The Open Acoustics Journal

2014, 7 : 1-7
Published online 2014 December 31. DOI: 10.2174/1874837601407010001
Publisher ID: TOACOJ-7-1

Investigation of the Inlet and Outlet Location on the Soundproofing Ventilation Unit

Nasu Tsunetoshi and Nishimura Tsuyoshi
4-22-1 Ikeda, Nishi-ku, Kumamoto 860-082, Sojo University, Japan.

ABSTRACT

This paper deals with A-type and B-type rectangular cuboid SVU (soundproofing ventilation unit) contain an inlet and outlet in opposite surfaces. The difference between them is whether they are located in small or big cross section area. Following the theoretical calculation, the shape and location of the inlet and the outlet are determined by an investigation of the distribution of higher order mode waves formed inside the SVU. Finally, experimental results of Atype and B-type based on the reverberation chamber method are shown to be in reasonable agreement with our theoretical predictions. The results of theoretical calculation and experiments conducted lead to the conclusion that A-type is suitable for soundproof ventilation unit.

Keywords:

Higher order mode, resonance frequency, soundproofing, wave equation.