Abstract:
An acoustic dampening sleeve for electronic equipment and a method of making the same is disclosed. An enclosure for abating noise generated therein includes a housing having a structure defining an internal chamber that has ventilation openings for the ingress and egress of cooling air. The structure cooperates with equipment disposed therein to define intake and exhaust plenums. Air outside the structure passes through the housing ingress opening, into the intake plenum, through the equipment, into the exhaust plenum, and exits the structure through the housing egress opening. The ingress and/or egress openings include baffles. The baffles comprise a resilient material defining openings in fluid communication with the internal chamber and a space outside the housing. The baffles are disposed to prevent or reduce a line of sight between the inside of the structure and the outside of the structure while maintaining open vent channels between the baffles.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 61/318,440, entitled Acoustic Dampening Sleeve for Electronic Equipment and Method of Making the Same, filed Mar. 29, 2010, incorporated by reference herein. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     The present invention relates to enclosures for electronics equipment. More particularly, the present invention relates to enclosures for electronic equipment that have the capability to ventilate the electronic equipment contained in the enclosure and reduce noise emanating from the enclosure. 
     2. Description of Related Art 
     The amount of electronic equipment found in the office and home has increased dramatically in recent years. For example, in an office environment, the use of server computers is commonplace. Likewise, high-speed Internet access is becoming increasingly available, adding to the amount of electronic equipment in use in the office environment, e.g. T1 or T3 connectivity equipment, ADSL or cable modems, Ethernet routers, and Wi-Fi access points. 
     As the speed and power of today&#39;s computer and electronic equipment has increased, so has the amount of “noise” and heat produced by such equipment. This is in part due to the physical size of the various devices becoming smaller and smaller which further complicates cooling the computer and electronic equipment. This is realized by there being less surface area available for heat exchange. This means that there must be increased airflow through the equipment casing to effect cooling. The amount of noise also is increased because the cooling equipment is more powerful, to provide greater capacity, and such cooling equipment also generates more noise. 
     There have been attempts to decrease noise by placing equipment in sealed enclosures. However, this attempt to trap noise also trapped heat in the sealed enclosure that was generated by the equipment. The inability to remove the trapped heat has induced equipment failure. To combat this, modern enclosures have been vented in an attempt to provide adequate airflow to the equipment. Venting the enclosure allows much of the noise created by computers and electronic equipment to escape the enclosure. 
     A perceived solution to the noise problem was to provide a dedicated electronic equipment room, e.g., a dedicated server room. These rooms are very often sealed and provided with a separate air conditioning system to remove the heat created by the equipment and maintain a temperature for safe operation of the equipment. Depending on the amount of equipment and size of the room, they can also include noise abatement measures. However, there are a number of drawbacks to this solution. Providing a dedicated electronic equipment room is expensive and often requires valuable office space to be sacrificed. In addition, although noise levels can be reduced outside the dedicated equipment room, the noise level in the dedicated equipment room can be quite high. This can create an unpleasant, and sometimes harmful, environment for those who must work on or with the electronic equipment. 
     Moreover, a dedicated server room may be prohibitively expensive for relatively smaller sites that do not have a large amount of computing equipment. For example, the use of “all-in-one” server systems, such as a blade system, enable organizations with minimal server needs to install the server capacity that is required at a particular moment in time and scale-up or scale-down as needed. A blade system typically includes a blade enclosure and one or more blade servers installed therein. 
     In contrast to a conventional server, a blade server may lack typical server components, e.g., a hard drive, a power supply, network connections, and/or human interface hardware. Instead, these components reside in the server enclosure and can be shared by any of the blade servers installed in the enclosure. In this way, the bulk and power consumption of the entire system is decreased. This permits a multi-server installation to exist in a relative small footprint (e.g., ˜300 mm high×˜500 mm wide×˜1000 mm long), which, in turn, allows the blade system to reside within an open office environment. 
