Planar loudspeaker manifold for improved sound dispersion

Patent metadata

Field	Value
Publication number	US-10602263-B2
Application number	US-201716079300-A
Country	US
Kind code	B2
Filing date	Feb 22, 2017
Priority date	Feb 24, 2016
Publication date	Mar 24, 2020
Grant date	Mar 24, 2020

Abstract

An acoustic manifold for altering a sound wavefront shape from a loudspeaker having a substantially planar driver, comprising a mounting surface configured to attach to a front surface of a case surrounding the driver and having two vertical openings matching corresponding vertical openings in the case to allow sound from the driver to project therethrough, and a waveguide portion coupled to the mounting surface and having a structure channeling sound projected from the driver through the two vertical openings to be combined in one output area. The structure has a plurality of reflective surfaces configured to create output sound that has a consistent dispersion pattern over a defined area. The manifold is configured to increase a vertical and/or horizontal beamwidth of the projected sound so that listeners positioned off an axis of the loudspeaker will hear a wide range of audible frequencies at a substantially similar sound level.

First claim

What is claimed is:

1. A planar magnetic loudspeaker system having a substantially planar driver, a case surrounding the driver and having two case openings aligned with a long axis of the driver, and an apparatus for altering a sound wavefront shape from the planar driver, said apparatus comprising:
a mounting surface attached to a front surface of the case and having two openings matching said case openings to allow sound from the driver to project therethrough; and
a waveguide portion coupled to the mounting surface and having a structure configured to channel sound projected from the driver through the two openings to be combined in one output area,
wherein the structure has a plurality of reflective surfaces configured to create output sound that has a consistent dispersion pattern over a defined area, said reflective surfaces being formed from contours formed into said side walls to form sound transmission paths for any sound channeled through the two openings,
wherein the side walls are curved inward to form a narrower sound transmission area around a center of the loudspeaker and a wider sound transmission area around opposite ends of the loudspeaker, and
wherein the one output area comprises an outwardly flared sound output area forming a dispersion angle along a short axis of the loudspeaker of approximately 90 degrees.

2. The system of claim 1 wherein the structure comprises a manifold frame with two side walls and a central pillar running between the side walls to form said two openings and said one output area, and wherein said reflective surfaces are further formed into corresponding projections formed into said central pillar.

3. The system of claim 2 wherein the one output area comprises an outwardly angled waveguide, the angled waveguide comprising a compound flared structure having a series of flared openings each waveguide angles increased at each additional flaring element.

4. The system of claim 1 wherein the manifold structure is configured to increase at least one of a long-axis beamwidth or short-axis beamwidth of the projected sound so that listeners positioned off an axis of the loudspeaker will hear a wide range of frequencies at a substantially similar sound level, the range of frequencies comprising approximately 200 Hz to 20 kHz.

5. The system of claim 4 wherein a dispersion pattern of the output sound is one of:
symmetric about both the long axis and short axis of the loudspeaker or asymmetric about either or both of the long axis and short axis of the loudspeaker.

6. The system of claim 1 wherein the planar magnetic driver is a dipole planar magnetic driver configured to radiate sound through openings on opposite sides of the case, and wherein a manifold frame is coupled to each opposite side, and wherein a manifold frame coupled to one side is the same or different from the manifold frame coupled to the opposite side.

7. A method of increasing one or more dispersion angles of a planar magnetic loudspeaker having a substantially planar driver projecting sound through a case having two separate openings along the long axis of the driver, the method comprising:
directing the sound projected from the two openings into two entry columns of an acoustic manifold attached to a front surface of the case, said manifold having a frame structures to form two sound transmission paths;
channeling the sound through said two transmission paths of the two entry columns to combine and form a single sound output;
wherein the side walls are curved inward to form a narrower sound transmission area around a center of the loudspeaker and a wider sound transmission area around opposite ends of the loudspeaker; and
projecting the single sound output through a flared output area to create output sound that has a consistent dispersion pattern over a defined area, and having a dispersion angle of approximately 90 degrees.

8. The method of claim 7 , wherein the frame structures comprise two side walls and a central pillar running between the side walls to form said two entry columns and one output area, and reflective surfaces being formed from contours formed into said side walls and corresponding projections formed into said central pillar.

9. The method of claim 8 wherein the flared output area comprises an outwardly angled waveguide forming a dispersion angle along a short axis of the loudspeaker, and comprising a compound flared structure having a series of flared openings each waveguide angles increased at each additional flaring element.

10. The method of claim 7 wherein the manifold structure is configured to increase at least one of a long-axis beamwidth or short-axis beamwidth of the projected sound so that listeners positioned off an axis of the loudspeaker will hear a wide range of frequencies at a substantially similar sound level, the range of frequencies comprising approximately 200 Hz to 20 kHz.

11. The method of claim 10 wherein a dispersion pattern of the output sound is one of symmetric about both the long axis or short axis of the loudspeaker, and wherein the driver is one of a monopole speaker or a dipole speaker.

Assignees

• Dolby Laboratories Licensing Corp

Inventors

• Smithers Michael J
• Showalter Garth Norman

Classifications

• H04R9/063

  using a plurality of acoustic drivers (H04R1/24 and H04R1/403 take precedence) · CPC title

• G10K11/02

  Mechanical acoustic impedances; Impedance matching, e.g. by horns; Acoustic resonators · CPC title

• H04R9/048

  of the ribbon type · CPC title

• H04R9/025

  Magnetic circuit · CPC title

• H04R1/345 Primary

  for loudspeakers · CPC title