Subject: Re: streams and groups From: Israel Nelken <israel(at)MD.HUJI.AC.IL> Date: Wed, 16 May 2001 15:58:17 +0300Dear list, Regarding the question about the transition from claps to applause: one limit is caused simply by the fact that the sum of many uncorrelated transients converges to a gaussian process (white noise if the transients are wideband). The signal-to-noise ratio of each individual component becomes progressively worse as you become more famous, until it is essentially masked by the background composed of all other claps. Thus, beyond a certain limit, it is essentially impossible to infer the properties of the individual transient from the summed response. I once made an experiment of summing sequentially more and more bird chirps in order to see when the statistics would become indistinguishable from gaussian, and it turned out that for my criterion of indistinguishability, about 5 simultaneously singing birds would be enough. Translated to claps, assuming that a clap is let's say about 50 ms long, assuming a rate of claps of 2/s, it means that you need about 50 people simultaneously clapping at uncorrelated times to go from individual claps into an applause. If you take into account some kind of cocktail party effect, you should multiply this number by the effective angular resolution of the CPE, which I guess is about 60 degrees, so in front of an audience occupying about 180 degrees you would need 150 people. Because of statistical variance, I guess these numbers should be multiplied by 2-3 to give a margin for fluctuations. This could be further elaborated, but I guess I'm already overdoing it :-). Any comments from people experienced at talking in front of an audience about the validity of these numbers? Eli Nelken -- ================================================================== Israel Nelken | Tel: Int-972-2-6757087 Dept. of Physiology, | Fax: Int-972-2-6439736 Hebrew University - | Hadassah Medical School | Note change in email address! P.O.Box 12272, Jerusalem 91120 | Email:israel(at)md.huji.ac.il ISRAEL | ==================================================================