308 



ARCHITECTURAL ACOUSTICS 



Mechanical transmission of sound by the ducts may be reduced by isolating 

 the sections of the duct. 



In the last few years, the live-end-dead-end principle has been modified 

 and uniform absorption throughout the studio is obtained by uniform dis- 

 tribution of the absorbing material. Serrated and " V " walls have been 

 used to break up discrete reflections. The use of treatments with com- 

 plementary absorption characteristics to obtain the proper absorption is 



10000 , 100000 



VOLUME IN CUBIC FEET 



Fig. 12.16. Lower graph shows the reverberation time for a recording or broadcasting 

 studio 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. (After Morris and Nixon.) 



usually preferable because of the latitude afforded in the decorative treat- 

 ment of the studio. 



C. Reverberation Time of a Broadcasting, Recording and Scoring Studio. 

 — The reverberation time of a studio is another important factor. The 

 reverberation time ^^ as a function of the volume of the studio for broad- 

 casting and phonograph recording is shown in Fig. 12.16. 



In the case of sound motion picture recording and television broadcasts 

 the setting is usually a room within a room. The sound stage is usually 



30 Morris and Nixon, Jour. Acous. Soc. Amer., Vol. 8, No. 2, p. 81, 1936. 



