IMPROVING THE LOW FREQUENCY SOUND TRANSMISSION LOSS OF DOUBLE-PANEL STRUCTURES WITH PERFORATED BALL SOUND ABSORBERS

摘要

A perforated ball sound absorber with extended tubes (PBETs) was designed to improve the low frequency sound transmission loss of the double-panel structures. First the sound absorbing performance of the PBETs was measured in the impedance tube. Then the measurement of the transmission loss of the double-panel structures with or without PBETs was conducted in the sound insulation testing room. The experiment results indicated that the sound transmission loss of the double-panel structures was improved 5dB at the target frequency by inserting the PBETs between them. The sound pressure level in the receiving room was reduced 9dB at the target frequency.