V-R model predictions of averaged radiation from a violin compared with spatial average of bridge force hammer-excited direct radiation

Abstract

Mechanical modal analysis data for a violin furnish two essential components for the vibration-radiation (V-R) model [G. Bissinger, J. Acoust. Soc. Am. 97, 3154–3164 (1995)] to reliably predict the averaged radiative properties of a bowed string instrument from its measured mechanical properties, viz., (1) how strongly a particular corpus mode is excited at the bridge and (2) normal mode frequency and shape data for boundary element acoustic radiation calculations of the radiation efficiency for each corpus normal mode. Combining both of these elements in the V-R model gives predictions of a spatially averaged acoustic radiation for a violin. These were compared with similarly spatially averaged measurements of direct radiation from a violin excited by force-hammer impact at the bridge using a rotating semicircular (r=30 cm) seven-microphone array in a small anechoic chamber covering almost an entire sphere around the violin. The V-R model calculations for each mode compared quite well in general to the measured average radiation.