The design of small reverberation chambers for transmission loss measurement

Assessment of an acoustic chamber for testing structure-borne sound transmission in a double-panel assembly

“…The only other requirement necessary to set up a complete test facility for transmission loss measurement is the choice of the receiving chamber. The test facility could either incorporate a twin arrangement of reverberation chambers or a reverberation chamber coupled with either a full/hemi-anechoic chamber or a free-field chamber [29,31]. The reverberation room method is ideal for testing large structural assemblies and it is recommended that the test specimen should preferably form a whole room surface, wall or floor [35].…”

“…The design and construction of the reverberation room make it an expensive capital investment for a research institution. Whenever possible, a smaller reverberation chamber is used, where the only major drawback is its high cut-off frequency [31]. 17 Sound absorption testing determines the amount of sound absorbed by a material.…”

“…The sound absorption tests were conducted according to the suggestions given in ASTM C423-08a [24], except that the reverberation times of each room were determined from the decay curves of impulse excitation obtained using a Sound Analyzer software package that was based on ISO 3382 31 . The absorption of the room and its contents was calculated from the Sabine formula which was introduced in equation (3.1).…”

“…The volume of the acoustic chamber (source room) and that the laboratory (receiving room) are 0.488 and 121.8 m 3 , respectively. With these volumes, the 31 ISO 3382 is a standard for acoustics measurement of the reverberation time of rooms with reference to other acoustical parameters room absorption should not fall above 0.620 m 2 Sabine in the chamber and 24.57 m 2 Sabine in the laboratory, except above 2000 Hz where atmospheric absorption may make it impossible to avoid a slightly higher value than those calculated from equation (5.1). Reverberation time measurements obtained in a typical room are known to have little significance below 200 Hz as they are affected by the energy build-up of room modes.…”

Low-Cost and Portable Sound Reduction Box: Innovation for Acoustic Material Performance Measurement

“…The accurate assessment of the sound insulation properties of panels and partitions is an important area in acoustics [3]. The sound reduction index (RIc) of partitions is used to qualify a considerable range of structures, from fuselage panels to building elements [4].…”