Audio speaker cover for enhanced audio performance

Abstract

An audio speaker cover with a central region and a peripheral region. The central region has a surface that faces an observer and a speaker cover body below the surface. The audio speaker cover body defines a plurality of apertures with lands between the apertures. The apertures have cylindrical walls that meet the surface orthogonally. Precisely engineered apertures permit minimal sound transmission loss and allow a high aperture density without sacrificing the ability of intervening lands in the audio speaker cover to protect an underlying speaker.

Claims

1. An audio speaker cover with a central region and a peripheral region, the central region having an area (C), an outer surface; and an audio speaker cover body below the outer surface, the audio speaker cover body defining a plurality of apertures with lands between at least some of the apertures, the apertures having cylindrical walls that meet the outer surface orthogonally, wherein the outer surface faces an observer and below the outer surface lies an inner surface that faces a speaker, at least some of the apertures in the central region having an area (A) at the outer surface that equals an area (A) at the inner surface, wherein the apertures occupy between 30 and 85 percent of the area (C) of the central region of the audio speaker cover at the inner surface and the outer surface.

2. The audio speaker cover of claim 1, wherein the lands occupy between 15 and 70 percent of the area (C) of the central region of the audio speaker cover.

3. The audio speaker cover of claim 1, wherein: the peripheral region of the audio speaker cover has an outer surface and an inner surface, the apertures of the central region have an average diameter (D) that is uniform across the cylindrical walls of the apertures; the apertures of the peripheral region have an average diameter (D+δ) at the outer surface and (D−δ) at the inner surface; and the apertures of the peripheral region having walls that remain smooth after deformation of a blank that is formed to create the central region and the peripheral region of the audio speaker cover, thereby presenting minimal disturbance to sound waves that pass therethrough.

4. The audio speaker cover of claim 1, wherein at least some of the plurality of apertures are non-circular.

5. The audio speaker cover of claim 4, wherein the non-circular apertures have a shape selected from the group consisting of oval, ovate, ovoid, elliptical, egg-shaped and combinations thereof.

6. The audio speaker cover of claim 1, wherein the sound transmission loss following passage of sound waves through the audio speaker cover over a frequency range of 60-15,000 Hz is less than about 5 dBm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 depicts an injection molded aperture section.

(2) FIG. 2 is a woven wire image.

(3) FIG. 3 is an expanded metal image.

(4) FIG. 4A is a punched aperture section.

(5) FIG. 4B is a top view of a punched aperture.

(6) FIG. 5A is an isometric view of a laser aperture and a section view thereof.

(7) FIG. 5B is a top view of an aperture made by a laser.

(8) FIG. 6 illustrates sections of a water jet cutting technique.

(9) FIG. 7 shows a chemical etching sheet metal section before and after etching.

(10) FIG. 8 is an image of a single sided etched aperture.

(11) FIG. 9A is a front view of an audio speaker cover with a patterned array of apertures of various sizes. Preferably, aperture density for a given aperture size per unit speaker cover surface area is greater than in prior practices.

(12) FIG. 9B is an enlarged top view of a linear array of columnar apertures.

(13) FIG. 10A is a sectional and top plan elevational view of a representative aperture defined in an audio speaker cover with orthogonality at the inner and outer surfaces thereof.

(14) FIG. 10B is a fragmented representative cross section through a peripheral region and a central planar region of an audio speaker cover.

(15) FIG. 10C is a fragmented sectional view of a curved peripheral region of an audio speaker cover.

(16) FIG. 11 illustrates an audio testing setup.

(17) FIG. 12 includes audio performance test results.

(18) FIG. 13 describes a representative Gardner Instrument Dart test setup.

(19) FIG. 14 portrays some representative Gardner Instrument Dart test results.

DETAILED DESCRIPTION

(20) As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.

(21) As those of ordinary skill in the art will understand, various features of the present invention as illustrated and described with reference to any one of the Figures may be combined with features illustrated in one or more other Figures to produce embodiments of the present disclosure that are not explicitly illustrated or described. The combinations of features illustrated provide representative embodiments for typical applications. However, various combinations and modifications of the features consistent with the teachings of the present disclosure may be desired for particular applications or implementations.

