Effect of heat treatment on the acoustic properties of a wooden xylophone keyboard

To estimate changes in the acoustic properties of a wooden xylophone keyboard caused by heat treatment, the resonant frequencies and logarithmic decrement of control and heat-treated specimens of Yezo spruce (Picea jezoensis), Northern red oak (Quercus rubra) and Japanese red pine (Pinus densiflora S. et Z.) were evaluated by the free vibration method. A flexural vibration test was carried out by the xylophone stick free fall impact test. The changes in resonant frequency of the first mode and those of other modes by heat treatment were evaluated. And the changes in logarithmic decrement by heat treatment were evaluated. As a result of heat treatment, the resonant frequencies of the 1st mode of all specimens were decreased, and within a species the wood specimens of higher resonant frequencies were more influenced. In the case of the specimen with a higher resonant amplitude at the 2nd mode resonance frequency, the resonant amplitude of the 1st mode resonance frequency was increased more by heat treatment, so that the sound became more stable.