2-way pseudo point source wide-diffusion speaker

Abstract

To provide a speaker system that allows sound to be perceived as being directed outward from an apparent point source.SOLUTION: A speaker array 10A is composed of a plurality of tweeter drivers 12T and a plurality of midrange drivers 12MR. All axes 18 of the tweeter drivers 12T and the midrange drivers 12MR are aligned radially with respect to a center point 20A. Front faces of the tweeter drivers 12T and the midrange drivers 12MR are equidistant from the center point 20A to define a single part-spherical array 10A. An open area 22A is defined on one side of the single part-spherical array 10A. Sound emitted from the tweeter drivers 12T and the midrange drivers 12MR will meet at the center point 20A, merge, and be emitted from the open area 22A while creating an acoustical impression that the sound all emanates from the center point 20A.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an array of speakers arranged to propagate sound in a manner that simulates sound emanating from a point source. [Background technology]

[0002] Related U.S. Patent No. 8,249,268 relates to a wooferless loudspeaker system having multiple tweeter drivers arranged in a spherical or partial spherical array, with each tweeter driver facing outward relative to the center of the sphere and with the axis of symmetry of each tweeter driver defining the radius of the sphere. Thus, acoustic energy radiates from the center of the sphere in all radial directions, or in a number of radial directions corresponding to the partial spherical array. The loudspeaker system disclosed in U.S. Patent No. 8,249,268 is highly effective in situations where it is desired to generate sound waves uniformly in all or multiple directions from an apparent single point source.

[0003] U.S. Patent No. 8,917,881 relates to an audio speaker system that includes multiple tweeter drivers arranged in a spherical array, each facing inward toward the center of the sphere, with the axis of symmetry of each tweeter driver defining the radius of the sphere. Thus, acoustic energy is directed radially inward toward the center of the sphere in all radial directions. Sound waves from the spherical array of tweeter drivers mix and recombine at the center of the sphere and are then reradiated outward in all directions, as if the center of the sphere were a point source for all output sound waves. While the speaker system disclosed in U.S. Patent No. 8,917,881 is highly effective in some environments, it has proven less effective in many others. For example, speakers are often mounted against or very close to one or more walls. In these situations, at least half of the reradiated sound waves emanating from the center of the sphere are directed toward the walls and reflected from the walls at multiple angles and locations. Therefore, the desired effect of sound waves appearing to emanate from a point source is lost in many situations where a spherical array of tweeter drivers is mounted close to a wall. As a result, there is a phase shift in the sound waves reaching the listener due to the different distances traveled by the sound waves from each tweeter driver, with or without wall reflections and from different points of wall reflection. In such situations, the various waves can create constructive and destructive interference with each other, significantly reducing the quality of the sound reaching the listener. Summary of the Invention [Problem to be solved by the invention]

[0004] In view of the above, it is an object of the present invention to provide a speaker system that is configured to allow a listener to perceive sound as being directed outward from an apparent point sound source. [Means for solving the problem]

[0005] The present invention relates to a speaker system including at least one partial-spherical speaker array. Each speaker includes a front surface from which sound is emitted and a rear surface opposite the front surface. An axis of symmetry extends concentrically through the front and rear surfaces of each speaker. The axes of symmetry of the speakers in the array extend radially through the center point of the sphere, with the front surface of each speaker facing toward the center point of the sphere. The speakers in at least one array form a portion of a sphere. For example, the partial-spherical array of speakers may form a hemisphere, or an array smaller or larger than a hemisphere. More specifically, the spherical array defines an aperture area. A plane passing through the center of the sphere and bisecting the aperture area can enclose a sector spanning an angle of 30° to 180° or more. Acoustic energy radiated from the speakers is directed toward the center of the sphere, where it mixes and recombines and radiates from the aperture area in a directional manner perceived as emanating from the center of the sphere.

[0006] Various speakers can be mounted within a structure intended to minimize vibrations in the structure and, therefore, sound generated by such vibrations. Additionally, the speaker mounting structure can have appropriate sealing and / or insulating materials to minimize sound generated by the speakers from traveling through the mounting structure and away from the opening in the partial spherical array.