(22) Turning first to FIGS. 9A, 9B, 10A and 10B, there are depicted various aspects of representative embodiments of an audio speaker cover 10 with a central region 12 and a peripheral region 14. In some embodiments, the central region has a generally planar, concave or convex surface 16 and an audio speaker cover body 18 below the surface.

(23) In a preferred embodiment, the audio speaker cover body 18 defines a plurality of apertures 20. Lands 22 lie between at least some of the apertures 20. The apertures 20 have precisely formed cylindrical walls 24 that meet the generally speaker cover surface 16 orthogonally.

(24) With primary reference to FIG. 10B, the central region 12 of the audio speaker cover 10 can be imagined to occupy an area (C), the apertures 20 have a total area (A) and the lands have a total area (L). It can be seen that
C=A+L, and

(25) A=30 to 85 percent of C.

(26) Without being bound by a particular theory, it is believed that the relatively high percentage of aperture area (A) in relation to audio speaker cover (C) is enabled by precisely formed apertures 20. At least some of the apertures 20 have cylindrical walls 24 that have a uniform diameter along their depth. Further, at least some of the apertures 20 have shoulder portions 26 (FIG. 10A) that are substantially square, within generally acceptable manufacturing tolerances.

(27) In more detail (see, e.g., FIG. 10B), the audio speaker cover 10 has an outer surface 28 that faces an observer and an inner surface 30 that faces a speaker 32. At least some of the apertures 20 in the central region 16 have a total area (A) at the outer surface 28 that equals the total area (A) at the inner surface. 30.

(28) As noted earlier, in the audio speaker cover 10, at least some of the apertures 20 have a cylindrical wall 24 that has shoulder portions 26 that lie orthogonally at the outer surface 28 and inner surface 30.

(29) At least some cylindrical walls 24 are smooth, such that they offer minimal interference to sound waves that pass from the speaker 32 to the outer surface 28 of the audio speaker cover 10.

(30) Lands 22 (FIG. 10B) between the apertures 20 occupy between 15 and 70 percent of the area (C) of the central region 16 of the audio speaker cover. Without being bound by a particular theory, it is believed that the area of lands is relatively low in comparison to prior art solutions. This is likely due to precisely formed apertures with square shoulders between which there is minimal deformation or debris, unlike conventional aperture-forming techniques. As a result, the lands present minimal obstruction to sound waves that pass through the audio speaker cover (see, FIGS. 11-12). Some audio test results (FIGS. 11-12) confirm that sound distortion is minimal and there is little sound transmission loss.

(31) It will be appreciated that curvature of the audio speaker cover 10 during forming may have a distorting effect on otherwise perfectly cylindrical walls 24 and apertures 20 that are circular at the outer grill surface 28 and inner grill surface 30. See, e.g., FIG. 10C. Consider the peripheral region 14 of the audio speaker cover 10. That region has an outer surface 28 and an inner surface 30. However, the apertures 20 of the central region 12 have an average diameter (D) that is uniform across the cylindrical walls 24 of the apertures 20.

(32) It can be seen (FIG. 10C) that the apertures 20 of the peripheral region 14 have an average diameter (D+δ1) at the outer surface 28 and (D−δ2) at the inner surface 30. But at least some of the apertures 20 are cylindrical in the substantially undistorted central region 16, through which most of the sound waves are transmitted.

(33) The apertures 20 of the peripheral region 14 have walls 24 that remain smooth after deformation of a blank that forms the central region 16 and the peripheral region 14 of the speaker gill cover 10 so as to present minimal disturbance to sound waves that pass therethrough.

(34) FIG. 9A shows a central area of speaker cover in which the apertures 20 have a range of diameters at the outer surface 28. In such cases, the apertures proximate one region of the audio speaker cover have a diameter that differs from the diameter of apertures in another region of the audio speaker cover.

(35) In alternate embodiments, at least some of the apertures 20 are non-circular. In such cases, the non-circular apertures have a shape selected from the group consisting of oval, ovate, ovoid, elliptical, egg-shaped and combinations thereof.

(36) As mentioned above, it will be appreciated that in some embodiments, the central region 12 may be convex or concave, bulging outwardly or inwardly in relation to a speaker 32.

(37) Preferably, the audio speaker cover 10 has an inner surface 30 and outer surface 28 that is substantially free of deformation or blemish.

