Loud enough??

Subject: Loud enough??
From: KEVIN AUSTIN (KAUSTIN@vax2.concordia.ca)
Date: Thu Feb 25 1999 - 05:13:58 EST


A repost from AUDITORY on LOUD sounds.




>Date: Wed, 24 Feb 1999 16:50:32 GMT
>From: Neil Todd <TODD@FS4.PSY.MAN.AC.UK>
>Subject: loud sounds again

>Dear List
>Thanks for all replies to my request, for your interest attached below.

>Armed with my B&K 2260 Investigator this intrepid explorer set out
>to sample some of Manchester's sounds. To my surprise most venues
>have been extremely helpful and willing for me to take measurements.
>It seems that I can get into just about any place free of charge.
>Damm good thing that I took some precautions though, as recommened.

>For example, in one venue which had PA with a power rating of a mean
>20,000 W(!), I measured on one occasion an LAeq (equivalent continuous
>level, A-weighting) of 111 dB. The peak of power was at 400 Hz (1/3 octave)
>126 dB A weighting, fast response. (This would be about 130 dB on the C
>weighting). At 111 dB OSHA gives the maximum allowable exposure per 8 hour
>day at at 26 minutes. ISO recommend 3.25 minutes maximum allowable exposure
>per 40 hour week!

>The predominance of low frequencies, 500 Hz and less,
>apparently the source of pleasure that loud dance music provides via
>vibrotactile and other non-auditory sensations, is consistent with damage
>to low frequency hearing (as well as high frequencies) that I have been
>finding in a survey of undergraduate students who frequent dance clubs.
>E.g. in 10 subjects I looked at so far I found the mean loss at 250 was
>about 12 dB compared with 4 dB at 2 kHz.

>Dr Neil Todd
>Lecturer in Psychology
>University of Manchester
>tel. 0161 275 2557

end fwd

This archive was generated by hypermail 2b27 : Wed Jun 11 2003 - 13:08:52 EDT