Chris: Strings of a "homogeneous" material (i.e. non-wound strings) are unlikely to be completely homogeneous at a molecular level. Chemical polymers have a molecular size distribution around some average length, and those various sizes are essentially randomly distributed throughout the bulk of the material. Metal strings have crystal grains of various sizes distributed randomly through the bulk of the material. For gut strings the inhomogeneity will extend to the macro structure as well, since they are composed of multiple strands of intestine twisted together.
What happens as the string ages under tension is that it gradually stretches. That is, it gets longer and thinner. (For a graphic illustration, pull on a rubber band and watch what happens.) As the stretching progresses, the microscopic variations in structure become manifest at the macroscopic level, as relatively thicker and thinner sections appear, and the elasticity of the string becomes slightly uneven along the length. In polymeric strings the molecules may slither around a bit. In metal strings, crystal grain boundaries may actually migrate slowly, or oxygen from the air may diffuse into the material along grain boundaries and oxidize the atoms on the surfaces of the grains, reducing the adhesion between the crystals so weaker sections appear. The almost immeasurable inhomogeneities in diameter and/or elasticity that result are apparent to the ear as variations in linear density of the string, which cause a) the harmonics to be out of tune with the fundamental, b) false pitches as the string is fretted up the neck of the instrument and c) eventually a loud bang as one short section of the string becomes too small in diameter and/or weak to support the tension applied. Regards, Daniel Heiman On Thu, 11 Aug 2005 06:58:27 -0700 (PDT) <[EMAIL PROTECTED]> writes: > Herbert, etc. > > > OK, why do violin strings go false? I don't hear > bowed string players complaining about lack of > brilliance, (maybe they do) but they do complain that > old strings won't play in tune. (This is a problem I > had whether the strings were new or not:-)) > > > Chris Wilke > > --- Herbert Ward <[EMAIL PROTECTED]> wrote: > > > > > After thinking all night, I believe/guess that > > deadness > > in strings is primarily caused by dirt in the > > windings which dissipates the vibrational energy, > > as sand dissipates your tranlational energy > > when you ride a bicycle on a beach. I think > > that this dissipation preferentially attacks > > the upper harmonics, causing the characteristic > > lack of brilliance. > > > > > > > > To get on or off this list see list information at > > > http://www.cs.dartmouth.edu/~wbc/lute-admin/index.html > > > > > > > ____________________________________________________ > Start your day with Yahoo! - make it your home page > http://www.yahoo.com/r/hs > > > > >
