Reverberation Time and Absorption Measurements with the High Speed Level Recorder
E. H. Bedell, Karl D. Swartzel · The Journal of the Acoustical Society of America · 1934
The high speed level recorder described by Messrs. Wente, Bedell and Swartzel may be used in many types of acoustical measurements. It is particularly well adapted to the measurement of reverberation time, however, because with a single interruption of the test tone a continuous curve of sound intensity during the decay period is obtained on a logarithmic scale. The level recorder has recently been modified so that measurements can be made through an intensity range as great as 90 db. This paper presents some data obtained with the level recorder on reverberation measurements in a sound chamber, and includes an investigation of the accuracy of the results as affected by the intensity range through which measurements are made, the use of rotating reflectors, warble tones, a number of loudspeaker and microphone positions, and a number of microphones simultaneously, placed at different locations in the chamber.