[0007] In one embodiment, the speakers in the speaker array include or consist of a tweeter driver. In another embodiment, the speakers in the speaker array include a tweeter driver and a midrange driver. The tweeter driver and the midrange driver can be positioned at substantially the same radial distance from the center of the sphere. Furthermore, the tweeter driver and the midrange driver can be positioned in a particular circumferential pattern, such as alternating tweeter drivers and midrange drivers.

[0008] The at least one partial spherical speaker array may include at least first and second partial spherical speaker arrays. The first partial spherical speaker array may include a plurality of speakers positioned a first radial distance from the center of the sphere, while the second partial spherical speaker array may include a plurality of speakers positioned a second radial distance from the center of the sphere, the first and second radial distances being different from each other. The speakers of the first partial spherical array may be different from the speakers of the second partial spherical array. For example, tweeter drivers may be positioned in the first partial spherical array, and these tweeter drivers may be located a first radial distance from the center of the sphere. Midrange drivers may be positioned in the second partial spherical array, and these midrange drivers may be located a second radial distance from the center of the sphere. The second radial distance may be greater than the first radial distance. Furthermore, the drivers of the first and second partial spherical arrays are circumferentially offset from one another so that the drivers of the arrays closer to the center of the sphere do not obstruct the acoustic energy radiated from the drivers of the second partial spherical array. Thus, the acoustic energy emanating from both partial spherical arrays can reach the center point substantially unimpeded. This acoustic energy mixes and radiates from the aperture region of the arrays. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a side view of a partial spherical array of speaker drivers according to a first embodiment.

[0010] [Figure 2] FIG. 10 is a schematic cross-sectional view of a partial spherical array of loudspeakers according to a second embodiment.

[0011] [Figure 3] FIG. 10 is a schematic cross-sectional view of a partial spherical array of loudspeakers according to a third embodiment.

[0012] [Figure 4] FIG. 11 is a front view of a modified example of the third embodiment at an intermediate stage of manufacture.

[0013] [Figure 5] 5 is a front view of the embodiment shown in FIG. 4 at a subsequent stage in manufacture. DETAILED DESCRIPTION OF THE INVENTION

[0014] FIG. 1 illustrates a partial-spherical speaker array 10 comprised of multiple drivers 12. Each driver 12 has oppositely facing front and rear faces 14 and 16 disposed along an axis 18. The drivers 12 are oriented such that the axis 18 intersects a common center point, and the front faces 14 of all of the drivers 12 face toward the common center point. While the common center point is not visible in FIG. 1, it is visible in the second and third embodiments shown in FIGS. 2 and 3 and described below. Furthermore, in the embodiment of FIG. 1, the front faces 14 of the drivers 12 are at the same radial distance from the common center point. Thus, the front faces 14 of the drivers 12 are arranged in a spherically shaped array. However, the driver array 10 does not form a perfect sphere. Rather, the drivers 12 are arranged to leave an open area 22 for diffusing sound from the drivers 12 in the array 10. This arrangement directs the acoustic energy generated by the multiple drivers 12 toward the center point of the partial-spherical array 10. The acoustic energy mixes and combines at the central point and is re-radiated from the aperture area 22 as if the entire sound was emanating from the central point of the partial spherical array 10 .

[0015] FIG. 2 illustrates a second embodiment, which differs from the first embodiment in terms of the types of drivers comprising the array. More specifically, FIG. 2 illustrates a speaker array 10A consisting of multiple tweeter drivers 12T and multiple midrange drivers 12MR. The axes 18 of the tweeter drivers 12T and midrange drivers 12MR are all radially aligned with a center point 20A, and the front faces 14T and 14MR are equidistant from the center point 20A to form a single partial spherical array 10A. However, an open area 22A is formed on one side of the partial spherical array 10A, and the open area 22A spans an angle of approximately 45°. Smaller or larger angles are also possible for the open area 22A. In most embodiments, the open area spans an angle of 180° or less. However, open angles greater than 180° are also possible. As in the first embodiment, the sounds emitted from the tweeter driver 12T and the midrange driver 12MR meet and mix at the center point 20A and are radiated from the opening area 22A, creating the acoustic impression that the entire sound is emanating from the center point 22A.

