Studies on Rolling Sound. 2nd Report, Effects of Distance of Measuring Microphone on Sound and Sound Radiation Characteristics.

Abstract

Rolling motion is one cause of mechanical sound. Rolling sound may cause serious problems when it is excessive in machines, structures, and the like. A series of studies have been carried out in order to obtain basic information for the reduction of rolling sound. This second report concerns the effect of the distance of the measuring microphone on the sound and the sound radiation characteristics. A horizontal square steel plate was simply supported at four points. Nylon and steel balls with different diameters were rolled at various rolling velocities on the plate, and the sound and the vibration of the plate were simultaneously measured using a condenser microphone and an accelerometer, respectively. The signals obtained in the measurements were analyzed with a FFT analyzer. From the experiments, analysis and considerations, the effects of the distance of the measuring microphone on the sound and the sound radiation characteristics were clarified.