Reflective loudspeaker array

• US 7,684,574 B2
• Filed: 03/08/2006
• Issued: 03/23/2010
• Est. Priority Date: 05/27/2003
• Status: Active Grant

• Current Assignee: Harman International Industries Incorporated (Samsung Electronics Co. Ltd.)
• Original Assignee: Harman International Industries Incorporated (Samsung Electronics Co. Ltd.)
• Inventors: Button, Douglas J., Keele, D. Broadus Jr.
• Primary Examiner(s): Chin; Vivian
• Assistant Examiner(s): Monikang; George C
• Application Number:
  US11/371,538
• Publication Number:
  US 20060153407A1
• Time in Patent Office: 1,476 Days
• Field of Search: 381/335, 381/336, 381/337, 381/339, 381/350, 381/352, 381/160, 381/187, 381/189, 381/191, 381/199, 381 17- 19, 381/307, 381/310, 381/182, 181/187, 181/189, 181/191, 181/199
• US Class Current: 381/160
• CPC Class Codes: H04R 1/403 loud-speakers

Abstract

A reflective loudspeaker array is cooperatively operable with an acoustically reflective planar surface to provide a constructive combination of direct and reflected sound waves that produces a uniform sound field. The uniform sound field provides a controlled sound field in the vertical and horizontal direction, and also provides uniformity from distances close to the reflective loudspeaker array to far way. The direct and reflected sound waves are advantageously and constructively combinable to generate a focused beamwidth of soundwaves. The reflective loudspeaker array includes a plurality of loudspeakers coupled to a surface of the reflective loudspeaker array. The surface may be formed to include at least one curve with a radius of curvature. The reflective loudspeaker array may be placed adjacent an acoustically reflective planar surface such that a frontal plane of a loudspeaker adjacently located closest to the acoustically reflective planar surface is aligned perpendicularly, and a frontal plane of a loudspeaker spaced away from the acoustically reflective planar surface is not aligned perpendicularly.

Claims

1. A reflective loudspeaker array comprising:

a frame that includes a curved surface longitudinally extending between a first end and a second end of the frame, where the first end is operable to be positioned near an acoustically reflective planar surface;

at least five loudspeakers adjacently disposed in the frame so that at least a portion of the at least five loudspeakers are disposed in the curved surface, where a sound emitting surface of each of the at least five loudspeakers comprises a frontal plane, each of the at least five loudspeakers configured to receive a respective audio signal;

a first of the at least five loudspeakers disposed nearest the first end of the frame, where the frontal plane of the first of the at least five loudspeakers is positioned substantially perpendicular to the acoustically reflective planar surface when the first end is aligned with the acoustically reflective planar surface;

a second of the at least five loudspeakers disposed proximate the second end of the frame, where the frontal plane of the second of the at least five loudspeakers is non linear with respect to the frontal plane of the first of the at least five loudspeakers, and a magnitude of the respective audio signal received by the first of the at least five loudspeakers is greater than a magnitude of the respective audio signal received by the second of the at least five loudspeakers; and

the at least five loudspeakers operable to generate a direct sound wave, a portion of which is reflected with the acoustically reflective planar surface to form a reflected sound wave, and all of the reflected sound wave is constructively combined with the direct sound wave.

2. The reflective loudspeaker array of claim 1, where the at least five loudspeakers are disposed in the frame to be concentric with a common axis.

3. The reflective loudspeaker array of claim 1, where the curved surface is curved with a constant radius of curvature.

4. The reflective loudspeaker array of claim 1, where the first end includes a substantially flat surface that is alignable substantially in parallel with the acoustically reflective planar surface.

5. The reflective loudspeaker array of claim 4, where the substantially flat surface is positionable to be contiguous with the acoustically reflective planar surface.

6. The reflective loudspeaker array of claim 1, where the acoustically reflective planar surface is a substantially flat surface extending a length in a first direction that is at least the length of the frame between the first end and the second end.

7. The reflective loudspeaker array of claim 1, where the frame comprises a first portion that includes a first surface curved at a first constant radius of curvature, and a second portion with a second surface curved with a second constant radius of curvature that is different than the first constant radius of curvature.

8. The reflective loudspeaker array of claim 1, where the frontal plane of the second of the at least five loudspeakers forms an angle with the acoustically reflective planar surface that is less than 90 degrees.

9. A reflective loudspeaker array comprising:

a housing comprising a base that is configured to be positioned adjacent to an acoustically reflective planar surface so that the housing outwardly extends away from the acoustically reflective planar surface in a direction; and

at least five loudspeakers disposed adjacently on a surface of the housing, where at least a portion of the surface is curved at a radius of curvature, and where each of the at least five loudspeakers includes a frontal plane that is substantially parallel to at least a portion of the surface of the housing;

where each of the at least five loudspeakers are operable to be driven by a respective audio signal to generate direct sound waves, and part of said direct sound waves are reflected with said acoustically reflective planar surface as reflected sound waves; and

where the reflected sound waves are a mirror image of the direct sound waves and are constructively combined with the direct sound waves to produce an acoustic image.

10. The reflective loudspeaker array of claim 9, where the mirror image outwardly extends away from said acoustically reflective planar surface in another direction opposite the direction that the housing extends.

11. The reflective loudspeaker array of claim 9, where the frontal plane of each of a first loudspeaker and a second loudspeaker of the at least five loudspeakers are substantially parallel with respect to each other, and where the frontal plane of each of a third loudspeaker and a fourth loudspeaker of the at least five loudspeakers form an angle greater than five degrees with respect to each other.

