At 12:40 -0700 14/7/10, Susan Kline wrote: >>Now I am told that the first overtone of a tuning fork has about 6 >>1/4 times the frequency of the fundamental, so where is this octave >>coming from? > >Beg pardon? > >Do you mean 6 1/4 times the volume of the fundamental? No, I mean what I said. A vibrating string has the octave (or something very close, taking inharmonicity into account) as its first overtone, but a tuning fork doesn't behave anything like a string. At 14:16 -0500 14/7/10, Ron Nossaman wrote: >It's coming from the handle. You get pulses at the bottom of the >handle because the fork changes length slightly as the tines >vibrate. It's longest when the tines are straight, and shortest when >the tines are at *both* the inner or outer limit of their excursion. >This happens twice with each full excursion of the tines, so the >contact pulse at the handle bottom is twice the frequency of the >fundamental. Yes, that makes perfect sense, except that rather than say the "fork changes length" I picture a longitudinal yoyoing of the whole fork caused by the fluttering of the tines. I'm still curious to know, though, what causes the differences in relative volume of this mode according to the position of the fork on the board. JD
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