source file: m1482.txt Date: Thu, 23 Jul 1998 09:34:28 +0100 (British Summer Time) Subject: Re: TUNING digest 1481 From: David Griffel On Wed, 22 Jul 1998 23:48:07 +0100 (BST) tuning@eartha.mills.edu wrote: > > Can somebody in this forum help me understand the concepts of overtones and > tone color? For example, A440 produced by a tuning fork consists of > vibrations having frequencies of mostly A440. But A440 played on a piano or a > tuba will have more overtones, frequencies that are multiples of 440 - 880, > 1320 etc. This is were I lose it. Are overtones different frequencies > produced by different aspects of whatever materials are producing the sound? > So if the sound is being created by simpler materials such as a tuning fork, > the will be fewer other frequencies involved, whereas if the sound is created > by a piano, the hammer and string are more complex materials and therefore > have more frequencies or overtones? It's not the materials, it's the way that things vibrate. Here's an oversimplified description. A pure vibration like that of a tuning fork is a simple smooth "sine wave" of frequency 440, say. A more "jerky" vibration of frequency 440 is mathematically equivalent to the combination of smooth sine waves of frequencies 440, 880 etc., the bigger the component of the overtones, the more complicated is the resulting waveform and the "richer" is the sound. The way that the vibration is set up determines what sort of waveform it gives, and hence determines the timbre. Basic books on musical acoustics will explain this with diagrams, much better. perhaps the Just Intonation web site has book references? David Griffel ------------- School of Mathematics, email d.griffel@bris.ac.uk University Walk, Tel. 0117 928 7983 Bristol, BS8 1TW, Fax 0117 928 7999 England.