Title: Utilizing vector hydrophones to achieve an active anechoic terminal in an acoustic tube

Author(s): WANG Xiaolin; LIU Bilong; YANG Jun; LIU Jingwei; WANG Ran

Affiliation(s): Key Laboratory of Noise and Vibration Research, Institute of Acoustics, Chinese Academy of Sciences; University of Chinese Academy of Sciences; School of Mechanical Engineering, Qingdao University of Technology

Abstract: A new integrated active sound absorptive terminal using vector hydrophones is developed for the anechoic terminal of impedance tube, with which the reflected and the incident waves can be separated. The method overcomes the limitations imposed by the sensor spacing and measuring frequency range in the traditional two-hydrophone method, and can effectively expand low-frequency sound absorption band of the terminal. The effect of hydrophone sensitivity on the sound absorptive performance of the terminal is evaluated, a correction method is also provided for the reflection and transmission coefficient. The experimental results show that the absorption coefficient in the frequency band of 0.1-2 kHz is over 0.98,which agrees well with the theoretical results.