Cushman, Darby & Cushman
Acoustic reproducing apparatus
 The present invention relates to an acoustic reproducing apparatus which is suitable particularly for listening to reproduced sound with noise through an open-air-type head phone. A sound leakage frequency band, when a head phone is loaded is measured in advance, and operation of a filter attenuating that sound leakage frequency band is changed-over. Thereby the sound leakage from the head phone to the outside in the loaded state is controlled. Also, a noise frequency characteristic is measured in advance, the low frequency band is intensified so as to correspond to that characteristic, and operation of the filter for attenuating the high frequency band containing the above-mentioned sound leakage frequency band is controlled to be changed-over. 
Matsushita Electric Industrial Co., Ltd.
H
H04R
inventional
Kazutoshi Atsushi Koichi Eiichi Masataka
Yamaguchi Nagayoshi Higuchi Takakura Saito