Unidirectional acoustic boundary through active control system in one dimensional duct

The unidirectional acoustic boundary has broad application prospects. Besides the strongly nonlinear acoustic medium, which can be applied in the realization of the unidirectional acoustic boundary, the present paper proposes a new approach through the active control method, where the secondary source has the property of single directivity. In order to validate its effectiveness in onedimensional duct, experiments are implemented in three steps: 1. construct the secondary source with the single directivity by two loudspeakers; 2. design the steady unidirectional acoustic boundary by the secondary source in step 1; 3. implement the adaptive unidirectional acoustic boundary by the secondary source in step 1, and through FXLMS algorithm. Results show that the presented approach is feasible and effective for one-dimensional unidirectional acoustic boundary, and the system only contains two traditional loudspeakers and two traditional microphones; thus it will be more feasible for practical realizations of the unidirectional acoustic boundary, compared with the acoustic diode.