The Journal of the Acoustical Society of America · 1950 · 199 citations · 0 references
Natural SciencesPhysicsAcousticsBuilding PhysicsBuilding StructuresAcoustic MaterialsAcoustic PerformanceArchitectural AcousticsBuilding AcousticsRoom AcousticsSound TransmissionAbsorbent MaterialsAcoustic ImpedanceDissipationReactance TheoryRoom Acoustics ModelingSound Transmission Through WallsTransmission Loss PredictionTransmission Loss Reduction
Previous work examined reverberant sound transmission through homogeneous single walls both theoretically and experimentally. This paper applies the same technique to study sound transmission through a double wall composed of two identical single walls. The authors computed the average transmission loss of a double wall by integrating oblique plane‑wave attenuation over all incidence angles, using wall‑impedance expressions derived from single‑wall experiments for materials such as aluminum, plywood, and plasterboard, and applying these in the double‑wall theory. Theoretical predictions of double‑wall transmission loss closely matched experimental measurements.
In a previous communication the transmission of reverberant sound through homogeneous single walls was investigated theoretically and experimentally. The attenuation of an obliquely incident plane sound wave upon transmission through a single wall was computed and using the customary reverberant sound field statistics the attenuation was integrated over all angles of incidence to give the average transmission loss. A similar technique is employed in this paper in studying the transmission of sound through a double wall consisting of two identical single walls. The materials comprising the double walls are the same as was used in the single walls, i.e., aluminum, plywood, and plasterboard. From the single wall experimental results, an expression for the wall impedance, Zw, for each material, was determined, this expression containing terms which include the effects of the mass, dissipation or resistance, and flexural motion of the wall. This value of Zw is used in the double wall theory to compute the transmission loss for a double wall. Good agreement was obtained between theory and experiment.