Active control of a sound field with a state feedback electro-acoustic transducer

T. Samejima, D. Yamamoto

Research output: Contribution to journalArticlepeer-review


This study presents an alternative control system in which the acoustic impedance of the diaphragm of an electro-acoustic transducer can be manipulated by modifying the design parameters of the control system. This system involves a state-space description of an electro-acoustic transducer that is derived from its electrical equivalent circuit using modern control theory. The optimal quadratic regulator was used in the control system design, and the quadratic performance index was formulated to relate to the square of the sound pressure near the diaphragm of the control system. Computer simulations were performed to test the proposed control system and indicated that significant reductions in the acoustic impedance density could be achieved near the assumed vibration frequency that was used in the formulation of the quadratic performance index. A computer model of the proposed control system was used to illustrate effective active noise control in a duct and indicated that the control system brings about an effect similar to that of a resonator type muffler.

Original languageEnglish
Pages (from-to)135-140
Number of pages6
JournalAcoustical Science and Technology
Issue number2
Publication statusPublished - 2001

All Science Journal Classification (ASJC) codes

  • Acoustics and Ultrasonics


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