Holding the violin bow changes the support conditions substantially, but all prior analyses have investigated the bow either under free-free, or in a mechanically supported and/or clamped condition. The actual effects of hand-holding on the boundary conditions for the normal modes of the violin bow were investigated with hammer-impact modal analysis on an instrumented violin bow held in the hand of a violinist and compared to measurements on the bow suspended under free-free support conditions. Bow shaft motion was measured with a 0.5 gm accelerometer glued to the tip; an 18 gm force transducer mounted in the frog measured bow hair tension, and a roving near-field microphone was used to pick up bow hair motion. Overall little change was seen in held mode shapes (partly due to the influence of the force transducer mass) although reduced motion in the frog region was observed. Handholding dropped frequencies for the shaft modes an average of 2.2%, and hair modes by 1.4%; shaft mode damping increased by a factor of 2.4 while hair mode damping dropped 20%. Evidence for excitation of bow modes was seen clearly in bow hair tension and tip acceleration measurements during actual playing of the violin.
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