| 摘要 |
PURPOSE:To enable simplification of a positioning work of a microphone and the improvement in precision, by a method wherein a rotary arm provided with a microphone is driven by a drive source which can be controlled at each rotation angle. CONSTITUTION:A plurality of microphones are attached to an arm 13 formed in a quarter-circular arc so that they direct to the center of the circular arc, and the arm is secured to an output axis 12 of a step motor 11 which is hung down from a ceiling of a measuring chamber through a support member 15. An object 16 to be measured is placed on an center axis line right below the step motor 11. With the motor 11 running, the arm 13 is spun to draw a semispherical movement locus as indicated in a chain line l. Microphones 14 attached to the arm 13 draw movement loci m-Q... centering about the object 16 to be measured and within a space place surface to detect a sound pressure on the locus. A signal detected by each microphone 14 is supplied to a control system through a cable 17 to process it thereat. |
