Date of this Version
Wang, L. M. and C. Burroughs. (1999) “Directivity patterns of acoustic radiation from bowed violins.” Catgut Acoust. Soc. J. 3 (7), 7-15.
Directivity patterns of acoustic radiation have been measured in the far-field of a violin, excited with an open-frame mechanical bowing machine. Analysis of the directivity patterns confirms that, at frequencies below 600 Hz, the violin radiates omnidirectionally, while above 600 Hz, certain trends are apparent as the patterns become increasingly complex. It is noted that when different strings are excited, the far-field radiation patterns observed at nearly the same frequency are similar, even in higher frequency ranges where modal overlap is high. When the difference in frequency between two directivity patterns exceeds some fraction of a semitone, though, the measured radiation patterns differ significantly. This is demonstrated quantitatively by computing an rms difference around the polar plots between patterns. The sensitivity of the directivity patterns to percent changes in frequency increases with frequency.