WO2008033579A2

WO2008033579A2 - Speaker system for portable multimedia player

Info

Publication number: WO2008033579A2
Application number: PCT/US2007/061489
Authority: WO
Inventors: Joseph Onyuen Lee
Original assignee: Portable Sound Laboratories, Inc.
Priority date: 2006-09-12
Filing date: 2007-02-01
Publication date: 2008-03-20
Also published as: WO2008033579A3

Abstract

There is disclosed a speaker system. An enclosure may have a plurality of walls that define a resonant cavity. The resonant cavity may be essentially air-tight except for a speaker opening and a port opening. A speaker may be installed within the resonant cavity so as to cover and seal the speaker opening. A multiply folded tube formed a tuned port may be disposed within the resonant cavity. The tuned port may have a first end coupled to the port opening and a second end open to the resonant cavity.

Description

SPEAKER SYSTEM FOR PORTABLE MULTIMEDIA PLAYER

NOTICE OF COPYRIGHTS AND TRADE DRESS

[0001] A portion of the disclosure of this patent document contains material which is subject to copyright protection. This patent document may show and/or describe matter which is or may become trade dress of the owner. The copyright and trade dress owner has no objection to the facsimile reproduction by anyone of the patent disclosure as it appears in the Patent and Trademark Office patent files or records, but otherwise reserves all copyright and trade dress rights whatsoever. RELATED APPLICATION INFORMATION

[0002] This patent claims benefit of the filing date of provisional patent application Serial No. 60/825,398, entitled "Peripheral for Portable Music Player", filed 9/12/2006.

BACKGROUND

[0003] Field

[0004] This disclosure relates to compact high performance speaker systems suitable for use in peripherals for portable multimedia players.

[0005] Description of the Related Art

[0006] A speaker is an electro-mechanical transducer that converts an electric input into sound. A typical speaker may consist of a fixed magnet and a movable coil attached to a thin diaphragm. The diaphragm is commonly in the shape of a cone, but may be a dome or other shape. An audio signal applied to the coil causes oscillatory motion of the coil with respect to the magnet. The consequential movement of the diaphragm imparts motion, in the form of sound waves, to the air adjacent the diaphragm. Other types of speakers may use a piezoelectric or other transducer to impart motion to a diaphragm. A speaker may have a front side where the diaphragm is predominantly in contact with the adjacent air and a back side where the diaphragm is at least partially obstructed by the magnet or other transducer. Note that the front and back of the speaker are relative directions and do not connote a disposition of the speaker with respect to a listener or to the speaker cabinet as a whole.

[0007] A speaker may have a limited frequency range where the speaker's response (the ratio of sound volume produced to electric input power) is reasonably constant. This may be termed the speaker's "flat" frequency range. The response of the speaker is reduced for frequencies above and below the flat frequency range. [0008] A speaker system is a speaker mounted within an enclosure. The structure of the enclosure may alter the response of the speaker. Common types of speaker enclosures include a sealed enclosure where the back side of the speaker is enclosed in an air-tight sealed cavity. In this type of enclosure, the air in the sealed cavity is compressed and expanded by the motion of the speaker diaphragm. The air within the cavity acts like a spring that tends to resist the motion of the diaphragm.

[0009] A second known type of speaker enclosure is a bass reflex speaker enclosure in which the back of the speaker is enclosed in a volume that is substantially air-tight except for an opening, commonly termed a "port". The port causes the air inside the enclosed volume to resonate in the same manner that the air in a bottle resonates when an air current is directed across the mouth of the bottle. This effect is commonly called cavity resonance or Helmholtz resonance. In this description, the enclosed volume will be termed a "resonant cavity". The frequency at which the air within the resonant cavity resonates will be termed the "resonant frequency" of the resonant cavity. Note, however, that it is the air within the resonant cavity that resonates, rather than the walls or structure that define or bound the resonant cavity.

[0010] The dimensions of the port may be designed, or tuned, to determine the resonant frequency of the resonant cavity. To increase the low frequency efficiency of the speaker system, the port may be tuned such that the air in the resonant cavity resonates at or below the lower limit of the speaker's flat frequency range. DESCRIPTION OF THE DRAWINGS

[0011] FIG. 1 is a cross-sectional drawing of a prior art bass reflex speaker system.

[0012] FIG. 2 is a cross-sectional drawing of a bass reflex speaker system with a folded port.

