Key signal and wood anatomy parameters related to the acoustic quality of wood for xylophone-type percussion instruments

Abstract

Wood percussion instruments have been part of culture since the earliest human societies. In making an instrument, the practical experience of musical instrument makers ensures its acoustic quality, especially with respect to selecting the most suitable wood species. The aim of this study was thus to gain further insight into the relationship between the physical properties and the perceptual classification of woods to be used in xylophone-type percussion instruments. A xylophone maker perceptually classified 58 tropical wood species, most of which are not usually used for musical instruments. Dynamic tests were then performed to record radiated signals. Key signal parameters pertaining to the acoustic quality of the material were extracted. Relationships between perceptual classifications, signal parameters, and wood anatomical characteristics were thus analyzed. It has been shown that percussive acoustic quality of wood, as determined empirically by the xylophone maker, can first be related to the temporal damping of the fundamental frequency. The samples tested in this study were not musically tuned; this could explain why no frequency descriptor was relevant. However, a draft anatomical portrait of a good acoustic wood could be drawn up. The organization of wood components in the tested species highlighted the importance of the regularity and homogeneity of the anatomical structures. The axial parenchyma seems to be the key trait. It should be paratracheal, and not very abundant if possible. The rays are another important feature; they should be short, structurally homogeneous, and not very numerous.