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Acoustic Performance of Picea Resonance Board and Differences in Human Physiological Responses

云杉共振板声学振动性能与诱发人体生理响应差异


以红皮云杉、长白鱼鳞云杉、林芝云杉与西加云杉4种云杉属木材所制作的8块共振板为研究对象,基于各向异性薄板振动理论,测定共振板的弹性模量、纵波传播速度、振动响应时间等声学振动性能指标,并对同树种内的2块共振板进行比较得出: 同树种第2块共振板的弹性模量、纵波传播速度、边部试件的弹性模量大于第1块共振板,而振动响应时间小于第1块。将共振板制成钢琴后,研究人体心率变异、血压变异生理指标对钢琴乐音(肖邦前奏曲OP28: No.24)的响应。结果表明: 与听赏第1号钢琴乐曲相比,受验者听赏同树种第2号钢琴时,其迷走神经活动水平上升更大,受验者精神处于更为放松的状态。因此可认为: 弹性模量、纵波传播速度大而振动响应时间小的共振板,其声学振动性能更有益于产生良好的人体生理影响。

Spruce resonance board is one of the important components of piano, and its acoustic property affects the piano‘s acoustic quality largely. 8 pieces of resonance boards made from Picea koraiensis, P. jezoensis, P. spinulosa, P. sitchensis (every species has two pieces) were as the samples and their modulus of elasticity (MOE), propagation velocity of longitudinal wave (VL), vibration response time (Tr) and modulus of elasticity of the samples sawed from the edge of resonance board (MOEs) were determined based on the vibration theory of anisotropic plate. The result shows that the MOE, VL and MOEs of No.2 resonance board are larger, and Tr of No. 2 is smaller than the No.1‘s in the same species. Then the resonance boards were made to 8 pianos. And the response of human heart rate variability (HRV) and blood pressure variability (BPV) to the piano music (Chopin Preludes, OP28: No.24) was researched. The result shows that when the human enjoyed the No.2 piano‘s music in the same species, their vagus nerve activity increased more than that the No.1‘s, and they were in more relaxed state. That‘s that the human physiological indicators variety were larger for the No.2 piano in the same species. Therefore, it can be considered that larger MOE, VL and MOEs and smaller Tr of resonance board induce better effects in human physiology.