Frequency responses of wood for musical instruments in relation to the vibrational properties

Abstract

The frequency response and the Young's modulus, shear modulus and internal friction were measured for square boards with regularly-grained planes in several kinds of wood, which included Sitka spruce for stringed instrument top plates and maple for back plates, and for square boards in an acrylic resin of plastics and an aluminum of metals. The Sitka spruce was the highest in response frequency, higher in sound power level, the greatest in level variation and the greatest in level drop with increasing frequencies above 1 kHz, and it had the response pattern of high level in the range of middle frequencies. In contrast, the maple had the response pattern of low and almost flat level as a whole. In order to have such frequency responses, it was necessary that wood for top plates had not only the excellent vibrational properties in the direction along grain but also the strong anisotropy in regularly-grained plane, and that wood for back plates had the characteristics opposite to those of wood for top plates.