Kent: The sine waves that I combined together to make the wave file I posted show no measureable overtones using Tunelabs Inharmonicity tool. Neither could Cybertuner pick anything up. Now the phase display that Tunelab has showed a very intermittent response at around 880 for the 440 signal. This response faded in and out and its frequency wavered quite a bit. I doubt that this is an overtone per se. I fail to see how these non existing coincidents can account for the beat rate in the wave file. And so I question whether or not it is there. This echos Ed's and others ponderments and its a fair question. And I dont see that simple coincident partials theory provides an answer to it. Every link I find that describes tuning forks describes them as instruments that have (for all practical purposes) no overtones. Such as the below. Several sights which describe experiments like the one you did with your cybertuner attribute (sometimes) presence of very weak overtones that are not accounted for by the design of the tuning fork to sympathetic vibration from surrounding material... such as what ever you grounded your tuning fork on. John Walker tuning forks make a real big point out of emphazising the <<overtone free>> characteristic of their tuning forks in all their advertising. One other point. The duration and strength of your <<overtone>> is not sufficient to account for the long duration and intensity of the beating between the fork and the non coincident F3. I say something doesnt add up. Cheers RicB http://hyperphysics.phy-astr.gsu.edu/Hbase/music/tunfor.html
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