Reconstruction of the spatial radiation characteristics of large Korean bell

Abstract

The conventional recording of sounds radiating from a specific source provides limited information at the measurement positions and it is not possible to obtain the sound at other positions. Hence, an approach based on model construction is required to reproduce the sound at any arbitrary position, radiating from the source. In this study, the spatial radiation characteristics of the large Korean bell named "Divine Bell of King Seongdeok" were reconstructed using the near-field acoustic holography based on the equivalent source method. The "Divine Bell of King Seongdeok" is famous for its unique sound characteristics, including a beating sound produced by two dominant modes at close frequencies. It is also known that its radiation characteristics depend on the direction, even the main frequency component around 60 Hz. The measurement was conducted using 120 microphones in the near field, and the equivalent source model was constructed with a spherical radiation function. The directional dependency of the radiated sound field including the beating characteristics was accurately reproduced by this model through the superposition of each mode frequency.