At 4:34 PM -0500 1/23/03, Sarah Fox wrote: >Very cool. Now I know the name. <smile> Just to expand on this >concept, if the impulse (i.e. hammer blow) delivered to the string >has both vertical and horizontal components, and if the vertical and >horizontal components are not simple scalar translations of each >other (i.e. that the horizontal force is a fixed multiple of the >vertical force, such that they could be resolved as a simple, >unidirectional impulse at an angular direction -- highly doubtful), >then the initial horizontal and vertical spectra would have >different relative representations in the different harmonics >(partials). As a result, the resultant angle of vibration would >differ between harmonics. (Think about it.) Now, considering the >inharmonicity of the string, the phasing of the different harmonics >would drift. As they drift, angle of vibration at any given >position of the string would also drift, i.e. being the sum of the >vibrational components from each harmonic, which arguably are set at >different angles in an imperfect system. Add to the cocktail that >nonlinearities in string behavior would result in the gradual >transfer of energy from lower frequencies to their harmonics in >the *same* vibrational direction as the lower frequencies, with >those frequencies summating with the (slightly different frequency) >harmonics at different vibrational angles, thus causing a shift in >the angle of the resultant vibrational component. YOW!! >WOW!! This could make a person's brain bleed! You really enjoy "writing out loud", don't you. (Me too, along with bypassing the shellch-ecker <g>). The story which I heard is from Barney Ricca, former PTG member, actually a physicist at one of the Texas universities. At the '95 Albuqueque National, he was summarizing the conventional wisdom, saying that in the initial impact, this wave form in the string , viewed axially, would be purely vertical. This would last for a short interval (proportional to the total sustain time) until the string's energy would spill into the other (infinite) modes, to remain stable in that chaotic "omni-mode". The initial single mode is actually the prompt sound, that time period when the string is feeding rapidly into the bridge. Entropy compels the vibrations into a choatic mode which fortunately for us, also extends its sustain. This latter phase is called the aftersound. But what do I know, I've barely got a high school diploma. Bill Ballard RPT NH Chapter, P.T.G. "Woh" ...........Keanu Reeves in "The Matrix" +++++++++++++++++++++
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