[0013] FIG. 3 is a plan view of the interior of a speaker system enclosure.

[0014] FIG. 4 is a perspective view of the interior of a speaker system enclosure.

[0015] FIG. 5 is a perspective view of the interior of a speaker system enclosure.

[0016] FIG. 6 is a perspective view of the interior of a stereo speaker system enclosure.

DETAILED DESCRIPTION

[0017] Throughout this description, the embodiments and examples shown should be considered as exemplars, rather than limitations on the apparatus and methods disclosed or claimed.

[0018] Description of Apparatus

[0019] Referring now to FIG. 1, a bass reflex speaker system 100 is a type of speaker system in which the back of speaker 110 is enclosed in a resonant cavity 105. The resonant cavity 105 may be defined by a plurality of flat or curved walls that enclose the resonant cavity volume. The resonant cavity may be substantially air-tight except for a speaker opening 115 and a port opening 135. To be substantially air-tight, the amount of air that leaks in or out of the resonant cavity by paths other than the defined openings must have a negligible effect on the speaker system performance. The resonant cavity need not be hermetically sealed.

[0020] A speaker 110 may be disposed within the resonant cavity 105 such that sound waves emanating from the speaker 110 may propagate through the speaker opening 115. The speaker may sealably cover the speaker opening 115. Within this description, the term "sealably cover" means that the speaker is attached to the enclosure 100 in a manner that forms a substantially air-tight seal around opening 115, such that the speaker 110 effectively becomes part of a wall defining the resonant cavity 105. To facilitate forming a substantially air-tight seal around the speaker opening 115, intermediate material such as a gasket, seal material, or additional structure not shown in FIG. 1 may be disposed between the speaker 110 and the enclosure 100.

[0021] A port 120, also commonly called a vent, may consist of a pipe or duct with a first end 130 coupled to the air outside the resonant cavity 105 through the port opening 135, and a second end 140 open to the interior of the resonant cavity 105. One or both ends of port 120 may be flared or have a rounded edge 150. The port 120 may have a circular, rectangular, or other cross-section. The port 120 has a cross-sectional area (A) and a length (L).

[0022] As shown in FIG. 1, the resonant frequency of resonant cavity 105 is proportional to the square root of the cross-sectional area of the port 120 and inversely proportional to the square roots of the length of the port 120 and the volume of the resonant cavity 105. The effect of the port 120 is to utilize the sound emanating from the back of the speaker 110 to increase the efficiency of the speaker system for frequencies near the resonant frequency of the resonant cavity. The port 120 may be designed such that the cavity resonance improves the low frequency performance of the speaker system. The port 120 may be designed such that the air within resonant cavity 105 resonates at or below the lower limit of the flat frequency range of speaker 110.

[0023] The wall of the resonant cavity 105 which has the speaker opening 115 may be an exterior wall of the enclosure 100. The enclosure 100 may have other structure, not shown, outside of the resonant cavity 105, in which case the speaker 110 may be mounted to an interior structure of the enclosure 100. The enclosure 100 may be a generally rectangular box. The edges and comers of the enclosure may be sharp, beveled, or rounded. The enclosure 100 may be some shape other than rectangular, and the surfaces of the enclosure may be flat or curved.

[0024] A representative bass reflex speaker system may have external dimensions of 9 x 12 x 18 inches, a resonant cavity volume of about 1500 cubic inches, and a port having a diameter of 2 inches and a length of 5 inches. The resonant cavity of such a speaker system will have a resonant frequency about 45 Hertz.

[0025] Portable multimedia players may have a limited volume available for speaker systems enclosure and resonant cavities. The volume available may be particularly limited in compact portable multimedia players intended to be hand-held, or intended to be conveniently transported in coat pockets, purses, backpacks or other means. Compact multimedia players may only accommodate a resonant cavity having a volume of 5 cubic inches to 15 cubic inches.

[0026] A low resonant frequency may be achieved with a small resonant cavity volume if the area of the port is reduced or the length of the port is increased proportional to the reduction in resonant cavity volume. For example, a speaker system with a resonant cavity volume of 5.5 cubic inches, a port cross sectional area of 0.2 x 0.15 inches, and a port length of 4.5 inches will have a cavity resonant frequency about 75 Hertz. A cavity resonant frequency of 75 hertz may be appropriate for the small speaker that will fit within this limited volume. A larger resonant cavity will accommodate a larger speaker, which may necessitate a lower cavity resonance frequency. Thus speakers systems for hand-held portable multimedia players may generally require a port having a length of four inches or longer. A port length of four inches or longer may be long compared to the dimensions of the resonant cavity.

