Outdoor Speaker Enclosure

Abstract

An outdoor speaker enclosure comprising a box enclosing a loudspeaker, or a plurality thereof, opening outwardly of said box, and a cover for the speaker opening specially formed to resist the entry of moisture therethrough but being porous to permit the unobstructed egress of sound therethrough, said box having specially formed vents providing both for effective ventilation of the box interior and also for improving the sound reproduction quality of the speaker.

Description

This invention relates to new and useful improvements in speaker enclosures for radio, high-fidelity, and stereophonic sound reproduction systems, and has particular reference to speaker enclosures intended for usage outdoors, as on patios, porches, and the like, where they are necessarily exposed to the weather at least to some degree.

Exposure to the weather, particularly to rain, snow, dew, condensation, and other moisture, creates certain problems in connection with speaker enclosures. The enclosure must of course be supported by some means providing that the enclosure itself cannot directly engage any supporting surface on which moisture can collect, and from which it could seep into the enclosure. The speaker itself must be protected against rain or other moisture, even when said rain may be driven by a high wind. At the same time, the speaker opening of the enclosure should not be covered by any completely non-porous, waterproof layers, as these would muffle and otherwise reduce the quality of the sound reproduced by the speaker. Also, the enclosure itself should be well ventilated to provide for the disposition of any moisture which may find its way therein, or which may form therein by condensation due to substantial temperature changes in the surrounding air.

Accordingly, the object of the present invention is the provision of an outdoor speaker enclosure which fulfills all of the above enumerated requirements, in a novel, efficient manner. The present invention, to this end, involves two principal innovations. First, the speaker opening of the enclosure is provided with a special covering formed in a novel manner to resist the passage of rain or other moisture therethrough, while at the same time permitting passage of air therethrough with sufficient freedom not to muffle or otherwise detract from the quality of the sound reproduced by the speaker. Generally, this is accomplished by a cover including a plurality of spaced apart layers of cloth of successively greater resistance to the passage of water therethrough, and the provision of means for draining away any moisture from the spaces between said layers.

Second, there are provided special vents or openings for ventilating the enclosure. Speaker enclosures are already often provided with vents for the purpose of allowing the escape of sound generated in the enclosure from the inside of the speaker cone. Such vents thus cause the enclosure to act as a "sounding box" for the speaker, and have been found quite effective in strengthening and reinforcing the bass notes or other low-frequency sounds reproduced by the speaker. However, such vents have heretofore not been so arranged or disposed either to inhibit the entry of moisture into the enclosure, or to provide for circulatory ventilation of the interior thereof. The present invention provides for the formation and disposition of the vents whereby to perform these additional functions.

Other objects are simplicity and economy of construction, and efficiency and dependability of operation.

With these objects in view, as well as other objects which will appear in the course of the specification, reference will be had to the accompanying drawing, wherein:

FIG. 1 is a front elevational view of an outdoor speaker enclosure embodying the present invention,

FIG. 2 is a sectional view taken on line II--II of FIG. 1, with parts left in elevation,

FIG. 3 is a sectional view taken on line III--III of FIG. 2,

FIG. 4 is a sectional view taken on line IV--IV of FIG. 2, with parts left in elevation, and showing a slight modification of structure, and

FIG. 5 is an enlarged, fragmentary sectional view taken on line V--V of FIG. 1.

Like reference numerals apply to similar parts throughout the several views. The speaker enclosure forming the subject matter of the present invention includes a body member which may be formed of wood or any other suitable material, and may have the form of a generally rectilinear box, having a floor 2, left and right side walls 4 and 6, rear wall 8, front wall 10, and a top wall consisting of two inclined panels 12 and 14 whereby to form a peaked roof to better shed rain and the like, all of said members being rigidly connected together by any suitable means, not shown, whereby to form a unitary structure. The enclosure is supported above any supporting surface 16 by short legs 18 affixed thereto at each of its four corners. Roof panels 12 and 14 are extended outwardly to form eaves overhanging all of the front, rear, and side walls of the enclosure, and front wall 10 is recessed inwardly from the forward edges of side walls 4 and 6. A circular speaker opening 20 is formed in front wall 10, and a speaker 22 is affixed in said opening as by bolts 24, whereby to direct sound reproduced thereby forwardly from the enclosure. The speaker includes a speaker cone (not shown) coaxial therewith, which generally seals opening 20 of front wall 10, and which is vibrated by speaker coil 26 to generate sound. The rearward face of said cone is exposed to the interior of the enclosure through openings 28 formed in the speaker frame, so that vibration of the cone also vibrates the air within the enclosure. The necessary electrical connections to the speaker may be made by any suitable means, not shown.