12. The reflective loudspeaker array of claim 9, where the base includes a surface that is contiguously alignable in parallel with the acoustically reflective planar surface.

13. The reflective loudspeaker array of claim 9, where the radius of curvature is a constant radius of curvature.

14. The reflective loudspeaker array of claim 9, where the at least five loudspeakers are concentrically aligned on the surface to have a common central axis.

15. The reflective loudspeaker array of claim 9, where the frontal plane of a first of the at least five loudspeakers is positionable nearest the acoustically reflective planar surface and substantially perpendicular thereto.

16. The reflective loudspeaker array of claim 9, where the acoustically reflective planar surface is a substantially flat surface extending away from the base in all directions to one or more distances that are all equal to or greater than a length that the frame extends away from the acoustically reflective planar surface.

17. A reflective loudspeaker array comprising:

a plurality of loudspeakers operable to be driven by a corresponding plurality of audio signals;

a channel on which each of the loudspeakers are mounted such that a first of the loudspeakers is nearest a first end of the channel and a second of the loudspeakers is nearest a second end of the channel; and

a base included at the first end, where the base is formed to align the frame substantially perpendicular to a sound reflective planar surface;

where the first loudspeaker is operable to emit a sound wave in response to being driven by a corresponding first audio signal, where a magnitude of the first audio signal is greater than a second audio signal operable to drive the second of the loudspeakers; and

where a magnitude of the corresponding audio signals provided to the corresponding loudspeakers sequentially increase in magnitude from the second end toward the first end.

18. The reflective loudspeaker array of claim 17, where a frontal plane of the first of the loudspeakers is aligned to be substantially perpendicular to the planar surface when the base is aligned to be substantially parallel with the planar surface.

19. The reflective loudspeaker array of claim 17, where a first group of the loudspeakers are aligned linearly in a first direction on the frame surface, and a second group of loudspeakers are aligned linearly in a second direction on the frame surface that is perpendicular to the first direction.

20. The reflective loudspeaker array of claim 17, where the frame comprises a plurality of sub frames that are movable coupled to allow movement of the loudspeakers mounted thereon.

21. The reflective loudspeaker array of claim 17, where the frame comprises a plurality of subframes coupled by a plurality of linkages to be pivotally moveable with respect to adjacently coupled subframes, where at least one of the loudspeakers is mounted on each of the subframes.

22. The reflective loudspeaker array of claim 21, where each of the subframes are pivotally moveable with respect to at least two subframes coupled by linkages thereto.

23. A reflective loudspeaker array comprising:

at least five loudspeakers operable to be driven with respective audio signals;

a rigid frame formed with a frame surface that is at least partially curved with a constant radius of curvature, where the rigid frame includes a first end having a substantially flat surface that is alignable in parallel with an acoustically reflective planar surface, and where the frame further includes a second end maintainable in free air spaced away from the acoustically reflective planar surface;

where each of the at least five loudspeakers include an acoustic sound emitting surface that forms a frontal plane; and

where the at least five loudspeakers are mounted in the frame surface so that the frontal plane of each of the at least five loudspeakers are substantially parallel with the frame surface; and

where a first of the at least five loudspeakers is positioned nearest the first end so that the frontal plane of the first of the at least five loudspeakers is positioned substantially perpendicular with the acoustically reflective planar surface when the flat surface is substantially parallel with the acoustically reflective planar surface; and

where another of the at least five loudspeakers is positioned nearest the second end, and a magnitude of the respective audio signals operable to drive the respective loudspeakers is increased from the another of the at least five loudspeakers toward the one of the at least five loudspeakers.

24. A method of generating a sound field with a reflective loudspeaker array, the method comprising:

providing at least five loudspeakers mounted on a surface of a frame having a radius of curvature;

positioning a first end of the frame adjacent a planar surface that is acoustically reflective so that a second end of the frame is positioned away from the planar surface;

driving the at least five loudspeakers with respective audio signals to produce direct sound waves;

reflecting a portion of the direct sound waves as reflected sound waves with the planar surface;

constructively combining all of the reflected sound waves with the direct sound waves; and

generating an acoustic image representative of the direct sound waves and a mirror image of the direct sound waves.

25. The method of claim 24, where driving the at least five loudspeakers comprises driving a first loudspeaker positioned nearest the planar surface with a first audio signal and driving a second loudspeaker positioned farthest from the planar surface with a second audio signal, where a magnitude of the first audio signal is greater than a magnitude of the second audio signal.

26. The method of claim 24, where positioning a first end of the frame comprises positioning the first end of the frame so that a frontal plane of a first one of the at least five loudspeakers nearest the first end is substantially perpendicular with the planar surface, and a frontal plane of a second of the at least five loudspeakers forms an angle with the planar surface of less than ninety degrees.

27. The method of claim 24, where generating an acoustic image comprises doubling an effective height of the frame.

28. The method of claim 24, where generating an acoustic image comprises doubling a sound pressure output capability of the at least five loudspeakers.

29. The method of claim 24, where generating an acoustic image comprises doubling a sensitivity of the at least five loudspeakers.

30. The method of claim 24, where generating an acoustic image comprises extending a vertical coverage of a frequency bandwidth of the direct sound waves downward by an octave.

31. The method of claim 24, further comprising articulating the frame horizontally to adjust a horizontal coverage pattern of the generated acoustic image.

32. The method of claim 24, further comprising articulating the frame vertically to adjust the angle of curvature and a vertical coverage pattern of the generated acoustic image.