On Tue, 27 Nov 2007, Mark Constable wrote: > On 2007-11-27 12:22 pm, Rene Herman wrote: >> Mmm, and now that I look at it again: >> ampl = 32767.0 / pow(10, -dbfs / 20); >> is the same as: >> ampl = 32767 * pow(10, dbfs / 20); >> which looks somewhat nicer. > > How about a copyright, license, contact and version info, > and a bit of a readme in the header comments ? > > I'd like to package it and maybe try to wrap some kind > of simple Qt4 GUI hearing test applet around it, one day. > > It would be really cool to have some proggie that could > be run, every 3 months or so, to test ones hearing and > keep the results in SQLite (or online) and also provide > some kind of Jack/ALSA based EQ bias based on the stored > results. Like, ultra cool. Well, yes, as a comparison, assuming that you used exactly the same headphones and the same volume it could be useful. Otherwise useless. There is a HUGE difference between headphones and between the voltage output from sound cards and amps. Esp headphones can differ by 20dB and have that kind of bumps in the response curves. Also psychoacoustic effects come into play. especially near the threshold of hearing you thing you can hear something when you cannot. Thus audiologists will sweep down from a high freq to a lower one at a constant level and you indicate when you can hear it. Having you do it to yourself is not a good idea. Another possiblitity is to have the program randomly produce tones and you push a key if you think you hear something. By making both the ampl, volume and timing random, you can detect false positives. > > I recently got some good cans and a headphone amp and I > am amazed at what I can now hear, and NOT hear, so it > would be genuinely useful to have a custom EQ thingie > that I could apply to any computer (at least) generated > music that adapted to my failing ears over the years. > > A point is that these kind of "hearing tests" are almost > useless in absolute terms but are indeed meaningful when > tested and accumulated results are compared with for any > particular individual. The consistent mean is to set up > the listening environment to just be able to hear 1khz > at (about, I forget the right level) -50db and then run > the rest of the tests from that reference. As long as > this reference marker is used for each testing session > then the results can be reliable for that individual. ?? And that particular pair of headphones (and another of the same brand can be different significantly) And placing them on your head in exactly same way ( esp for "on the ear" or "in the ear" resonances in the aural cavities can change the amplitude a lot) . > > --markc > > ------------------------------------------------------------------------- > This SF.net email is sponsored by: Microsoft > Defy all challenges. Microsoft(R) Visual Studio 2005. > http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ > _______________________________________________ > Alsa-user mailing list > Alsa-user@xxxxxxxxxxxxxxxxxxxxx > https://lists.sourceforge.net/lists/listinfo/alsa-user > -- William G. Unruh | Canadian Institute for| Tel: +1(604)822-3273 Physics&Astronomy | Advanced Research | Fax: +1(604)822-5324 UBC, Vancouver,BC | Program in Cosmology | unruh@xxxxxxxxxxxxxx Canada V6T 1Z1 | and Gravity | www.theory.physics.ubc.ca/ ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2005. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Alsa-user mailing list Alsa-user@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/alsa-user