(38) Tests have shown that the sound transmission loss following passage of sound waves through the audio speaker cover over a frequency range of 60-15,000 Hz is less than about 5 dBm.

(39) To manufacture speaker covers with apertures having cylindrical walls and square shoulders, forming methods are followed that avoid problems created by such conventional approaches as injection molding, woven wire, expanded metal, punching, laser forming, and chemical etching.

(40) To make the disclosed speaker covers in volume, the skilled artisan may proceed by securing one or more blanks in relation to each other or to a holder, each blank having an inner surface and an outer surface. Apertures are then formed in the one or more blanks so that cylindrical walls define one or more apertures. The cylindrical walls meet at least some of the blank inner surfaces and outer surfaces orthogonally, often without the need for a de-burring step.

(41) In some embodiments, the audio speaker cover is made from a material selected from the group consisting of stainless steel, aluminum, low carbon steel, titanium, wood, plastics, composites including laminated layers and composites of one or more dissimilar materials.

(42) Experimental Data

(43) Experiments have been undertaken to confirm superior audio performance and reduced transmission loss following the suggested practices. Minimizing the sound transmission loss and distortion through a speaker cover is key to the performance of an audio system. Any material used to protect a fragile speaker cone from abuse will likely result in some degree of sound transmission loss at both low and high frequencies. It would be desirable to minimize that loss.

(44) FIG. 11 shows a test setup to compare the sound transmission response of two materials compared to air as a baseline. In this test setup, a speaker and a microphone are located 1 m from one another, representing an average distance from an automobile occupant. An initial baseline frequency sweep from 60-15,000 Hz) was measured with only air between the speaker and microphone located in an anechoic chamber. Higher end frequencies are more easily distorted than low end frequencies.

(45) Two cover materials (1—columnar apertures; 2—irregular apertures) were interposed between the speaker and microphone and run through the same frequency sweep as depicted in FIG. 12. The average aperture size of both materials was identical.

(46) Test results showed that the columnar apertures result in generally less sound transmission loss when compared to the irregular apertures at both low and high frequencies throughout the sweep. Lower levels of sound transmission loss mean superior audio performance.

(47) In summary, the innovation produced superior audio performance in relation to conventional approaches and maintained adequate strength to protect the fragile speaker cone. See, e.g., FIGS. 13-14.

(48) In some cases, it may be useful to deploy means for attaching the audio speaker cover to a mounting surface. If so, the means for attaching may include tabs and/or snap features extending from the peripheral region toward a speaker cone. Preferably, the means for attaching lie generally parallel to an imaginary line that is perpendicular to the central region.

(49) If desired, the audio speaker cover may have lands that are devoid of holes for accommodating additional layers of printed, machined, deposited, painted or drilled material or logos or coatings on an outer surface of the audio speaker cover for aesthetic purposes to achieve a desired appearance or texture or indicate a source or origin of the audio speaker cover. For example, badging may indicate the source or origin of the audio system.

(50) Further embodiments of the audio speaker cover may have means for attaching a low density masking material or foam to an underside of the audio speaker grill for hiding internal speaker components.

(51) While the best mode has been described in detail, those familiar with the art will recognize various alternative designs and embodiments within the scope of the following claims. While various embodiments may have been described as providing advantages or being preferred over other embodiments with respect to one or more desired characteristics, as one skilled in the art is aware, one or more characteristics may be compromised to achieve desired system attributes, which depend on the specific application and implementation. These attributes include, but are not limited to: cost, strength, durability, life cycle cost, marketability, appearance, packaging, size, serviceability, weight, manufacturability, ease of assembly, etc. The embodiments discussed herein that are described as less desirable than other embodiments or prior art implementations with respect to one or more characteristics are not outside the scope of the disclosure and may be desirable for particular applications.

(52) While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.

(53) TABLE-US-00001 TABLE OF REFERENCE NUMBERS Reference No. Component 10 Audio Speaker Cover 12 Central Region 14 Peripheral Region 16 Planar Surface 18 Audio Speaker Cover Body 20 Apertures 22 Lands 24 Cylindrical Walls 26 Shoulder Portions 28 Outer Surface 30 Inner Surface 32 Audio Speaker