Radiation damping, efficiency, and directivity for violin normal modes below 4 kHz

Abstract

Simultaneous modal and acoustical measurements on three violins characterized the physical chain from bridge to sound below 4 kHz via normal mode rms mobility and radiativity, total damping, radiation efficiency, and averaged directivity. The fraction of vibrational energy radiated as sound was estimated as 31%±10% for the 1st corpus bending modes. Radiation efficiencies ranged from ∼0.004 to ∼1, rising with frequency, with lower and upper 1st corpus bending mode values of 0.12±0.03 and 0.11±0.04 respectively. Averaged directivity rose slowly from ∼1 for the lowest modes to ∼2 at 4 kHz. The A1 cavity mode radiates effectively via induced corpus motion.