Acoustic Vibration Performance Detection And Analysis Of Several Typical Folk Instruments Wooden Resonators

This paper describes and analyzes the status quo of the musical instrument soundboard’s material in the home and abroad, and the vibration performance and processing of Chinese instruments resonance’s material. It can be seen by analyzing, although the instrument practitioners and researchers have recognized the important role of timber for musical instruments, but it mainly confines to the test of timber vibration properties on the research of our folk instrument’s acoustic vibration performance. Moreover, it just gives a brief introduction about the material and processing of the timber for musical instruments, and it has no substantive scientific validation test. To solve the problem, the paper does depth study on the timber for musical instruments resonance components, the independent resonance components and the finished instrument resonate components. The specific contents are as follows:1) Study on the materials election of folk instrument on the basis of texture image detection technology according to the texture analysis ideological which is based on statistics. Take the texture spacing matrix that can response the plank texture density level as the characteristics to determine its applicability for the production of musical instruments. Obtain the respective texture spacing matrix through the texture spacing estimates of the wood panel for the production of lute, nguyen, yueqin three instruments. It analyzes the relationship between texture width and vibration performance, and provides a certain scientific theoretical basis and technical support for the apperarance primaries of the resonance panel wood.2) Analyze and detect the main feature that can affect the sound quality of musical instrument-the general principles of the vibration characteristics and the method of the testing experiments, discover and initially establish the acoustic properties detection methods of the timber components for folk instruments resonate, and establish the experimental environment for detection. On the basis of the previous studies, choose the materials for the experiment combined with the practical experience of the musical instrument production division, and analyze the acoustic vibration performance of the materials. We can use the vibration performance of the timber for resonance panel to evaluate the vibration properties of the materials objective. The paper distinguishes the acoustic vibration characteristics of the selected stringed instrument resonance panel.3) Study the acoustic vibration performance of the instrument soundboard by using the combination of the experimental modal analysis and calculation modal analysis on the basis of the sheet dynamics, and select the natural frequency, damping ratio and mode shapes as the parameters on the basis of the modal characteristics. Determine the experimental method of the experimental modal analysis on the basis of the lute, yueqin, and nguyen instrument soundboard’s composition characteristics. Determine the undamped free vibration equation and the r-order modal vibration coefficient matrix of the modal analysis thin circular plate according to the principle of vibration, and the relationship between displacements and curvature, curvature change rate, the bending moment. Analyze the vibration moden of the instrument resonance panel, and the result shows that the order vibration model shaps of yueqin and nguyen’s resonance panel substantially appears symmetry of longitudinal axis (along grain direction, y-axis) and horizontal axis (horizontal grain direction, x-axis), but lute’s resonance panel only appears symmetry of longitudinal axis.4) On the basis of the acoustic properties detection method of the timber components for folk instruments resonate, comprehensively analyze the all parameters of the resonance members acoustic quality, select the objective indicators of the effective characterization resonance acoustic properties. Detect and analyze the surface wave propagation velocity of resonance component and the radiation intensity of resonance component acoustic. Test the surface wave propagation velocity of lute, yueqin, nguyen three instruments resonance component and the acoustic radiation intensity of lute, yueqin, nguyen, erhu four instruments resonance component along the texture direction, twill direction, horizontal grain direction, and draw the corresponding law. The surface acoustic wave propagation velocity and acoustic radiation intensity values of lute, yueqin, nguyen three musical instruments resonance panel are the minimum, and their acoustic radiation intensity value in the resonance component stage is the maximum, the acoustic radiation intensity of each instrument in three-stage trends the same toward. The surface wave propagation velocity speed in the cross-grain direction resonance box stage is fastest, and in the other directions is staggered, and the overall is mainly to the greater value of the resonance box’s surface wave propagation velocity speed. The acoustic radiation intensity value in lute resonance component stage is the maximum, but the trend of three types of wood’s acoustic radiation intensity values in resonance box stage and in resonance component stage are precisely reversed, the original maximum value turns into the minimum value.The research of the system is used for timber of resonance wood component (material), sounding board, resonance panel, resonance wood component that is used to make independent component, a component of the assembled musical instrument, and the intrinsic relationship between its and the acoustic quality of the finished instrument and, and find the main factors that can affect the acoustic quality. It provides the research base for the realization of the scientific selection which is used to provide the the national musical instrument resonance in organic combination of the musical instrument production master’s practical experience.