US 2005/0087392 A1Published application

Loudspeaker enclosure

OwnerAndrew Flanders, Bradley Judah +1inventors

InventorsAndrew Flanders, Bradley Judah, Andrew Bartha

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Abstract

A loudspeaker enclosure is arranged to support at least one electromagnetic loudspeaker driver generating both front and back acoustic waves. The front of the speaker is substantially planar and the driver is mounted in an opening in the front of the enclosure to radiate forwardly. The driver's back wave communicates through a passage adapted to function as an impedance-matched transmission line cavity having a length that is, preferably, three times the driver cone's diameter, and having one or more ports terminating in openings defined in a plane that is, preferably, substantially perpendicular to the enclosure's planar front. The port or ports have a cross sectional area of, preferably 0.707 to 1.414 times the operative area of the driver cone, thereby giving a highly efficient means of sound propagation.

Claims20

Dependent claims

A loudspeaker enclosure adapted to support an electromechanical transducer or loudspeaker driver comprising, in combination:

(a) a hollow enclosure having front and rear walls intersected by first and second opposing side walls and first and second end walls joined at said intersections to define an enclosed volume,
(b) a first loudspeaker driver having a selected diaphragm diameter, a selected diaphragm surface area and an acoustic characteristic impedance and mounted on a selected one of said walls of said hollow enclosure in an opening sized to receive one side of said first loudspeaker driver, said wall being designated as a driver mounting baffle;
(c) said loudspeaker driver being configured to receive an electrical excitation signal and, in response, providing both front and back acoustic waves of audio frequencies, wherein said front acoustic wave is radiated outwardly into free space and said back acoustic wave is radiated inwardly into said enclosed volume;
(d) a port of a predetermined cross sectional area located in a wall opposing said driver mounting baffle, said port being in fluid communication with a transmission line path having a selected length and a selected cross sectional area over most of said length;
(e) said transmission line path having an inlet end proximate said first loudspeaker driver and configured to receive substantially all of said back acoustic wave, and having an outlet end defined by said port;
(f) said transmission line length being greater than two and one half times said first loudspeaker driver diaphragm's diameter;
and
(g) wherein said transmission line path is dimensioned to provide an acoustic characteristic impedance that substantially equals said first loudspeaker driver's acoustic characteristic impedance.

5 more elements

A loudspeaker enclosure adapted to support an electromechanical transducer or loudspeaker driver comprising, in combination:

(a) a hollow enclosure having a substantially planar front wall segment intersected by one or more side walls joined to define an enclosed volume,
(b) a first loudspeaker driver having a selected diaphragm diameter, a selected diaphragm surface area and a characteristic impedance and mounted on said front walls of said hollow enclosure in an opening sized to receive one side of said first loudspeaker driver;
(c) said loudspeaker driver being configured to receive an electrical excitation signal and, in response, providing both front and back acoustic waves of audio frequencies, wherein said front acoustic wave is radiated outwardly into free space and said back acoustic wave is radiated inwardly into said enclosed volume;
(d) a port of a predetermined cross sectional area located in a wall segment offset by at least ninety degrees from said planar front wall segment, said port being in fluid communication with a transmission line path having a selected length and a selected cross sectional area over most of said length;
(e) said transmission line path having an inlet proximate said first loudspeaker driver and configured with an angled reflective surface to direct substantially all of said back acoustic wave into an orthogonal direction with respect to said driver diaphragm, and having an outlet end defined by said port;
(f) said transmission line length being greater than two and one half times said first loudspeaker driver diaphragm's diameter;
(g) wherein the cross sectional area of said port equals an area that is greater than said first loudspeaker driver's diaphragm surface area multiplied by 0.707;
and
(h) wherein the cross sectional area of said port equals an area that is less than said first loudspeaker driver's diaphragm surface area multiplied by 1.414.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/939,112Filed 13 Sep 2004
Priority: 12 Sep 2003
Published: 28 Apr 2005
Term ends: Not estimatedThe source records don’t support an estimate.

Classification3 codes

H04R 1/2857
Using an acoustic labyrinth or a transmission line: for loudspeaker transducers
H04R 1/26
For obtaining desired frequency characteristic only: spatial arrangements of separate transducers responsive to two or more frequency ranges
H04R
Loudspeakers, microphones, gramophone pick-ups or like acoustic electromechanical transducers

Family

Application60/502,199Us provisional application · filed 12 Sep 2003
US 2005/0087392 A1This patent

From the US filing history. Foreign family members aren’t listed.

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