source file: mills2.txt Date: Wed, 26 Feb 1997 21:02:00 -0800 Subject: Sympatheti c Strings From: Lydia Ayers Paul Erlich wrote: >The cross-sectional area of a string is almost negligible compared with that >of a tube or plate. Thus the string will receive almost no energy from >incident sound waves, while a broader object can absorb significant amounts >of energy. The cross-sectional area of a string may be "almost negligible" but it exists. I just performed some experiments on four stringed instruments in my collection, a cheap violin, a sanxian, a small zheng and an Appalachian mountain dulcimer. Of these, I got the best results from the violin and the sanxian. On the violin, I got the best results on the A and E strings, with the E string sounding louder. I don't have a scientific way of measuring the guage, but it looks like the violin E string is the thinnest of all the strings on all four instruments. It is also unwound wire and tightly stretched. The timbre of the sympathetic resonance is similar to the plucked string timbre. The second best results came from the sanxian. The strings are longer than those on the violin, and I think they're made from wound silk. They look like they're just a little bit thicker than the G and D strings on the violin. The timbre is similar to the plucked string timbre. Both the violin and sanxian have excellent resonators, with the sanxian having a small, round, snakeskin-covered box. My small zheng (Chinese zither-type instrument) has thin wire strings between the thickness of the A and E strings on the violin). I didn't have time to find the tuning key right now to tighten them, so they aren't really tightly stretched. The resonator is much bigger than that for the violin - it's basically a wooden box that all the strings are mounted on, with holes in the bottom. It worked better when I picked the instrument up so that the sound could come out the small holes, but the resonance still wasn't very loud. Maybe the large moveable bridges don't transmit the sound as well to the soundboard. The dulcimer has nylon strings slightly thinner than those on the sanxian. I can't really account for why this one is not very loud. Maybe metal strings work better than nylon? Maybe the resonator doesn't amplify the sound very well? I got these results by loudly singing the same pitch as the string is tuned to, as close to the plucking area (and the string itself) as possible. Singing a different pitch from the pitch of the string does not give the effect, so it seems unlikely that the sympathetic vibration comes from exciting the resonator. I think the original excitation must be airborne, and the strings sound louder if they have good resonators. Lydia Ayers Received: from ns.ezh.nl [137.174.112.59] by vbv40.ezh.nl with SMTP-OpenVMS via TCP/IP; Thu, 27 Feb 1997 08:15 +0100 Received: by ns.ezh.nl; (5.65v3.2/1.3/10May95) id AA28778; Thu, 27 Feb 1997 08:15:32 +0100 Received: from ella.mills.edu by ns (smtpxd); id XA28787 Received: from by ella.mills.edu via SMTP (940816.SGI.8.6.9/930416.SGI) id XAA10683; Wed, 26 Feb 1997 23:13:56 -0800 Date: Wed, 26 Feb 1997 23:13:56 -0800 Message-Id: <199702270213_MC2-11C6-1B7D@compuserve.com> Errors-To: madole@mills.edu Reply-To: tuning@ella.mills.edu Originator: tuning@eartha.mills.edu Sender: tuning@ella.mills.edu