Subject: Re: First moment of spectrum From: "Alain de Cheveigne'" <Alain.de.Cheveigne(at)IRCAM.FR> Date: Wed, 14 Jun 2000 21:27:32 +0100Pierre, I don't think anyone suggested that a spectrum can be reduced to its first moment. I'm sure we both agree that psychophysics is a suspicious business, but many people have tried to relate physical quantities to perceptual dimensions. Spectral centroid is perhaps one of the more successful attempts. My comment on Al's question was mainly to point out that the "physical dimension" spectral centroid (first moment) is not completely straightforward, because there are several plausible ways to calculate it. It's not just that they give different values: you can have awkward situations where sound A scores higher than B on one scale but lower on the other. This said, I wholeheartedly agree with your reminder that we should resist the temptation to reduce everything to such simple measures. By definition, any physical difference that's not masked suffices to make two stimuli sound different, and that leaves plenty of room for interesting dimensions! Alain