Effects of varied row spacing and adding cushions, carpet and occupants on pew sound absorption

This work examines how the individual variations of row spacing, as well as the presence of cushions, carpet and occupants, combine to influence the absorption characteristics of church pews as a function of sample perimeter-to-area (P/A) ratios. Scale models were used to measure the interactive effects of the four test variables on church pew absorption characteristics. The effects of row spacing on frequency-averaged pew absorption coefficients (500–4 kHz) were generally quite small and were smallest for pews without cushions. The variations of absorption increments with varied row spacing tended to be smallest when the pews were less absorptive, i.e. with less cushions, carpet or occupants, similar to the previously studied model theatre chairs. Resonant absorption effects seem to influence the measured absorption of the model pews in the 125 and 250 Hz octave bands and these effects are expected to be modified by the height of the pew backs and the spacing between pews. The incremental absorption coefficients of adding absorptive materials, such as carpet or cushions, to the pews were different than the absorption characteristics of cushions or carpet tested independent of the pews, and these differences varied with frequency. Using the resulting absorption coefficients calculated for each block of pews in a church as input to a room acoustics computer model is expected to provide the best currently possible predictions of acoustical conditions.