Novel plenum window with sonic crystals for indoor noise control

Abstract

A novel plenum window with incorporation of sonic crystals (SCs) was investigated using numerical and experimental methods in the present studies. Additional insertion loss (IL) that could be obtained by the 3 SCs was computed through a commercial software and was validated through experimental results from reverberation rooms. Experimental data showed that the SCs could attenuate more traffic and construction noises compared to white noise. When the noise source directly faced the opening of the plenum window, the performances of the SCs in reduced traffic and construction noises were improved significantly especially at low and middle frequency ranges (from 250 Hz to 1250 Hz and from 800 Hz to 2500 Hz for traffic and construction noise, respectively), which covered the designed center and resonant frequencies of the SCs (1000 Hz and 1164 Hz, respectively). For such a case, the SCs were able to attenuate additional 4.2 dBA and 2.1 dBA of traffic and construction noises, respectively, at 1000 Hz. Peak IL was found to be at 630 Hz which was about 5.4 dBA and 5.5 dBA for traffic and construction noise, respectively.