Subject: Re: TTS as surrogate for noise exposure measurement From: Andreas Widmann <widmann@xxxxxxxx> Date: Fri, 19 Apr 2013 13:24:57 +0200 List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>Hi David, > Since the original question was really about sound levels at the ear drum while wearing headphones, Sorry, no, to my understanding one approach of the original question was to define a "standard loudness" by a particular sound: >> One problem is that I can't think of any household sounds >> with a standard loudness. > I don't see a straight forward way of getting at this with a cell-phone app since you can't stick the phone in your ear. Perhaps we could come up with simple design for a 2 cc coupler that could couple the headphone to a cell phone microphone.. That sounds like a very interesting idea, indeed. I would be definitely interested in such a design! Best, Andreas > On Tue, Apr 16, 2013 at 4:01 AM, Andreas Widmann <widmann@xxxxxxxx> wrote: > > Since this is just for "casual" purposes, not research, > > etc, he'd probably be happy with some sort of rule-of-thumb > > metric... > iPhone available from family/friends? The iPhone microphone has a reputation of being calibrated quite well. There are dozens of dB-meters of any kind in the App Store. In a German computer journal "Noise Immission Analyzer" (https://itunes.apple.com/de/app/noise-immission-analyzer/id518336921?mt=8) got quite nice comments recently. > > Not research grade but should be god enough for rule-of-thumb metric. > Best, > Andreas > > Am 15.04.2013 um 15:02 schrieb Bob Masta <audio@xxxxxxxx>: > > > 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 > > measurements. > > > > 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. > > (Anyone?) > > > > 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 > > approach? > > > > 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 > > www.daqarta.com > > Scope, Spectrum, Spectrogram, Signal Generator > > Science with your sound card! > > > > > > -- > > David C. Mountain, Ph.D. > Professor of Biomedical Engineering > > Boston University > 44 Cummington St. > Boston, MA 02215 > > Email: dcm@xxxxxxxx > Website: http://www.bu.edu/hrc/research/laboratories/auditory-biophysics/ > Phone: (617) 353-4343 > FAX: (617) 353-6766 > Office: ERB 413