Sound Absorption Qualities of a Cross-Shaped Isolated Acoustic Resonator

In the paper, the sound absorption qualities of cross-shaped isolated acoustic resonator are considered. The sound absorption area of the resonator and the real and imaginary parts of the slit impedance, when the slit width varies from 20 cm to 60 cm, were computed from the formulas obtained by us.

It has been found experimentally that when the slit of the cross-shaped resonator is 30 cm wide and 60 cm deep, the maximal sound absorption coefficient is reached under 200 Hz and is equal to 0.2, while the absorption is 2 m². After the increase of the resonator slit depth to 180 cm, the maximal absorption coefficient is obtained at 160 Hz and is equal to 0.4, the absorption area being 9 m². In both cases the reverberation times are equal and come out to about 0.1 s.