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:
Sep. 04, 1990
Filed:
Mar. 30, 1989
Kazunari Furukawa, Hamamatsu, JP;
Yamaha Corporation, Hamamatsu, JP;
Abstract
Disclosed is a compact, wide-range acoustic apparatus which can perform lower bass sound reproduction and is free from noise or distortion components. Spatially separated first and second chambers are formed. The first and second chambers communicate with each other through a port, so that the first chamber and a resonance port constitute a Helmholtz resonator. An open port is formed in or a passive vibrating body is arranged on the outer wall surface of the second chamber, so that the second chamber and the opening or the passive vibrating body constitute an essential low-pass type acoustic filter. A vibrator is attached to the outer wall surface of the first chamber, so that the Helmholtz resonator is driven at the inner surface side of the vibrating body of the vibrator, and an acoustic radiation is directly performed from its outer surface side. The vibrator is driven to cancel an air counteraction from the resonator when the Helmholtz resonator is driven. A cutoff frequency of the acoustic filter is set to be higher than a resonance frequency of the Helmholtz resonator and to be lower than the open duct resonance frequency of the resonance port.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile