Michael wrote (on the subject of coupled motions of piano strings): > I have a transducer that collects the signal of the motion of the > string excited by a grand hammer of an action model. My device > consists of a monochord with piano like terminations. The string > passes by two copper plates each about three inches long. The > string [.....snip....] > Since the plates are > perpendicular to each other they have the ability "see" the string > motion in two independent planes. [....snip....] > After a few milliseconds the motion begins > in the horizontal plane. This horizontal movement delay is when the > string moves after it has been reflected from the nearest > termination > point. I can see that time delay vary as I change the strike point > of the hammer in relation to the string. I can also detect differing > decay rates between the two planes of motion. Thi s verifies some > earlier work of Weinrich (1977 JASA, I believe). > You might like to check out the follwoing reference on this subject: F.L. Curzon, Classroon simulation of the coupled motion of piano strings, Am. J. Physics 52 (1984) 137-139 The author describes a contraption they built with an aluminum pipe and some springs to demonstrate the `Weinreich effect' as they call it...symmetric and anti-symmetric vibrations. Sounds like a mechanical version of your experiement...would be interested in seeing the results of your work. BTW the oringal paper by Weinrich is: J. Acoustical Soc. Amer. 62 (1977) 1474-? There is also the Scientific American article [240 (1979) p94-?] > I do plan to publish this when I polish up the experiment. I need > to eliminate > some confounding errors, organize my data, and prepare a > presentation. > How about video-taping your experiment. > I do not plan to have it published in a scientific > journal so it will probably end up in our "Journal". > Publish this somewhere at least...it sounds good? Stephen Birkett (Fortepianos) Authentic Reproductions of 18th and 19th Century Pianos Waterloo, Ontario, Canada tel: 519-885-2228 fax: 519-763-4686
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