A kind of unidirectional secondary source is presented, which requires only one power amplifier and is made up of two loudspeakers and a special phase shifter.The structure of the phase ...

• 最后分别研制了高频和低频两套管道有源消声器.；实验结果表明；整套装置的消声效果好；构造简单；显著地降低了成本；因而有利于在实践中推广使用