Acoustical Design and Treatment for Speech Broadcast Studios

Three small speech studios have recently been completed by WOR in New York City. The factors taken into consideration are: (1) the reverberation time, (2) the shape of the reverberation-time-versus-frequency curve, and (3) the reduction of the standing sound waves in the studio. This paper describes how a studio designed for good music conditions will not give the best conditions for speech; particularly speech of the news broadcast type. By lowering the reverberation time at the low frequencies and allowing it to rise at the high frequencies, the effect is achieved of making the speaker in the studio sound as though he were actually in the home where he is being heard. The types of materials used in correcting broadcast studios are described. Graphs of the calculated time-frequency curves and as determined with a high-speed level recorder are shown. This paper explains the method of testing with the high-speed level recorder and also the discrepancies which occur between the caclulated and actual graphs. It explains the method by which the standing waves in the room are broken up to such an extent as not to be objectionable.