Three‐dimensional normal mode vibration plus acoustic analysis of two exemplary old Italian violins Free

A Polytec three‐dimensional scanning laser system capable of measuring in‐plane and out‐of‐plane violin corpus vibrations was used to measure mobilities in the top, ribs, and back of two exemplary old Italian violins, the 1715 Titian Stradivarius and the 1735 Plowden Guarnerius del Gesu, plus partial scans of the Willemotte Stradivarius (1734) and a Joseph Curtin (2006), back plate and top plate, respectively. The ratio of in‐plane to out‐of‐plane mobility was extracted for the first time for these violins over the frequency range of 0–5 kHz. Comparing only the averaged top plate mobilities of the 1715 Stradivarius and the 1735 Guarneri del Gesu with the 2006 Joseph Curtin revealed no important old‐new trend. Among the low‐lying (below 600 Hz) signature corpus modes, fit results for total damping revealed higher old Italian total damping only for the upper first corpus bending mode. Analysis of higher frequency damping behavior is currently under way. These measurements were accompanied by acoustic measurements over a sphere in an anechoic chamber of all these violins (plus a 2006 Sam Zygmuntowics violin) to compute radiation efficiencies for each violin.