Effect of slit-shaped apertures on sound insulation performance of building elements

In this work, the sound transmission through various dimensions of slit-shaped apertures is investigated. Both laboratory measurements and theoretical predictions are considered. The lower part of a door without a doorsill is represented by 18 examples with different size slits. The sound transmission through the slit-shaped apertures was more dependent on the width than the depth of the slit. The weighted sound reduction index (SRI) was found to rapidly degrade as the slit width increased, and unfavorable deviations between the measured curve and the reference curve based on ISO 717-1 appeared mainly around the first resonance frequency of the slit. In terms of the weighted SRI, the values predicted by Gomperts' theory have a good one-to-one correspondence with the measured values and are accurate to within 2 dB (average 0.7 dB).