| 摘要 |
PROBLEM TO BE SOLVED: To provide an acoustic characteristic measurement device capable of easily and properly adjusting a gap between the inner peripheral surface of an acoustic tube and the outer peripheral surface of an object to be detected.SOLUTION: An acoustic characteristic measurement device provides a sound source speaker on one end of an acoustic tube storing an object to be detected of a measurement object, excites a plane wave inside the acoustic tube by the sound source speaker, measures a complex sound pressure transfer function between two lengthwise positions between the sound source speaker and the object to be detected by two measurement microphones, and can calculate an acoustic characteristic from this complex sound pressure transfer function. The acoustic tube is formed of first and second tubes which are mutually separable and connectable. A fastening ring for the object to be detected is provided inside the opening of the second tube. This fastening ring includes a split ring variable in the inner diameter, and the object to be detected is stored inside this split ring. The inner diameter of the split ring is reduced so that a gap between the inner peripheral surface of the split ring and the outer peripheral surface of the object to be detected is made adjustable. A gap quantity between the object to be detected and the storage part can be adjusted in a step-less manner, thereby realizing a stable acoustic characteristic measurement.SELECTED DRAWING: Figure 1 |