[0027] A long port may be accommodated within a speaker system enclosure as illustrated in FIG. 2. An enclosure 200 may include a plurality of walls that define a resonant cavity 205. A speaker 210 may sealably cover a speaker opening 215 in a wall of the resonant cavity 205. A port 220 may be a tube having a circular, rectangular, or other cross- section. The port 220 may have a first end 230 coupled to the air outside the resonant cavity 205 through a port opening 235. The port 220 may have a second end 240 open to the interior of the resonant cavity 205. The port 220 may be folded such that the length of the port 220 can be accommodated within the resonant cavity 205. While a single fold is illustrated, the port 220 may be coiled or multiply folded in a serpentine or other manner. Within this description, the terms "fold" and "folded" are intended to mean that the port 220 is curved, bent, turned, or otherwise not straight, but do not imply any particular method (such as mechanical forming or bending) was used to fabricate the port 120. The term "multiply folded" is intended to mean that the port 220 is curved, turned, or bent in at least two places along the length of the port 220.

[0028] FIG. 3, FIG. 4, and FIG. 5 show a plan view and perspective views of the interior of an exemplary speaker system. Throughout FIG. 3, FIG. 4, and FIG. 5, elements have been assigned three digit reference designators where the most significant digit is the drawing number and the two least significant digits define an element. Common elements having the same function in multiple figures will have reference designators with the same least significant digits. The description of common elements will not be repeated for each and every figure. An element that is not described in conjunction with a figure may be presumed to have the same function as that described for the counterpart element in a preceding figure.

[0029] Referring first to FIG. 3, the exemplary speaker system comprises an enclosure module 300 that defines a resonant cavity 305. The enclosure module 300 may have additional structure outside of resonant cavity 305 that is not shown. A speaker 310 and a port 320 are disposed within the resonant cavity 305. As will be explained subsequently, an enclosure cover is not shown in FIG. 3 so that the interior of the enclosure module 300 may be seen. Additionally a port cover is not shown in FIG. 3 so that the interior of the port 320 may be seen.

[0030] The speaker 310 may be disposed to sealably cover a speaker opening (not visible) in a wall of the resonant cavity 305 such that sound emanating from the speaker 310 may propagate outside of the resonant cavity 305.

[0031] The port 320 may have a first end 330 terminating at, and acoustically coupled to, a port opening 335 in a wall of the resonant cavity 305. The port 320 may have a second end 340 open to the interior of the resonant cavity 305. Between the first end 330 and the second end 340, the port 320, as shown, is folded through a sernicircular curve and three right-angle bends. Note that, as opposed to the previous examples of FTG. 1 and FIG. 2, the folded length of the port 320 may be parallel to the wall of the resonant cavity 305 on which the speaker 310 is mounted. The use of a semicircular curve and three right-angle bends in a generally spiral pattern is an example only. A port having the same overall length may be folded or continuously curved in many other patterns. The opening 335 may be in the wall of the resonant cavity on which the speaker is mounted, as shown in FIG. 3, or another wall.

[0032] FIG. 4 is a perspective view of the interior of the exemplary speaker system previously shown in plan view in FIG. 3. An enclosure module 400 may be comprised of a generally rectangular base 460 and enclosure wall sections 462, 464, 466, 468 extending from the base. The enclosure wall sections 462, 464, 466, 468 may be about normal to the plane of the base 460. The enclosure module 400 is a portion of a speaker enclosure that will be mated with an enclosure cover, not shown, to form a substantially sealed resonant cavity 405 enclosing the back of the speaker 410. The base 460 may have a shape other that rectangular, in which case there may be more or fewer enclosure walls. The base and enclosure wall sections may be flat or curved. While FIG. 4 shows a plurality of enclosure walls extending from the base, a portion or all of the enclosure walls may extend from the enclosure cover (not shown). The edges and corners of the enclosure module 400 may be sharp, beveled, or rounded. The speaker 410 may sealably cover a speaker opening (not visible) in the base 460, as shown in FIG. 4. The speaker 410 may be mounted to sealably cover a speaker opening in one of the enclosure wall sections 462, 464, 466, 468.

