A Study on The Acoustic Fidelity Affected by the Materials of Zheng，s Bridges
| Autor: | LIN,KUO-I, 林國義 |
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| Rok vydání: | 2006 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 94 Bridges are the most direct acoustic fidelity elements of the Zheng. They transfer the energy of the strings to the board and bring the board vibration by means of coupling the bridges with the board. Then the resonance box releases the energy to achieve acts and the acoustic fidelity heard by audience. Besides, bridges can change the acoustic fidelity of a Zheng most. The theme of this paper is on how materials of the bridges can affect the acoustic fidelity of the Zheng. The study uses 12 tree species in both materials of straight and cross grains. Furthermore, they were tested through 2 methods of physical experiments and bridges practical making. The physical experiments gained the physical properties of materials. Frequency analyses of the bridge are comparing the acoustic fidelity with the real performance. The results appear the acoustic fidelity during the performance does not relate to the hardness and the density of wood directly, except for draw speed of stress waves via density and the modulus of elasticity （MOE）of static bend. The speed of stress waves faster presents higher in basso well but a speed lower unsatisfies in high-pitch voice easily. The characteristic of straight and cross grains shows differences in physical experiments. But the frequency analysis aspect in base frequencies strength of straight grains is higher than the cross grains in the low region. Other regions are not significantly. Most of the bridges of Zheng were made of narra (common name of Pterocarpus spp.). Though narra is good for overall acoustic frequency, it is not the best one among the 12 tree species for the acoustic fidelity in mid and high regions. Furthmore, the optimal test material is different in the 4 regions. Basso is Black bean, Michelia, Hard maple, Padauk and so on. Higher basso is Sepetir, Black bean, Hard maple. Mediant is White oak, Padauk and a high-pitch voice is Black bean, Michelia, Hard maple, Padauk. Therefore, bridges which are combined with the proper optional test material in each region produces optional acoustic fidelity in the playing are ideal ones. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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