The forward surface of front wall 10, of course including speaker opening 20 and the speaker 22 mounted therein, is covered by a protective panel indicated generally by the numeral 30. As best shown in FIGS. 1, 2, 4, and 5, said panel includes three planar, open frames 32, 34 and 36, formed of wood or other suitable material, assembled in overlying, coextensive relation to form a single composite frame. Overlying the outer or forward face of forwardmost frame 32 is a sheet 38 of stout, relatively coarse textile fabric. The material of sheet 38 should be of material sufficiently strong to resist damage by the physical scratching, gouging, and the like to which it may be subjected in outdoor usage, and is preferably formed of a synthetic material to resist damage by mildew and the like. Synthetics of the type and weight commonly used for outdoor carpeting has been found satisfactory. Water may pass through material of this sort with relative ease, and sheet 38 would hence not, of itself alone, adequately protect speaker 22 against moisture.

Panel 30 also includes two sheets 40 and 42 of a very closely woven moisture-repellent textile fabric overlying the entire area of the panel, the edges of sheets 40 and 42 being clamped respectively between frames 32 and 34, and between frames 34 and 36, whereby textile sheets 38, 40, and 42 are supported in closely spaced apart, parallel relation. A closely woven nylon fabric, such as is commonly used as a tenting material, has been found satisfactory for use in sheets 40 and 42. Coarse front sheet 38 is folded rearwardly around the edges of panel 30 and secured to the rearward surface thereof as by tacks 44 (see FIG. 5). Panel 30 is secured bodily against the forward surface of front enclosure wall 10 by screws 46. Referring to FIG. 5, it will be seen that the upper edge of the lower horizontal leg 32A of frame 32 is inclined forwardly and downwardly as indicated at 48, and that central frame member 34 has no horizontal lower leg at all, thereby providing an opening 50 between textile sheets 40 and 42 extending all the way to the extreme lower edge of panel 30. These latter provisions are for the purposes of drainage, as will appear. The upper edge of panel 30 is protected by the eaves formed by roof panels 12 and 14, and the vertical side edges of said panel are protected by their inclusion between the portions of side walls 4 and 6 projecting forwardly of front wall 10 (best shown in FIG. 2), so that water cannot work around the edges of the panel.

Also provided are a pair of vent tubes 52 and 54. As shown, said tubes are elongated and of rectangular cross-sectional contour, tube 52 being affixed vertically to the inner surface of side wall 4, opening at its upper end into the enclosure and having its lower end disposed in registry with a hole 56 formed in floor 2 with a screen 58 interposed therebetween to prevent the entry of insects into the enclosure. Tube 54 is affixed to the inner surface of roof panel 14, with its upper end opening into the enclosure and its lower end registered with a hole 60 formed in side wall 6 beneath the eave formed by said roof panel, with a screen 62 interposed therebetween.

In operation, it will be seen that rain or the like can pass with relative ease through the coarse textile sheet 38 forming the outer layer of protective panel 30 covering the speaker. However, sheet 38 does prevent the passage of much of the moisture, and furthermore absorbs much of the force of any wind which may be driving the rain, damping and reducing the air flow to the extent that any moisture entering between sheets 38 and 40 impinges against sheet 40 with much less force, and in much smaller quantities, than it originally engaged sheet 38. This together with the additional fact that sheet 40 (and 42) is formed of a very closely woven, moisture-shedding cloth such as nylon tenting material, results in fact that very little water ever passes through sheet 40, and virtually none through sheet 42. Any water collecting between sheets 38 and 40 drains outwardly through sheet 38 by reason of the bevel 48 of frame 32 at the lower edge of the space between these sheets, and any water collecting between sheets 40 and 42 drains downwardly through opening 50 formed by the elimination of the bottom leg of frame 34. The lower end of opening 50 is covered by sheet 38, but water can pass therethrough easily, thus the speaker is protected from rain or other moisture, while there are still air passages through the panel as are necessary for the efficient undistorted transmission of sound therethrough. Panel 30 is sufficiently effective that even when a stream from a garden hose is directed thereagainst with full force, substantially no water passes through inner sheet 42 thereof. This is a far more rigorous test than the panel would be required to withstand in any normal usage.

At the same time, the enclosure is continuously ventilated, to evaporate and carry away any moisture which may for example form therein by condensation, by air entering therein through tube 52, circulating through the interior thereof, and leaving through tube 54. As previously discussed, the venting of speaker enclosures for the acoustical purpose of strengthening and reinforcing low-frequency sounds is not new. Vent tubes 52 and 54 also perform this function. However, such prior acoustical venting has ordinarily been performed by a single vent not adapted to perform the circulatory ventilation required in an outdoor enclosure. The present structure supplies this lack of prior structures by dividing the vent into two sections disposed respectively adjacent the bottom and top of the enclosure, whereby to promote air circulation, by disposing the atmospheric ends of the openings in protected zones to at least inhibit the entry of wind-driven rain therein, and by the provision of tubes 54 extending upwardly inside of the enclosure from the atmospheric openings. These tubes virtually preclude the entry of any water into the enclosure through the vents, in any normal usage. The quality of the sound emanating from the vents is improved further by the provision of means preventing reflection, or reverberation, of sound between opposite interior walls of the housing. For this reason, floor 2, left side wall 6 and back wall 8 of the enclosure are provided with linings 64 consisting of slabs of sound-absorbing acoustical material.

