Subject: Re: Gaussian vs uniform noise audibility From: Israel Nelken <israel(at)MD.HUJI.AC.IL> Date: Tue, 20 Jan 2004 07:36:18 +0200The auditory system (and auditory neurons) can certainly distinguish between stimuli based on their amplitude distribution. Uniform noise sounds more 'smooth' than gaussian, and gaussian sounds more 'smooth' than heavier-tail distributions like Cauchy. At the limit, consider the fact that a Poisson sequence of clicks has a flat spectrum, like white gaussian noise, but sounds completely different. Amplitude distributions in time are related to correlations across frequency. In gaussian noise, the amplitudes and phases of the different frequency components are independent. In non-gaussian noise, even with white power spectrum, amplitudes and/or phases are correlated. The auditory system is sensitive to correlations across frequency. For amplitudes, consider for example comodulation masking release and related work about monaural correlation detection (there's a nice paper of V. Richards in JASA many years ago about that). We are also sensitive to correlation in phases across frequency components that fall within the same peripheral filter, and to the phases of envelopes even across wide frequency separations (see some interesting modeling work in: Carlyon RP, Shamma S., An account of monaural phase sensitivity. J Acoust Soc Am. 2003 Jul; 114(1): 333-48). Eli -- ================================================================== Israel Nelken Dept. of Neurobiology The Alexander Silberman Institute of Life Sciences Edmond Safra Campus, Givat Ram | Tel: Int-972-2-6584229 Hebrew University | Fax: Int-972-2-6586077 Jerusalem 91904, ISRAEL | Email: israel(at)md.huji.ac.il ==================================================================