548 BELL SYSTEM TECHNICAL JOURNAL 



of Stress to dissipative component of strain rate; (2) hysteretic constant 

 defined as the area in ergs of the cycHc stress-strain diagram; and (3) 

 elastic phase constant defined as the ratio of specific elastic reactance 

 to equivalent viscosity. Within a range of frequencies 100 to 100,000 

 cycles per second the results show that the hysteretic constant is 

 proportional to some power A of the frequency, the numerical value of 

 the exponent A varying between the limits —}/^ and +3^, depending 

 on the kind of material and its internal structural condition. Meas- 

 urements made with longitudinal and torsional vibration indicate 

 that dissipation is associated with dilatation as well as with pure shear. 

 Preliminary studies are described showing the correlation between 

 internal dissipation in metals and temperature hardness effects of 

 annealing and aging. 



Broadcasting Studio Acoustics}^ S. K. Wolf and C. C. Potwin. It 

 is now of fundamental importance that studios be designed to provide 

 an acoustic transmission characteristic that will insure the fullest 

 benefits from the many recent improvements in transmitting and 

 receiving systems. For this reason, the traditional "dead" studio, 

 which was so common in the early days of radio, is no longer suited 

 to the present technique of broadcasting. 



This paper deals with improved methods of analysis and treatment, 

 particular consideration being given to the problems of the small 

 studio. A description of the high-speed level recorder, its operating 

 characteristics and application to studio analysis, are included. The 

 increased accuracy of instrumental measurement over computational 

 methods in the solution of the problems of reverberation, multiple 

 reflection and room resonance at various frequencies is explained. 

 The factors governing the proper selection and distribution of acoustic 

 materials are discussed and supported by actual measured data taken 

 with the level recorder in studios designed in accordance with the 

 methods advocated. 



Two typical studio designs are illustrated, one suggesting sound 

 reflective angular wall and ceiling surfaces adjacent to the performers, 

 a moderate sound absorbent on the intermediate surfaces and a highly 

 efficient absorbent on the surfaces adjacent to and surrounding the 

 microphone. Distant pickup employed in this type of studio is 

 briefly described. 



Quantitative Studies on the Singing Voice}^ S. K. Wolf, D. Stanley 

 and W. J. Sette. The field of singing has been handicapped by the 



^^ Communicalion and Broadcast En^ineerifig, April, 1935. 

 ^^ Jour. Acotis. Soc. Anier., April, 1935. 



