Subject: Re: auditory distortion caused by yawning From: "reinifrosch@xxxxxxxx" <reinifrosch@xxxxxxxx> Date: Sun, 19 Oct 2008 14:49:46 +0000 List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>Dear Harriet, Martin, Roger, Yi-Wen, and List, In a recent publication [1] I have proposed a "sensory- consonance condition b" (few or no large gaps in the pattern of partial-tone excitation peaks on the basilar membrane of the inner ear), to be added to "condition a" (i.e., to the Helmholtz consonance condition, few or no pairs of partial tones having nearly equal frequencies and thus generating disagreeable beats). Violation of my condition b, however, is perceived as disagreeable in the sense of "hollow", rather than in the sense of "dissonant" or "discordant". An increase of dissonance through yawning therefore appears to imply an increasing violation of the Helmholtz condition, i.e., a level increase of those pairs of partial-tone excitation peaks which even in comparatively consonant chords have nearly equal frequencies. For instance, in the major third consisting of two simultaneous harmonic complex tones C4 (264 Hz) and E4 (330 HZ), the sixth partial of the deeper tone has 1584 Hz, and the fifth partial of the higher tone has 1650 Hz. These two partials generate 66 beats per second, fairly close to the (broad) roughness maximum, discussed in [1], at a beat-rate of (1.1 s^-0.5) * sqrt(1617 s^-1) = 44 s^-1 . Second example: in the minor third consisting of two simultaneous harmonic complex tones E4 (330 Hz) and G4 (396 Hz), the fifth partial of the deeper tone has 1650 Hz, and the fourth partial of the higher tone has 1584 Hz. These two partials also generate 66 beats per second, close to the (broad) roughness maximum at a beat-rate of 44 s^-1. How can yawning selectively enhance the cochlear amplification at frequencies of about 1.5 kHz and higher? Possibly, increased dissonance perceived after yawning is caused by the active cochlear amplifier (CA) being turned off before yawning and turned on after. Near 300 Hz, the CA amplification factor is close to 1.0, whereas in the several-kHz region, in a healthy cochlea, that factor can be as high as 1000 (i.e., 60 dB). Reinhart. [1] R. Frosch, "Psycho-Acoustic Experiments on the Sensory Consonance of Musical Two-Tones", Canadian Acoustics, Vol. 35, No. 3 (2007) 38-45. Reinhart Frosch, Dr. phil. nat., r. PSI and ETH Zurich, Sommerhaldenstr. 5B, CH-5200 Brugg. Phone: 0041 56 441 77 72. Mobile: 0041 79 754 30 32. E-mail: reinifrosch@xxxxxxxx . ----Ursprüngliche Nachricht----------- Von: hjacobster@xxxxxxxx Datum: 17.10.2008 21:24 An: <AUDITORY@xxxxxxxx> Betreff: Re: auditory distortion caused by yawning I wouldn't imagine the hard cochlea being physically altered with just a yawn. I would think it would have more to do with change in middle ear pressure and TM mobility...much like we yawn to open our Eustachian Tubes. -------------------------------------------- Prof Roger K Moore wrote: > Dear List, > > I have often noticed that if I yawn while listening to music, I > experience a noticeable distortion of the auditory > experience - in particular, the sounds appear to become > discordant. Is this a well known effect, and can it be easily > explained as the result of a physical distortion of the > cochlea? If so, what does it say about timing-based theories > of timbre perception? > > Best wishes > > Roger K. Moore