The reduction of the reverberation using the sound-absorbing metamaterial in the conference rooms

Abstract

Sound-absorbing metamaterial, iwasemi consists of multiple perforated Fabry-Perot resonators which have different resonant frequencies reciprocally to achieve broadband sound absorption coefficient. We have installed acoustic panels that are optimized for the main band of human voices, 1/3 octave band center frequencies from 500 Hz to 1000 Hz, in some conference rooms and measured the reverberation time of the rooms before and after installation. The measurement result shows that the acoustic panels have decreased the reverberation time of the rooms dynamically in the target frequency band (e.g. a case of we measured, the reverberation time reduced from 1.11 seconds to 0.66 seconds at 500 Hz octave band center frequency). As shown above, it has been indicated that installing plastic acoustic panels using acoustic metamaterial improves the acoustic environment in the rooms.