FIG. 4 shows a structural modification supplying an alternative, or additional, means of venting the enclosure, consisting of short tubes 66 and 68 affixed in openings provided therefor in front wall 10 of the enclosure, respectively above and below speaker 22, but both behind protective panel 30 covering the front of the enclosure. These tubes provide for circulation of air through the enclosure, as do tubes 52 and 54, and are protected against the ingress of moisture therethrough by panel 30, in the same manner that said panel protects speaker 22. The use of tubes 66 and 68, rather than simply holes formed in front wall 10, is dictated by acoustical considerations with which this invention is not directly concerned, it having been found that tubular vents having certain proportions of length and cross-sectional contours produce better sound effects than others. These considerations apply also to the design of tubes 52 and 54. While tubes 66 and 68 have the advantage of being simpler and cheaper to install than tubes 52 and 54, they are less efficient for the purposes intended than tubes 52 and 54. Hence, while the two sets of tubes may be used either alternatively or concurrently, the use of tubes 52 and 54 is preferable if only one set is used. The lack of efficiency of tubes 66 and 68 arises from the fact that protective panel 30, while necessarily permeable to some degree to the flow of air therethrough, nevertheless still imposes considerable restriction to air flow therethrough. This restriction has little effect on high-frequency sounds, since the physical volume of air displaced by the speaker in high-frequency sound is very small, and very little air must be forced through the panel. However, with sounds of very low frequency, which emanate principally from the vents, large quantities of air are moved, resulting in quite noticeable inward and outward "puffing" of air through the vents. Hence, any substantial restriction of the flow of air through the vents results in muffling of the sound, so that the substantially unrestricted vents 52 and 54 are preferable. The flow restriction provided by panel 30 also inhibits the free circulatory ventilation of air desired in the present case for drying purposes. While the use of tubes 52 and 54, opening through the bottom and side of the enclosure, causes the low-frequency sounds to be initially directed in directions different from the axis of speaker 22, this is not disadvantageous. While high frequency sounds are directional in character, making it desirable to aim the speaker toward a desired listening area, low frequency sounds are more pervasive and non-directional in character, so that it makes little difference if the vents open downwardly, laterally, or even rearwardly of the speaker.

While I have shown and described certain specific embodiments of my invention, it will be readily apparent that many minor changes of structure and operation could be made without departing from the spirit of the invention.

Claims

What I claim as new and desire to protect by Letters Patent is:

1. An outdoor speaker enclosure comprising:

a. a hollow box-like body member having a speaker opening formed in a vertically extending wall thereof, said body member being adapted to have a speaker mounted therein so as to direct sound outwardly through said speaker opening, and

b. a protective panel secured to the outer surface of the body member wall in which said speaker opening is formed, and overlying said opening, said panel including a plurality of sheets of air-permeable fabric disposed in parallel, spaced-apart relation with spaces therebetween, said panel having a drain opening formed therethrough at the bottom of the space between a pair of adjacent fabric sheets, said drain opening providing for drainage, exteriorly of said body member, of any moisture collecting between said adjacent fabric sheets of said protective panel.

2. The structure as recited in claim 1, wherein said body member has a pair of vent holes formed therein and communicating respectively with upper and lower portions of the interior thereof.

3. The structure as recited in claim 2, wherein said vent holes open downwardly exteriorly of said body member with respect to adjacent portions of said body member, whereby to inhibit the entry of moisture into said body member through said holes.

4. The structure as recited in claim 2, with the addition of a pair of tubes disposed within said body member each with one end higher than the other, the lower end of each of said tubes communicating with one of said vent holes, with its upper end opening into the interior of said body member.

5. The structure as recited in claim 2, wherein said vent holes open through the vertically extending wall of said body member in which said speaker opening is formed, said protective panel which overlies said speaker opening also overlying said vent holes.

6. The structure as recited in claim 1 wherein the outer fabric sheet of said penal is of relatively tough, coarse fabric through which water may pass relatively easily, and wherein said panel includes a plurality of inner sheets of a relatively closely woven fabric through which water may pass only with relative difficulty, the drain opening of said panel being disposed between a pair of said inner sheets.

7. The structure as recited in claim 6 wherein said protective panel includes two of said relatively closely woven inner fabric sheets, and wherein said drain opening is disposed between said two inner sheets.

8. The structure as recited in claim 6 wherein said protective panel includes an open frame with said fabric sheets overlying the opening thereof, wherein said drain opening is formed through said frame intermediate said two inner sheets, and wherein the edge of said frame defining the bottom of the space between said outer fabric sheet and the adjacent inner sheet is inclined downwardly toward said outer sheet.