[0033] The enclosure module 400 may include at least one port wall that extends from the base into the interior of the resonant cavity 405. FIG. 4 identifies eight port wall sections 450a-h. However, the numbering of the port wall sections is somewhat arbitrary since the long multiply curved wall shown in FIG. 4 could be construed to be a single wall section. The port walls 450a-h extend from the base in generally the same direction as the enclosure wall sections 462, 464, 466, 468.

[0034] As shown in FIG. 4, the port walls 450a-h define the sides of a u-shaped channel having a first end coupled to an opening 435 in the base 460. The u-shaped channel has a second end 440 open to the resonant cavity 405. The u-shaped channel follows a semicircular curve and a series of three right-angle bends between the first end 430 and the second end 440. As will be explained subsequently, the u-shaped channel will be closed with a port cover to form a port with a rectangular cross-section.

[0035] The port 420 may be configured other than as a plurality of ports walls 450a-h extending from the base 460 with an affixable cover. AU or a portion of the port walls 450a- h may extend from the port cover. The port 420 may comprise a plastic or metal tube that is formed with the appropriate folds, disposed within the resonant cavity 405 and coupled to the opening 435.

[0036] The port 420 following a semicircular curve and three right-angle bends in a generally spiral pattern is an example only. A port having the same overall length may be folded or continuously curved in many other patterns. The port may be folded such that the opening 435 may be in the base 460 of the enclosure module 400 as shown in FIG. 4, or such that the opening 435 may be in an enclosure wall section 462, 464, 466, 468.

[0037] FIG. 5 is another perspective view of the interior of the exemplary speaker system previously shown in FIG. 3 and FIG. 4. A port cover 570 may be affixed to the port walls such that the base 560, the port walls, and the port cover 570 form a rectangular tube that constitutes a port. The port extends from a first end coupled to the air outside the enclosure via an opening in the enclosure (435 in FIG. 4) to a second end 540 open to the air within the resonant cavity 505. The port cover 570 may be permanently affixed to the port walls using ultrasonic welding, adhesive bonding, or any other appropriate method. The method of affixing the port cover to the port walls may form a substantially air-tight seal between the port cover and the port walls.

[0038] An enclosure cover, not shown in FIG. 5, may be permanently or removably affixed to the enclosure module 500. The enclosure cover may be adapted to form an airtight seal over resonant cavity 505, such that resonant cavity 505 is sealed except for the port. The enclosure cover may be permanently affixed to the enclosure module 500 using ultrasonic welding, adhesive bonding, or any other appropriate method. The enclosure cover may be removably affixed to the enclosure module 500 using mechanical fasteners such as screws, clips, or other suitable fasteners. The method of affixing the enclosure cover to the enclosure walls may form a substantially air-tight seal between the enclosure cover and the enclosure module 500. To this end, an interface between the enclosure module 500 and a removably affixed cover may be sealed by means of foam tape or other gasket material.

[0039] FIG. 6 is a perspective view of a dual or stereo speaker system. An enclosure module 600 may be comprised of a generally rectangular base 660 and a plurality of enclosure wall sections extending from the base. The enclosure module 600 is a portion of a speaker enclosure that will be mated with an enclosure cover, not shown, to form a first resonant cavity 610 and a second resonant cavity 615. The base 660 may have a shape other that rectangular, in which case there may be more or fewer enclosure walls. The base and enclosure wall sections may be flat or curved. While FIG. 6 shows a plurality of enclosure walls extending from the base, a portion or all of the enclosure walls may extend from the enclosure cover (not shown). The edges and corners of the enclosure module 600 may be sharp, beveled, or rounded.

[0040] A first speaker 620 may be installed within the first resonant cavity 610. The first speaker 620 may sealably cover a first speaker opening (not visible) in the enclosure module 600. A second speaker 625 may be installed within the second resonant cavity 615. The second speaker 625 may sealably cover a second speaker opening (not visible) in the enclosure module 600.

