Characterizing violin top plate using sounds generated by local taps

Abstract

We analyzed the characteristics of sounds generated by local taps on a violin top plate. We examined the gravitational center of the frequency spectrum of tapping sounds and investigated its distribution over the top plate. The results showed that three categories of violins, with two violins in each category, had similar characteristics within the categories. The top plates of violins made after the 19th century in northern Italy had a high centroid frequency around the f-holes, and the tops of older Italian violins made before the 18th century showed a high centroid frequency only around the chin rest area, which was probably due to repeated coating with varnish. In addition, violin top plates with adjusted thickness of the wood to even out the pitch of the tapping sounds over the entire plate showed centroid frequencies with small variability over the top plates, similar to the old violins except around the chin rest area. These results indicate that violin top plates can be characterized by the sound of local taps on the violin plate, and suggest that tapping was an effective means of adjusting the thickness of the wood, especially before the early 19th century.