Patent ID: 6411721
Filing Date: 2002-06-25
Classification: H04R

Abstract:
A speaker system for use in an audio system to reproduce low frequency sounds, said speaker system comprising:a low frequency transducer for reproducing sounds in a low frequency band; a filter for blocking signals to said transducer that are higher than about 150 hertz in frequency; and an elongate linear enclosure defining an interior duct having first and second ends, said low frequency transducer being acoustically mounted in said enclosure with a front vibrating surface facing exteriorly of said enclosure toward said first end and a rear vibrating surface facing said interior duct, said first end having an opening therein adapted to allow sound produced by the front vibrating surface of said transducer to pass therethrough, said second end having an opening therein adapted to allow sound produced by the rear vibrating surface of said transducer to pass therethrough, the acoustic length of said duct being approximately one-eighth the length of the wavelength of the lowest frequency sound to be produced by said low frequency transducer; said interior duct being substantially open to thereby permit the low frequency acoustic waves produced by said vibrating surfaces to pass through said interior duct and said openings substantially unattenuated and undelayed.