290 



ARCHITECTURAL ACOUSTICS 



The monitoring box is usually located in the rear balcony, the position 

 which is the most susceptible to the augmented sound and one which also 

 furnishes a good view of the action. 



D. Reverberation Time of a Theatre for the Reproduction of Sound. — The 

 optimum reverberation time of theatres for the reproduction or the re- 

 enforcement of sound as a function of the volume of the auditorium, for a 



FREQUENCY 



1000 

 CYCLES PEB SEC6ND 



10000 





 1000 



10000 100000 



VOLUME IN CUBIC FEET 



Fig. 12.6. Lower graph shows the optimum reverberation time for a theatre as a function 

 of the volume for 1000 cycles. Upper graph shows the relation between the reverberation 

 time and the frequency, that is, the reverberation time at other frequencies is obtained by 

 multiplying by K. 



frequency of 1000 cycles, is shown in the lower graph of Fig. 12.6. The 

 reverberation time for other frequencies can be obtained by multiplying by 

 the factor K, obtained from the upper graph of Fig. 12.6. The reverbera- 

 tion time increases at the lower and higher frequencies so that the aural 

 rate of decay of pure tones will be approximately the same for all frequen- 

 cies. See Sees. 13.4 and 13.5 and Figs. 13.1 and 13.2. 



E. Power Requirements for Reproducing Systems ^^. — The power require- 



13 Olson, H. F., RCA Review, Vol. 1, No. 1, p. 49, 1936. 



