Re: High-frequency hearing in humans ("Hermes, D.J." )


Subject: Re: High-frequency hearing in humans
From:    "Hermes, D.J."  <D.J.Hermes@xxxxxxxx>
Date:    Fri, 4 Feb 2011 16:53:53 +0100
List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>

Just to show that it is not a simple question of loudspeaker quality but also of recording quality I send you a Matlab script producing one square wave "sampled" at 48000 and another at 192000 Hz. The difference is audible through any loudspeaker. clear all sf1 = 48000; sf2 = 192000; dt1 = 1/sf1; dt2 = 1/sf2; du = 1; f0 = 5000; t1 = 0:dt1:du; t2 = 0:dt2:du; s1 = square(2*pi*f0*t1); s2 = square(2*pi*f0*t2); sound(s1, sf1) wavwrite(s1, sf1, 's48000') pause(1) sound(s2, sf2) wavwrite(s2, sf2, 's192000') Best, Dik > -----Original Message----- > From: AUDITORY - Research in Auditory Perception > [mailto:AUDITORY@xxxxxxxx On Behalf Of Joachim Thiemann > Sent: vrijdag 4 februari 2011 15:37 > To: AUDITORY@xxxxxxxx > Subject: Re: [AUDITORY] High-frequency hearing in humans > > On Thu, Feb 3, 2011 at 23:08, Kevin Austin <kevin.austin@xxxxxxxx> > wrote: > > A colleague of mine has been working on clicks in an electroacoustics > aural perception course. He discovered that a 48kHz sampling rate was > "too crude", and that working at 96kHz (or higher), the differences > between clicks over 8kHz were noticeable. This is not quite what > sampling theory seems to say. At 44.1kHz, a single sample click > represents 22kHz, and a two sample click represents 11kHz. How does one > represent a 16kHz click with a 44.1kHz sampling rate? > > I think one has to be careful about the actual D/A hardware in these > cases. Oversampled sigma/delta? R-2R? What are the postfilter > characteristics? I think with these type of stimuli, differences > might be audible: even if the same soundcard is used at different > rates, the filter should change. The differences in filter > characteristics might extend to lower frequencies, where they might be > picked up by individuals with good hearing. > > Joe. > > -- > Joachim Thiemann :: http://www.tsp.ece.mcgill.ca/~jthiem


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