[0041] The enclosure module 600 may include at least one port wall extending from the base into the first resonant cavity 610. In the view of FIG. 6, the at least one port wall extending into the first resonant cavity is partially visible disposed beneath a first port cover 640. The enclosure module 600 may include at least one port wall extending from the base into the second resonant cavity. In the view of FIG. 6, the at least one port wall extending into the second resonant cavity is not visible, but is disposed beneath a second port cover 645. The enclosure module may be further comprised of additional walls that define spaces 660 and 670. The spaces 660 and 670 may be adapted to house components such as amplifiers, batteries, and other components. [0042] One or more enclosure covers, not shown, may be affixed to the enclosure module 600. The one or more enclosure covers may be permanently affixed to the enclosure module 600 using ultrasonic welding, adhesive bonding, or any other appropriate method. The one or more enclosure covers may be removably affixed to the enclosure module 600 using mechanical fasteners such as screws, clips, or other suitable fasteners. The enclosure cover may be adapted to form a substantially air-tight seal over the first resonant cavity 610 and the second resonant cavity 615, such that cavities 610, 615 are substantially air-tight except for the ports disposed beneath the first and second port covers 640, 645. To this end, an interface between the enclosure module 600 and a removably affixed cover may be sealed by means of foam tape or other gasket material.

[0043] Description of Methods

[0044] A method of fabricating a speaker system, such as the speaker systems previously shown in FIG. 4 - Fig. 6, will now be described. Referring back to FIG. 4, the enclosure module 400, including the base 460, enclosure walls 462, 464, 466, 468, and the at least one ports wall 450a-450k may be fabricated as a single piece. The enclosure module 400 may be fabricated, at least in part, by injection molding of a suitable polymeric material. The enclosure module 400 may be fabricated by other processes such as casting and machining. Machining processes may be required to finish an injection molded enclosure module. For example, one or more holes may be drilled to define mounting provisions for a speaker or a cover. [0045] Referring now to FIG. 5, the speaker 510 may be installed in the enclosure module 500 before or after the port cover 570 is affixed to the port walls. Installing the speaker 510 includes mounting the speaker 510 to sealably cover the speaker opening (not visible) in the enclosure module 500, and providing electrical connections (not shown) to the speaker 510. The port cover 570 may be affixed to the port walls using ultrasonic welding, adhesive bonding, or any other appropriate method. The method of affixing the port cover 570 to the port walls may form a substantially air-tight seal between the port cover and the port walls.

[0046] After the port cover 570 is affixed to the port walls and the speaker 510 is installed, a cover may be affixed to the enclosure walls 562, 564, 566, 568 such as to complete the speaker enclosure. The enclosure cover may be permanently affixed to the enclosure module 500 using ultrasonic welding, adhesive bonding, or any other appropriate method. The enclosure cover may be removably affixed to the enclosure module 500 using mechanical fasteners such as screws, clips, or other suitable fasteners. The method of affixing the enclosure cover to the enclosure walls may form a substantially air-tight seal between the enclosure cover and the enclosure module 500. To this end, an interface between the enclosure module 500 and a removably affixed cover may be sealed by means of foam tape or other gasket material.

[0047] Referring now to FIG. 6, a stereo speaker system may be fabricated and assembled using the previously described methods. The stereo enclosure module 600, including the base, enclosure walls, and first and second at least one port walls may be fabricated as a single piece by injection molding or other process. The speakers 620, 625 may be installed and the port covers 640, 645 may be affixed in any order. One or more enclosure covers (not shown) may be affixed as previously described to complete the enclosures 610, 615 after the speakers 620, 625 and port covers 640, 645 are in place.

[0048] Closing Comments

[0049] The foregoing is merely illustrative and not limiting, having been presented by way of example only. Although examples have been shown and described, it will be apparent to those having ordinary skill in the art that changes, modifications, and/or alterations may be made.

[0050] Although many of the examples presented herein involve specific combinations of method acts or system elements, it should be understood that those acts and those elements may be combined in other ways to accomplish the same objectives. Acts, elements and features discussed only in connection with one embodiment are not intended to be excluded from a similar role in other embodiments.

[0051] For any means-plus-function limitations recited in the claims, the means are not intended to be limited to the means disclosed herein for performing the recited function, but are intended to cover in scope any means, known now or later developed, for performing the recited function.

[0052] As used herein, "plurality" means two or more.

[0053] As used herein, a "set" of items may include one or more of such items. [0054] As used herein, whether in the written description or the claims, the terms "comprising", "including", "carrying", "having", "containing", "involving", and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases "consisting of and "consisting essentially of, respectively, are closed or semi-closed transitional phrases with respect to claims.

[0055] Use of ordinal terms such as "first", "second", "third", etc., in the claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed, but are used merely as labels to distinguish one claim element having a certain name from another element having a same name (but for use of the ordinal term) to distinguish the claim elements.

