| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an acoustic equipment, such as a mobile phone, enabling only a user to listen to sound at a prescribed distance without causing annoyance to people nearby. <P>SOLUTION: An audible region acoustic wave in high-directivity acoustic waves output by a parametric speaker 110 is cancelled by a cancelling acoustic wave output by a cancelling speaker 130. As a result, the range of audible region acoustic waves demodulated from the high-directivity acoustic waves output by the parametric speaker 110 can be limited and, for instance, audible region acoustic waves can be listened to at a prescribed distance so as not to cause annoyance to people nearby. <P>COPYRIGHT: (C)2012,JPO&INPIT |
