317 



TABLE 310A.— OPTIMUM REVERBERATION TIME (FIGS. 4 AND 5) 



(concluded) 



2.2 



1.8 



1.6 



U 

 tO 1.4 



S 1.2 



1.0 



0.6 



0.6 



10 



20 30 40 50 60 SO lOO 200 300 400 500 70O lOOO 



VOLUME IN THOUSANDS OF CUBIC FEET 



Fig. 4. — Optimum reverberation time as a function of volume of rooms for various types of 

 sound for a frequency of about 512 cycles per second. 



1.4 



1.2 



*I.O 



oe 



lOO 200 300 400 600 800 lOOO 2000 3000 5000 10.000 



FREQUENCY IN CYCLES PER SECOND 



Fig. 5. — Ratio of the reverberation time for various frequencies as a function of the 

 reverberation for 512 cycles per second. 



SMITHSONIAN PHYSICAL TABLES 



