The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 12, 1976
Filed:
Mar. 04, 1975
Applicant:
Inventors:
Hisashi Yoshimura, Minoo, JA;
Yasutake Nishimura, Hirakata, JA;
Assignee:
Matsushita Electric Industrial Co., Ltd., Osaka, JA;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H04M / ; H04R / ;
U.S. Cl.
CPC ...
1791 / ; 179 / ;
Abstract
A structure of four-channel headphones having sound insulating means between front and rear channel driver units, and tone control means only for the front channel tones, said sound insulating means being formed of foam material which transmits low-pitched tones and absorbs high-pitched tones. Separation of the front and the rear channel tones is improved to closely resemble four-channel sound reproduction in a free field and the output levels of the medium-high range tones of the two front channels are made variable.