Influence of the Grain Orientation of Wood upon Its Sound Absorption Properties

The purpose of the study was to analyze the influence of the quality class and the orthotropy of wood upon the sound absorption coefficient, the reflection and the impedance ratio of two species widely used for stringed musical instruments, namely spruce (Picea abies L. Karst) and maple (Acer pseudoplatanus L.). An impedance tube for the frequency range 100-6400 Hz was used in these experimental determinations. Knowing the influence of porosity and tortuosity on the acoustic absorption, these properties were also determined, as well as the sound reduction coefficient and the maximum values of the acoustic absorption coefficients in relation to frequency. The main results highlighted the differences between the anatomical quality class of the wood within each species, but also concerning the sound direction relative to the three main sections of wood, as an orthotropic material. The article highlights the acoustic performance parameters related to the frequency of the wooden material and its relationship to density, porosity and quality class. The results represent useful information for musical instruments manufacturers and more.

Automated summary

The study aims to analyze the impact of wood quality class and orthotropy on the sound absorption coefficient, reflection, and impedance ratio of spruce and maple, two commonly used wood species for stringed musical instruments. An impedance tube was used for experimental measurements in the frequency range of 100-6400 Hz. The study also determined the influence of porosity and tortuosity on acoustic absorption and the maximum values of acoustic absorption coefficients. The results highlight the differences in wood quality class and sound direction within each species and provide useful information for musical instrument manufacturers and more.