Abstract
Acoustic property of a series-coupled resonant chamber is studied. The chamber has two rectangular cavities and two slit-shaped necks in series. The impedance of the end surface of the second cavity is changed from that of a rigid wall to those of soft polyvinyl chloride sheets with several thicknesses. The reflection coefficient of the chamber for the normal incidence of the plane wave is measured using an acoustic tube. The lower impedance of the end surface makes the resonant frequencies higher and the resonant effects larger, especially for the first resonance. An analytical model for BEM (boundary element method) calculation is composed for simulating the experimental model of the chamber. The measured impedance of the end surface is applied to the BEM model. Although the absorption effect of the necks is ignored, the resonant frequencies are moderately predicted by the BEM calculation. For the prediction of the resonant effect, however, the acoustic property of the necks should be considered.
