PORTABLE ACOUSTIC EQUIPMENT

PROBLEM TO BE SOLVED: To provide portable acoustic equipment which is used by pressing it to an ear, in which a minimum resonance frequency of a vibration system, namely, an acoustic conversion element is dropped and a frequency characteristic with little characteristic change can be given without depending on a condition of coupling. SOLUTION: A hole for releasing sound 3 is made in a front wall 61 of a casing 6 in portable acoustic equipment. The acoustic conversion element 1 is supported and fixed in the casing so that a front air chamber 2 is formed with the front wall 61 and a back air chamber 4 is formed with a back wall 62 of the casing 6. Minimum inner width W of an outer fence 63 at a periphery of the casing 6 is set to be not more than a standard diameter of cavity of concha part of a person. A duct 5 to an outer part of the casing, which is a periphery of the hole for releasing sound 3, is installed in the front wall 61. COPYRIGHT: (C)2004,JPO&NCIPI