Sound absorption of stretched ceilings with an impervious synthetic membrane

The sound absorption of stretched ceilings consisting of an impervious PVC membrane is investigated. A theoretical model is used to predict the random incidence sound absorption, and results are compared with the results of a n experimental setup in a reverberation chamber. The sound absorption coeff icient is estimated using a general model for the acoustic transmission and absorption of a multi-layered structure. Measurements have been performed for several cavity depths, and for two different sound absorbing materials in the cavity. Both theory and experiment showed that the combination of th e impervious foil and the cavity behaves as a resonant system. The sound ab sorption varies strongly with frequency and is highly dependent on the char acteristics and the position of the sound absorbing material in the cavity. (C) 1999 Acoustical Society of America. [S0001-4966(99)03307-X].