Broadband Nonreciprocal Acoustic Scattering Using a Loudspeaker with Asymmetric Feedback

This paper describes an acoustic system enabling us to achieve asymmetric transmission over a broad frequency range. The basic elements of the are moving coil loudspeaker placed along axis duct, and microphone flush mounted next front side loudspeaker. acts both as mass-spring oscillator through which incident waves reflected transmitted, sound re-emitter controlled by feedback loop. It is shown that reciprocity resulting two port broken, it can be used design broadband wave transmitter. experimental results show there exists band ranging from about 300 Hz up 1500 Hz, where almost perfect in forward direction observed whereas weak (i.e., 10%) achieved reverse direction. Owing broadbandness this efficient compact nonreciprocal scatterer, also its response pulses trap.