> I've been contacted by a young person in Hungary who is
> concerened that his music listening habits may be damaging
> his hearing. He saw that my Daqarta software has a built-
> in SPL meter feature, and he wanted to know how to use it
> to measure the headphone level of his music, so he could
> keep it under 80 dB SPL.
> Unfortunately, he says he can't afford a calibrated
> microphone, which would of course be needed for any SPL
> Since this is just for "casual" purposes, not research,
> etc, he'd probably be happy with some sort of rule-of-thumb
> metric... but I don't know of any. I'm thinking here of
> non-technical things like they recommend for aerobic
> exercise, such as "walk fast enough so that you can just
> barely carry on a conversation"... only for hearing.
> One problem is that I can't think of any household sounds
> with a standard loudness. Another is that if he already
> has some PTS he would get false assurance that his
> listening levels were not too loud.
> So my question for the group is about using TTS. The
> beauty of this is that it requires no absolute calibration.
> He could measure his threshold at some specified frequency
> in the morning before he starts his music listening, and
> record the level in dB relative to full scale (whatever it
> might actually be), then repeat it after listening and take
> the difference. He can use Daqarta to do this for free.
> I think if he finds *any* shift it means his music is too
> loud, but the converse is probably not true... especially
> if there is already some PTS, which would presumably reduce
> the amount of TTS. True? Any thoughts on this whole
> I have discarded one possible alternative approach, which
> would be to listen at his usual level, then reduce the
> level until he can just barely hear it and record how much
> reduction that took. The problem with this dB-above-
> threshold measurement is once again that if there is PTS
> his higher threshold would make his music measure softer.
> Any other ideas?
> Thanks, and best regards,
> Bob Masta
> D A Q A R T A
> Data AcQuisition And Real-Time Analysis
> Scope, Spectrum, Spectrogram, Signal Generator
> Science with your sound card!