     However, as mentioned above, concentrating multiple server computers into this relatively small footprint requires adequate cooling of the equipment in the blade system. Fan units mounted within the blade enclosure that draw air through the blade server component typically provide such cooling. Thus, the blade systems can emit a considerable amount of noise, which can lead to many of the problems set forth above. 
     Similar problems with noise were encountered in the home environment. As the amount of audio and video equipment in the home increases, so does the level of noise produced by the need to cool such equipment. For example, a common home theater system often includes one or more of the following items: a cable signal converter box, a satellite video tuner, a video cassette recorder (VCR), digital video recorder (DVR), a digital video disc (DVD) player, an audio tuner/amplifier system, and/or a media PC. Many people find this vast collection of electronic equipment unsightly. 
     To alleviate the problem, many home theater owners sought to hide the electronic equipment inside of enclosures or furniture. These owners encounter similar problems with heat and noise as do offices. Some home theater equipment is cooled by natural convection rather than forcing air through the equipment casing with cooling fans. When equipment is placed in an enclosure, heat is trapped, which can lead to equipment failure or a reduction of equipment life. 
     There is a need for a system and method that provides better noise and heat reduction for electronic equipment. The present invention overcomes the problems of the past by providing a novel system and method as set forth in the remainder of this specification referring to the attached drawings. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention is directed to an acoustic dampening sleeve for electronic equipment and a method of making the same. An embodiment of the present invention includes a housing for abating noise generated from within the housing. The housing includes a housing structure defining an internal chamber that has ventilation openings for the ingress and egress of cooling air. The housing structure cooperates with electronic equipment disposed therein to define an intake plenum and an exhaust plenum within the internal chamber. Air outside the housing structure passes through the ingress opening in the housing structure, into the intake plenum, through the electronic equipment, into the exhaust plenum, and exits the housing structure through the egress opening in the housing structure. At least one of the ingress opening and egress opening includes a baffle structure comprising a plurality of baffles. The baffles comprise a resilient material defining a plurality of openings in fluid communication with the internal chamber and a space outside the housing structure. The baffles are disposed to prevent a line of sight between the inside of the housing structure and the outside of the housing structure while maintaining open vent channels between the baffles. 
     In another aspect of the invention, each of the baffles comprises an elongate member of resilient noise-abating material having a substantially flat profile in a relaxed state that is maintained in a deformed state having a curved profile. 
     In still a further aspect of the invention, the housing structure includes a divider disposed in the internal chamber that cooperates with the electronic equipment therein to define the intake plenum and exhaust plenum. 
     In yet another aspect of the invention, the housing structure comprises a top wall, a first side wall, a second side wall, and a bottom wall. At least one of said walls has a noise-abating material disposed thereon. 
     In an aspect of the invention, the dampening sleeve also includes a cable egress port that includes a port structure and a removable cover. The port structure is adapted to be received at a port opening in the enclosure housing. The port structure includes an open back and top, and a removable cover. The removable cover is capable of being fixed to the port structure to accommodate a plurality of different sized cables. Noise-abating material is disposed inside the port structure and on the internal surface of the removable cover such that when the cover is fixed to the port structure the noise-abating material disposed on the internal surface of the removable cover mates with the noise-abating material inside the port structure to substantially seal at least one cable passing through the port structure into the housing structure such that noise emanating from the housing structure is abated from exiting through the port structure. 
     In another aspect of the invention, the dampening sleeve includes an intake chamber defined by a plurality of walls, at least one of said walls having noise-abating material disposed thereon. The intake chamber has an air intake and an air outlet, the air intake is in fluid communication with a space outside the housing structure and the air outlet is in fluid communication with the ingress opening. 
     In still another aspect of the invention, the dampening sleeve includes an exhaust chamber defined by a plurality of walls, at least one of said walls having noise-abating material disposed thereon. The exhaust chamber has an air intake and an air outlet, the air intake is in fluid communication with the egress opening and the air outlet is in fluid communication with a space outside the housing structure. 
