### ASA 127th Meeting M.I.T. 1994 June 6-10

## 5pMU2. String vibrations in hammered dulcimers.

**David R. Peterson
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*Math. Dept., Central Arkansas Univ., Conway, AR 72035
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A unique characteristic of the hammered dulcimer is that the middle bridge
splits string courses into a length ratio of 3:2, so the two string segments
have an interval of a musical fifth. When the longer segment is struck,
coupling through the bridge to the shorter segment causes every third harmonic
to have two modes of vibration with slightly different frequencies, which
interact to produce vibrations with slowly varying amplitudes, which are
determined by bridge impedance, decay rates, and slight tuning differences. A
theoretical model has been developed, which applies to any number of strings
tuned to rational multiples. The distinct sound of the hammered dulcimer
depends upon the initial transient, which is strongly influenced by the
hardness of the hammer and the strike position.