频率可调分流扬声器实验研究

分流扬声器是一种将声能转化为机械能进而转化为电能，最后以热能的形式耗散的新型共振吸声体结构，合理设计分流电路参数就可得到分流扬声器所需的固有频率。为了实现分流扬声器固有频率可调，文中提出了电感与负电阻电路串联的分流电路。实验结果表明，在通过负电阻电路抵消扬声器本身内阻后，扬声器固有频率随着电感值的增大而减小，可调范围介于开路与电阻趋于0且不加电感时的频率(98~278 Hz)；将分流扬声器应用于管道噪声控制，当分流扬声器的固有频率与管道声模态匹配时，相应声压级可以降低8~10 dB。

Research on adjustable sound absorption of shunt loudspeaker

Shunt loudspeaker is a new resonant sound-absorbing structure which converts sound energy into mechanical energy and then into electrical energy to dissipate finally in the form of heat energy. Reasonable design of shunt circuit parameters can obtain the desired sound absorption frequency. In order to realize the adjustable natural frequency of loudspeaker, a shunt circuit with negative resistance circuit and inductance circuit in series is proposed in this paper. The experimental results show that the natural frequency of shunt loudspeaker decreases with the increase of inductance when the internal resistance of loudspeaker is offset by negative resistance circuit, and the adjustable range is between the frequency of open circuit and the frequency when resistance approaches 0 and no inductance is added, that is 98-278 Hz; When the natural frequency of the shunt loudspeaker is matched with the sound mode of the pipeline, the corresponding sound pressure level can be reduced by 8-10 dB.