ABSTRACTS OF TECHNICAL ARTICLES 481 



the Madison Square Garden, New York, N. Y., which revealed a 

 consideral)le discrepancy between theoretical expectations and the 

 times actually measured throughout the frequency range. At 500 

 cycles, for example, analysis of the auditorium indicated a decay 

 period of 35.5 seconds, whereas the time actually measured by the 

 spark chronograph reverberation meter was only 7.6 seconds. On the 

 basis of the measured time, 47,000 square feet of one-inch rock wool 

 were installed. This material was distributed in a manner calculated 

 to suppress undesirable discrete reflections as well as to reduce the 

 general reverberation time. The result was a reduction in the meas- 

 ured time to 3.5 seconds and the complete elimination of acoustic 

 difficulties. Present reverberation formulas do not possess sufficient 

 generality to justify application to enclosures which are extremely 

 atypical in size or shape. Until such formulas are developed, reliance 

 must be placed on actual measurements. 



