In-situ sound insulation measurement when a room is very absorptive

Abstract

The sensitivity of the ASTM E336 to absorption in either the source or receiving room and its effect on the number of microphones needed to sample the resulting field was studied. Nine microphone positions satisfying the ASTM E336 location requirements sampled the SPL. The apparent transmission loss (ATL) was measured in both directions between the three possible room pairs: horizontally separated by a partition wall, vertically separated by a floor, and diagonally where there was no common element. The results indicate that measurements in rooms having absorption typical of furnished multifamily dwellings are possible if the room volumes are adequately sampled.