수음실 음장 보정을 위한 잔향시간 측정시 음원의 지향 특성 및 위치의 영향

Abstract

To measure the air-borne sound and floor impact sound insulation performance, the sound field correction of the receiving room was conducted using reverberation time. Reverberation time is varied by environmental conditions, characteristics of sound source, position of sound source and microphones, etc. The sound field correction method on a rubber ball impact sound was standardized. In this study, the reverberation time was measured and compared using an omni-directional loud-speaker, a half-omni-directional loud-speaker, and a sub-woofer. Reverberation times at below 500 Hz bands became shorter when the height of the Omni-directional loud-speaker was increased. The reverberation times measured with the omni-directional loud-speaker at 1.7 m height were similar with the reverberation times measured with the half-omni-directional loud-speaker. For the measurement of reverberation time in low frequency below 80 Hz band, sub-woofer was installed on the floor. Reverberation times measured with sub-woofer were shorter than reverberation times measured using the half omni-directional loud-speaker, and the deviation was smaller. In order to make a correction for the receiving room sound field condition on light-weight impact sound, the height of the omni-directional loud-speaker should be approximately 1.7 m. In addition, for the sound field correction of the rubber ball impact sound at below 100 Hz bands, the use of sub-woofer for sufficient generation of sound energy in the low-frequency band is needed.