ASA 129th Meeting - Washington, DC - 1995 May 30 .. Jun 06

2aMU6. Anomalous low-pitched tones from a bowed violin string.

Roger J. Hanson

Phys. Dept., Univ. of Northern Iowa, Cedar Falls, IA 50614

Frederick W. Halgedahl

Univ. of Northern Iowa, Cedar Falls, IA 50614

Knut Guettler

Norwegian State Acad. of Music, P.B. 5190, Majorstua, 0302 Oslo, Norway

With a bow force greater than the Schelleng maximum and careful control, it will be demonstrated that it is possible to produce sounds on a violin of definite pitch ranging from approximately a musical third to a twelfth or more below the normal pitch. The lowered pitch is in agreement with the fundamental frequency of the observed harmonic series. The fundamental itself is very weak if the sounds are produced on the open G string. Mari Kimura has utilized the effect in performances [New York Times, 21 April 1994, p. B3, and Strings, Sept./Oct. 1994, 60--66]. These anomalous low frequencies (ALF) occur when the bow force is great enough to prevent the Helmholtz kink from triggering the normal release of the string from the bow hair. As a result of pronounced bow-nut and bow-bridge reflections there is at the bow a very complex string waveform, some portion of which regularly triggers the slipping of the string. ALF can also be produced on a bowed string mounted on a steel beam, where the motion is detected optically. Computer simulation is used to show how a string can be forced to vibrate at frequencies lower than the natural fundamental frequency of the string.