Abstract
Relation between sound absorption power and vibrational modes of the micro-perforated thin aluminum plate, which is set with air space in a cylindrical enclosure, is studied. The sound field in that enclosure is excited by a speaker set at the one end, and vibration displacement over the thin plate is measured by laser displacement meter through glass plate set at the other end. Sound absorption coefficient of the perforated plate is also measured by two microphones method with and without dumping. Those results show that vibarational modes affect the sound absorption power, that calculation with the assumption of no vibration is not always suitable and that dumping is effective to prevent steep depression of sound absorption coefficient by resonant vibration.
