in a 'hearing test' (just for freq response), a series of tones of lower and lower amplitude are played until the subject no longer perceives them (they are below the person's threshhold of hearing). Given an 'A weighted' loudness curve: if at the age of 15, my threshold at 1kHz was 10 dB, and for 100 Hz was 45 dB (standard (?) loudness response, the 10 phon curve); when I am tested at age 50, and my 1 kHz threshold in 20dB, and my 100 Hz threshold is 72 dB; (the curve indicates that the 20 phon threshold should be 52 dB); it would seem to indicate that I have had a 20dB (or 20 phon?) hearing loss at 100Hz, as the normalized loudness curve would indicate that a 20 phon loudness curve should have a 100 Hz threshold of 52 dB. If I am monitoring a 90dB signal (at 1 kHz) will I perceive the 100 Hz signal as being 20 db quieter than it would have been without the hearing loss, or will I perceive it as being 12 dB lower in amplitude (based upon the 70 phon curve). This question arises as I would like to know if (while monitoring a signal at 90dB), I should add 12, or 20 dB of 100Hz boost to 'hear it the way others will'. My instinct says that being psychometric, equalization should be determined by the phon (loudness) curves (but I'm not scientist). Sorry not to be clear, but more and more frequently (younger) students in sound classes are coming in with varying kinds and degrees of hearing loss (notably at 4kHz), and 'equalization' issues come up. Best Kevin kaustin(at)vax2.concordia.ca ------------------------------------------------------------------------- -------------------------------------------------------------- Professor K Austin EuCuE - Department of Music / Departement de musique universite Concordia University 7141, rue Sherbrooke o Montreal, QC H4B 1R6 CANADA -------------------------------------------------------------- tel: (1) 514 - 848 - 4709 FAX: (1) 514 - 848 - 2808 Vous pouvez ecrire en francais ou en anglais.

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