Re: indefinite pitch


Subject: Re: indefinite pitch
From: Richard Wentk (richard@skydancer.com)
Date: Fri Oct 07 2005 - 07:26:17 EDT


At 12:04 07/10/2005, you wrote:
>on a slightly related note, last month(?)'s Scientific American ran a
>story on the background radiation of the universe and how it compares to
>these indefinate pitches - the diagrams looked awfully familiar to the
>shapes of the nodes produced by timpani.

Similar physics. Which is not to say that the two phenomena are necessarily
related. It's more that we only have one set of tools for describing
phenomena with harmonic content. So the same tools are used to describe
anything and everything, from drum heads to microwave distributions.

One of the problems that often seems to confuse the issue is that spectral
analysis is mathematically, not perceptually based. In the real world
there's no such thing as a precise frequency. Anything physical that
oscillates is more like a pitch cloud centred on a frequency, surrounded by
more or less obvious variations and deviations. Only digitally synthesized
sine waves are exact.

So the idea of 'pitch' is a perceptual abstraction in the first place, and
not an accurate description of what really happens. 'Indefinite pitch'
usually just means there are two or more frequency groupings that are
perceived as equally plausible as a root, and pitch perception remains
ambiguous.

Richard



This archive was generated by hypermail 2b27 : Sat Dec 22 2007 - 01:46:12 EST