In this study, the acoustic properties of spruce (Picea abies (L.) Karst.) and maple (Acer pseudoplatanus L.) lamellae with dimensions 400 mm × 75 mm × 3 mm were investigated. The acoustic properties of the lamellae were investigated dynamically-mechanically with the frequency response during free vibration bending. The lamellae were tested untreated and after surface treatment with four types of coatings: JOHA (J), domestic (D), nitrocellulose (NC), and polyurethane coating (PUR). After surface treatment, the average density of the lamellae increased, especially for spruce, and the natural frequency decreased significantly. The surface coatings, especially the softer ones (J, D, NC), especially for spruce, significantly increased the damping of mechanical vibrations (tanδ) of the lamellae after surface treatment. The acoustic properties of the lamellae changed the least after the surface treatment with polyurethane varnish, which significantly increases the density and thus the weight of the resonance plates. In contrast, the JOHA coating had the least effect on the weight increase of the resonance plates, and the negative effects on the relevant acoustic properties (Δtanδ = +28.24 %. ΔACE = -30.44 %) were relatively small.
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