基于分流电路调控的宽低频吸隔声机理研究

Considering the structure of loudspeaker with shunting circuits, a new mechanism was proposed to widen the frequency bandwidth of sound absorption and isolation based on the concept of adaptive modulation. Firstly, a suitable loudspeaker structure for broadband and low-frequency sound insulation was studied. The analysis result shows that, in the two-dimensional space parameterized by sound frequency and inductance in shunting circuits, there a trajectory with high sound transmission loss exists, being of advantage to determine a specific profile of the frequency-inductance relationship. According to the analysis result, a shunting circuit was designed, making the frequency-dependent inductance adaptively trace the high sound transmission loss trajectory. The practical experiment results show that, the sound insulation bandwidth can be significantly expanded in the low frequency region, and the bandwidth can be further broadened by combining the adaptive structures with different operating frequency. And then a suitable loudspeaker structure for sound absorption was also studied. The result shows that, there is a similar high sound absorption trajectory existing in the frequency-inductance parameter space. The absorption bandwidth can be broadened by designing a control circuit to adaptively trace the high sound absorption trajectory. Finally, combining an absorptive loudspeaker with micro-perforated plates, a composite structure was studied. The Simulation results show that, the sound absorption bandwidth can be further broadened due to the action of both adaptive circuits and small holes. The study achievement provide a new mechanism for widening the sound absorption and insulation bandwidth of the loudspeaker structure, and is potentially useful in noise control engineering.