漆膜厚度对云杉属木材吸声性能的影响

音板是钢琴最重要的部件之一,是影响钢琴声学品质的关键因素,其制作材料吸声性能好坏很大程度上决定了钢琴音量大小和发音持久性。云杉属木材是制作钢琴音板的主要材料,本研究以4种云杉属径切板木材作为研究对象,采用驻波比法测试了4种木材的吸声系数以及在不同漆膜厚度情况下的吸声系数并进行比较,初步分析了漆膜厚度对云杉属木材吸声性能的影响。结果表明:在无漆膜状态下,麦吊云杉吸收的声能最少; 而在有漆膜状态下,除了漆膜厚度是0.15 mm时,4种云杉属木材吸声系能不稳定之外,吸声系数是随着漆膜厚度的增加而增加,即漆膜厚度越小,钢琴音板的吸声性能越差。
Any material can absorb sound but the degree of sound absorption is different. As a vibrating diaphragm, the soundboard is one of the most important parts of the piano, and it should reflect out more sound energy. So the sound absorption performance of its materials largely determines the volume and duration. The four spruce woods including Picea glehnii, P. abies, P. sitchenrsis carr, and P. brachytyla that mainly used for making piano soundboard were selected to study in the manner of thickness of 10 mm and diameter of 50 mm and 100 mm. The sound absorption coefficient of the four spruce woods were tested with standing wave ratio method. Their sound absorption characteristics among different trees, different frequency and different film thickness with 0.15, 0.30, 0.45 and 0.60 mm were compared, and the effect of paint film thickness on sound absorption characteristics of spruce woods was analyzed. The results showed:the sound absorption coefficient of unvarnished P. brachytyla is minimal; and in the measurement frequency range, absorption coefficient is increased with the increase of film thickness except unstable sound absorption performance with 0.15 mm film thickness; the piano soundboard sound absorption performance is poorer with the smaller film thickness. So, in conclusion, the difference between sound absorption performance of the four spruce woods is small, but the surface coating thickness on the piano soundboard affects the sound absorption performance of the material. As a protective film, paint film can prevent the buckling and deformation. The manufacturers should adopt the thinner film thickness in the process of soundboard production which would make it as far as possible to reflect more sound energy and enlarge the volume