Subject: Re: Critical bands v hearing loss From: Martin Braun <nombraun(at)TELIA.COM> Date: Wed, 28 Sep 2005 16:44:07 +0200Jan Schnupp asked: > ......... the impression I > have is that, when it comes to auditory scene segmentation, critical > bands are not that critical. Or am I wrong there? You are probably right. The critical band (CB) anatomy can support scene segmentation, but it is not a necessary element in it. Scene segmentation is mainly accomplished on the basis of temporal disparities between signal streams. And such disparities are largely extracted and coded already in the cochlear nuclei, that is before the CB anatomy in the midbrain is involved. The main function of the CB anatomy seems to be spectral segmentation for pitch extraction and timbre recognition. As to the issue of frequency resolution and CB (Reinhart Frosch): -- Difference limen for frequency (DLF) in the range of 0.5 to 2 kHz is ca 3 Cent. -- CB in the range of 1 to 4 kHz is 260-280 Cent. Original CB data: Zwicker, E., Fastl, H., 1990. Psychoacoustics: Facts and Models. Springer-Verlag, Berlin. (Table 6.1) Original DLF data: Wier, C.C., Jesteadt, W., Green, D.M., 1977. Frequency discrimination as a function of frequency and sensation level. J. Acoust. Soc. Am. 61, 178-184. (Table II) Transformation of the CB and DLF data into Cent: Braun, M., 1999. Auditory midbrain laminar structure appears adapted to f0 extraction: further evidence and implications of the double critical bandwidth. Hear. Res. 129, 71-82. (Fig. 5) Martin ---------------------------- Martin Braun Neuroscience of Music S-671 95 Klässbol Sweden web site: http://w1.570.telia.com/~u57011259/index.htm