[0016] FIG. 3 illustrates a third embodiment, which is a variation of the second embodiment. More specifically, FIG. 3 illustrates a partial spherical array 10B consisting of multiple tweeter drivers 12T and multiple midrange drivers 12MR, all of which have axes that form radii that intersect at a center point 20B. However, while the tweeter driver 12T has a front surface 14T that is a first radial distance from the center point 20B, the midrange driver 12MR has a front surface 14MR that is a second radial distance from the center point 20B, the second radial distance being greater than the first radial distance. As a result, the partial spherical array 10B of the second embodiment includes first and second partial spherical arrays 10T and 10MR. The tweeter driver 12T of the first partial spherical array 10T is circumferentially offset from the midrange driver 12MR of the second partial spherical array 10MR. Thus, the tweeter driver 12T does not impede the acoustic energy radiating from the midrange driver 12MR, and all of the acoustic energy is therefore directed towards the central point 20B. As in the first and second embodiments, the acoustic energy mixes and recombines at the central point 20B and exits through the open area 22B.

[0017] 4 and 5 illustrate various stages in the fabrication of a partial-spherical speaker array 10B according to one possible method of manufacture. More specifically, a frame 30 having substantially the form of a partial geodesic dome is formed from a suitable rigid material, such as wood or resin, as shown in FIG. 4. A tweeter driver 12T is securely attached to the inward-facing surface of the frame 30. A midrange driver is securely attached to the outer surface of the frame 30. The front faces of the tweeter driver 12T and the midrange driver 12MR both face inward toward the center point 20B. A sealing material and insulator 32 are then attached to the frame 30 to prevent acoustic energy from the tweeter driver 12T and the midrange driver 12MR from radiating through the area between them.

[0018] The present invention has been described with reference to certain specific embodiments. However, it will be apparent that various modifications can be made without departing from the scope of the present invention. For example, the number and type of drivers can vary. Furthermore, the size of the sound-emitting aperture area can vary. Furthermore, the frame can take many different forms.

Claims

1. a plurality of drivers each having a front face and a rear face and an axis of symmetry extending from said front and rear faces, each driver configured to propagate acoustic energy from said front face along said axis of symmetry; a frame supporting the plurality of drivers such that the plurality of drivers form at least one spherically generated driver array about a single center point, the axes of symmetry of the plurality of drivers converge at the single center point, and the front faces of the drivers face toward the single center point; the frame and the drivers are arranged to define an open area in the spherical driver array to accommodate propagation of acoustic energy from the frame and the spherically generated driver array; a sealing material attached to the frame that prevents acoustic energy from radiating through an area between the frame and the driver; 1. A speaker system, comprising: a first opening area extending from a first end of the first cavity to a second end of the first cavity; a second opening area extending from a second end of the first cavity to a second end of the first cavity; a second opening area extending from a second end of the first cavity to a second end of the first cavity;

2. 2. The speaker system of claim 1, wherein the front faces of the drivers are equidistant from the center point.

3. The speaker system of claim 2 , wherein the plurality of drivers includes a plurality of tweeter drivers and a plurality of midrange drivers.

4. 2. The speaker system of claim 1, wherein the plurality of drivers includes a plurality of tweeter drivers and a plurality of midrange drivers.

5. 5. The speaker system of claim 4, wherein the front faces of the tweeter drivers are at a first distance from the center point and the front faces of the midrange drivers are at a second distance from the center point, the second distance being different from the first distance, the tweeter drivers forming a first spherically shaped driver array concentric with the center point, and the midrange drivers forming a second spherically shaped driver array concentric with the center point.

6. The speaker system of claim 5 , wherein the second distance is greater than the first distance.

7. 7. The speaker system of claim 6, wherein the tweeter driver is circumferentially offset from the midrange driver so that the tweeter driver does not obstruct acoustic energy radiated from the midrange driver.

8. the plurality of drivers includes a plurality of tweeter drivers and a plurality of midrange drivers; 2. The speaker system of claim 1, wherein the frame has an inner surface facing the center point and an outer surface facing away from the center point, the tweeter driver is attached to the inner surface of the frame, and the midrange driver is attached to the outer surface of the frame.

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