抄録
Parametric array loudspeaker (PAL) produces a highly directional sound beam due to the attribute of ultrasound used for carrier waves. Active noise control system with PAL has merit because it less causes spillover than that with normal loudspeaker. However, PAL still have serious problem in its sound quality because of harmonics. To solve this demerit, this paper propose a method using a adaptive filter to decrease harmonics sound pressure. In spite of simple process, we obtained good results by three cases experiment. These experimental date show this system is superior to conventional method such as Single-Sideband modulation (SSB) from two points of view. First, this system can control sound pressure both of the 2nd harmonics and intermodulation distortion. Second, the control effect is obtained on wide area with only a microphone.
