• The Journal of the Acoustical Society of Korea
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• v.31 no.5
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• pp.288-297
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• 2012

This study proposes a design model of the variable type resonator which corrects the temperature variance according to the season, in order to maximize the resonance effect in the Sacred bell of the Great King Seongdeok. In the bell, the 1st natural frequency (64 Hz) and the 2nd natural frequency (168 Hz) are the most important partial tones. Resonance conditions of the two components are determined for the internal acoustic cavity system, which consists of bell body cavity, gap and the resonator. Acoustic frequency response characteristics of the internal cavity are determined by the boundary element analysis using SYSNOISE. As an external factor, temperature variance according to the season largely influences the resonance condition and the length of the resonator should be controlled to maximize the resonance effect. As a measure, this study proposes a design model of the variable type resonator for the Sacred Bell of the Great King Seongdeok, which can control the length at the belfry according to the season.

• The Journal of the Acoustical Society of Korea
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• v.30 no.4
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• pp.223-230
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• 2011

Korean bell is hung with some air gap between the bell bottom and the ground. In addition, it has a peculiar acoustic element, so called resonance cavity below the bell. A proper design of the air gap and cavity size dramatically amplifies the bell sound by resonance effect. Bell interior cavity, air gap and resonance cavity consist of an acoustic cavity system. When the acoustic cavity frequency coincides with the natural frequency of the bell body, the frequency component is significantly amplified. On the Sacred Bell of the Great King Seongdeok, this study proposes a resonance condition of the cavity system considering air gap effect for the first time. With the exact dimension of the bell, boundary element analysis is performed using SYSNOISE. Finally, this study reveals how the temperature in season influences the resonance condition and proposes a concept of variable type resonance cavity. By using the variable type resonance cavity, the cavity size is controlled on site and exact resonance is available regardless of temperature difference in season.