[0056] As used herein, "and/or" means that the listed items are alternatives, but the alternatives also include any combination of the listed items.

Claims

CLAIMSIt is claimed:

1. A speaker system, comprising: an enclosure including a plurality of walls defining a resonant cavity, wherein the resonant cavity is essentially air-tight except for a speaker opening and a port opening a speaker installed within the resonant cavity so as to sealably cover the speaker opening a tuned port comprising a folded tube disposed within the resonant cavity, the folded tube having a first end coupled to the port opening a second end open to the resonant cavity.

2. The speaker system of claim 1, wherein the tuned port further comprises: a plurality of port walls extending into the resonant cavity from a base, wherein the base is one of the plurality of walls defining the resonant cavity a port cover attached to the port walls wherein the port walls, the base, and the port cover form the folded tube.

3. The speaker system of claim 2, wherein the enclosure further comprises: an enclosure module comprising the base and at least one of the plurality of port walls fabricated as a single piece an enclosure cover joined to the enclosure module wherein the enclosure module and the enclosure cover, once joined, define the resonant cavity.

4. The speaker system of claim 3, wherein the enclosure module is adapted to be fabricated, at least in part, by injection molding.

5. The speaker system of claim 2, wherein the enclosure cover and at least one of the plurality of port walls are fabricated as a single piece.

6. The speaker system of claim 2, wherein the first opening is in the base.

7. The speaker system of claim 2, wherein the first opening and second opening are in the base.

8. The speaker system of claim 1, wherein the tuned port comprises a multiply folded tube.

9. The speaker system of claim 1, wherein the resonant cavity has a volume of about 5 cubic inches to about 15 cubic inches.

10. The speaker system of claim 9, wherein the tuned port has a length equal to or greater than 4 inches.

11. A method of fabricating a speaker system, comprising fabricating an enclosure module comprising at least one enclosure wall including a base, the at least one enclosure wall having a first opening and a second opening at least one port wall extending into the enclosure module from the base installing a speaker within the enclosure, the speaker disposed to sealably cover the first opening affixing a port cover to the port walls, wherein the port cover, at least one port wall, and base form a folded rectangular tube having a first end and a second end, the first end coupled to the second opening affixing an enclosure cover to the enclosure module after installing the speaker and affixing the port cover, wherein the enclosure cover and enclosure module define a resonant cavity.

12. The method of fabricating a speaker system of claim 11, where the enclosure module is fabricated as a single piece.

13. The method of fabricating a speaker system of claim 12, wherein the enclosure module is fabricated by injection molding.

14. A speaker system, comprising: an enclosure module comprising a base one or more enclosure walls extending from the base at least one port wall extending from the base an enclosure cover affixed to the enclosure walls such that the base, enclosure walls, and enclosure cover define a resonant cavity a speaker installed within said resonant cavity so as to sealably cover a first opening in the enclosure module a port cover affixed to the at least one port wall, wherein the base, at least one port wall, and the port cover form a folded rectangular tube having a first end coupled to a second opening in enclosure module and a second end open to the resonant cavity.

15. The speaker system of claim 14, wherein the enclosure module is adapted to be fabricated as a single piece.

16. The speaker system of claim 15, wherein the enclosure module is adapted to be fabricated, at least in part, by injection molding.

17. A stereo speaker system, comprising: an enclosure module comprising a base one or more enclosure walls extending from the base in a first direction first at least one port wall extending from the base in the first direction second at least one port wall extending from the base in the first direction at least one enclosure cover affixed to the enclosure walls, wherein the enclosure module and the at least one enclosure cover define a first resonant cavity and a second resonant cavity a first speaker installed within said first resonant cavity so as to sealably cover a first speaker opening in enclosure module a second speaker installed within said second resonant cavity so as to sealably cover a second speaker opening in the enclosure module a first port cover affixed to the first at least one port wall, wherein the base, the first at least one port wall, and first port cover form a first folded rectangular tube having a first end coupled to a first port opening in the enclosure module and a second end open to the first resonant cavity a second port cover affixed to the second at least one port wall, wherein the base, the second at least one port wall, and second port cover form a second folded rectangular tube having a first end coupled to a second port opening in the enclosure module and a second end open to the second resonant cavity.

18. The speaker system of claim 17, wherein the enclosure module is adapted to be fabricated as a single piece.

19. The speaker system of claim 18, wherein the enclosure module is adapted to be fabricated, at least in part, by injection molding.