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. 18, 2005
Filed:
Jan. 24, 2005
Erik Thorsell, San Pedro, CA (US);
Glenn Cass, Lomita, CA (US);
Tetsuya Oishi, Iwaki, JP;
Alpine Electronics, Inc., Tokyo, JP;
Abstract
The invention provides a speaker unit for low frequency reproduction wherein distortion is reduced and the orientation of a sound image of the lower side frequency region is augmented. To that end, the phase characteristic in an actually used frequency band is made substantially flat. The speaker unit includes a speaker enclosure, a duct formed in the speaker enclosure and having a port thereon, and a speaker mounted in the speaker enclosure. The speaker is formed such that it has a first resonance frequency set higher than a higher side frequency of the actually used frequency band (about 20 Hz to 100 Hz), while the port is formed such that it has a second resonance frequency set lower than a lower side frequency of the actually used frequency band. For example, the speaker includes a vibrating system having a reduced mass or a reduced compliance with which the first resonance frequency is set higher than the higher side frequency of the actually used frequency band, and the duct has an increased length or a controlled cross sectional area with which the second resonance frequency is set lower than the lower side frequency of the actually used frequency band.