     The present invention will now be described in greater detail in the remainder of the specification referring to the attached drawings. 
     These and other aspects of the present invention will be described in detail in the remainder of the specification, claims, and attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE INVENTION 
         FIG. 1  shows an exploded perspective view of an enclosure having features in accordance with an embodiment of the present invention. 
         FIG. 2  shows a front view of an enclosure having features in accordance with an embodiment of the present invention. 
         FIG. 3  shows a perspective view of an exhaust baffle assembly in accordance with an embodiment of the present invention. 
         FIGS. 4A-C  show a series of perspective views of an intake baffle assembly with an optional filtering device in accordance with an embodiment of the present invention. 
         FIG. 5  shows a cut-away perspective view of the main body of an enclosure in accordance with an embodiment of the present invention. 
         FIG. 6A  shows a cross-sectional side view of an intake baffle assembly in accordance with an embodiment of the present invention. 
         FIG. 6B  shows a cross-sectional side view a baffle in accordance with an embodiment of the present invention. 
         FIG. 7  shows a cut-away side view of an enclosure in accordance with an embodiment of the present invention. 
         FIG. 8A  shows the cut-away side view of  FIG. 7  with electronic equipment installed in the enclosure in accordance with an embodiment of the present invention. 
         FIG. 8B  shows the cut-away side view of  FIG. 7  with electronic equipment installed in the enclosure in accordance with an embodiment of the present invention. 
         FIG. 9  shows an assembled cable port for attachment to the main body of an enclosure in accordance with an embodiment of the present invention. 
         FIG. 10  shows a cable port attached to the main body of an enclosure illustrating cable installation in accordance with an embodiment of the present invention. 
         FIG. 11  shows the cable port of  FIG. 10  with a lid portion installed in accordance with an embodiment of the present invention. 
         FIGS. 12A-B  show a rear perspective view of an exhaust baffle assembly installed on the main body with an optional exhaust chamber cover installed in accordance with an embodiment of the present invention. 
         FIG. 13  shows a cut-away side view of an enclosure in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention is directed to systems and methods for enclosing electronic equipment in a noise-reducing sleeve that permits air to flow into and out of the enclosure. One embodiment of the invention lacks an air moving device, but, rather, relies on fans present in electronic equipment placed into the enclosure for exchange of air. The enclosure of the present invention provides for ingressing air into an enclosure through an ingress baffle arrangement and egressing air from the enclosure through an egress baffle arrangement. The baffle arrangements are constructed of resilient materials that are deformed into a configuration that prevents a line of sight through the baffle structure. The resilient materials have noise-absorbing properties. It is within the scope of the present invention that embodiments can have an intake chamber into which cooling air enters before passing though the ingress baffle arrangement and into the enclosure. Likewise, in some implementations, an exhaust chamber is provided into which air exiting the egress baffle arrangement enters. The optional intake and exhaust chambers also aid in reducing the amount of noise that escapes the enclosure. It is also within the scope of the present invention that embodiments of the present invention can use a cable egress port that allows cables and wiring to pass through the egress port while blocking the transmission of noise through the egress port. 
       FIG. 1 , generally at  100 , shows an embodiment of the present invention. Enclosure  100  has a main body that is generally box-shaped, having four sides, including a left side  102 , a right side  104  (hidden from view), a top side  106 , and a bottom side  108  (hidden from view). Enclosure  100  can be sized to receive various types of electronic equipment. In one implementation, the internal dimensions of enclosure  100  are such that an HP BladeSystem c3000 Enclosure fits snuggly within enclosure  100 . Enclosure  100  can be constructed of various materials, for example, wood, metal, or medium density fiberboard covered with a wood, plastic, or metal laminate. In the embodiment, portions of the inside walls of enclosure  100  may be coated with materials that have noise-absorbing or noise-abating properties. One set of materials useful for this purpose includes the ACOUSTIML™ multi-layer soundproofing material (commercially available from Acousti Products, LTD of Chesham, U.K.). Specifically, the 6.9 mm, 12 mm and/or 13 mm 3-layer acoustic composite materials by that manufacturer are suitable for use in embodiments of the present invention. This 3-layer material is constructed of a rubber-like acoustic barrier sandwiched between two layers of acoustic foam. By suspending the dense acoustic barrier layer between two foam layers, the material exhibits high sound transmission loss values and enhanced low frequency absorption performance. 
