Acoustic Performance of Soundproof Ventilation Units installed in Dwelling Walls
* Presenting author
Large number of houses in developing Asia countries are being affected by road traffic noise emission from motorcycles which create frequent klaxon sounds. On the other hand, the use of ventilation holes for providing healthy indoor air is commonly found in those countries. However, these ventilation holes also provide direct paths for traffic noise to enter a residence. This paper describes the design of the soundproof ventilation unit for installation inside the wall of a house. For this purpose, the rectangular cube or elliptic cylinder form is reasonable as the unit shape. The sound pressure propagating in the unit has a standing wave and higher-order mode wave components. The latter occurs in the high-frequency range. The Noise tends to increase in this frequency range due to higher order mode resonance. In this paper, at first, the theoretical calculations of the sound pressure inside the rectangular cube and elliptic cylinder are carried out by solving the wave equation. Next, the resonance frequencies of the higher-order mode wave component are calculated for rectangular cube and elliptic cylinder of the same volume. Some comparisons between the experimental results and the estimated ones by the proposed method are discussed.