     Other examples of materials useful for this purpose include anti-resonant polymeric damping materials (for absorbing vibration) and/or polyurethane foam (such as that sold commercially as PYROSORB Flame Resistant Acoustic Foam). The polyurethane foam can be either flat foam (e.g., foam of 10 mm or 25 mm uniform thickness) or “egg box” foam. Examples of anti-resonant polymeric damping materials include TS3 1.8 mm thick chlorinated polyethylene (CPE) flexible polymeric damping sheet used in the automotive industry. The damping sheet may have adhesive backing to increase the ease of application. Further examples include one or a combination of polymer foams, fiberglass, carpet, and other anti-resonance sheet materials. Coating portions of the inside walls of enclosure  100  with anti-resonant materials helps to reduce the amount of noise transmitted to the walls of enclosure  100 , thereby reducing the amount of noise passed to the outside of enclosure  100  by the walls. 
     Electronic equipment (not shown) can be disposed in enclosure  100  and can rest on bottom side  108 . Enclosure  100  has an intake baffle arrangement  110 , which attaches to the front of enclosure  100 , and an exhaust baffle arrangement  112 , which attaches to the rear of enclosure  100 . Intake baffle arrangement  110  and exhaust baffle arrangement  112  may be removably connected to enclosure  100  in such a manner that air will enter enclosure  100  by way of intake baffle arrangement  110  and exit via exhaust baffle arrangement  112  through the operation of cooling fans included in the electronic equipment disposed within enclosure  100 . Intake baffle arrangement and exhaust baffle arrangement may be connect to enclosure  100  by a pin and groove mechanism discussed in more detail below. 
     Enclosure  100  can be implemented with a cable port  114 , which permits cables to enter enclosure without a significant disruption of the noise-abating characteristics of the enclosure. Cable port  114  is described in greater detail below. Enclosure  100  also, optionally, includes an intake chamber cover  116  that cooperates with intake baffle arrangement  110  to form an intake chamber. Likewise, enclosure  100  can include an exhaust chamber cover  118  that cooperates with exhaust baffle arrangement  112  to form an exhaust chamber. Theses features are described in more details below. 
       FIG. 2  shows a front view of enclosure  100  with intake baffle arrangement  110  installed in an operating configuration. Intake baffle arrangement  110  has a plurality of spaced-apart baffles  210 . The spaces between baffles  210  form a plurality of vents  220 . Vents  220  permit air outside enclosure  100  to pass between baffles  210  and into enclosure  100 . Meanwhile, although air can pass between baffles  210 , through vents  220 , baffles  210  have a shape that prevents a line-of-sight through intake baffle arrangement  110 . Intake baffle arrangement  110  has a four-sided frame structure  230  that cooperates with the individual baffles  210  to define the particular baffle shape, as described in more detail below. Intake baffle arrangement  110  can be constructed out of the same materials as generally set forth above for enclosure  100 . 
       FIG. 3  shows a perspective view of exhaust baffle arrangement  112  removed from the main body of enclosure  100 . Exhaust baffle arrangement  112  has features that are similar to intake baffle arrangement  110 . Namely, exhaust baffle arrangement  112  also has a plurality of vents with corresponding vents in-between. Exhaust baffle arrangement  112  has two mounting arms  310  that fit to a rear portion of the main body of enclosure  100 . Each mounting arm has a top and bottom groove  320  each of which mates with a complimentary pin (not shown) inside the main body of enclosure  100 . Thus, the groove and pin mounting mechanism provides for removal and replacement of exhaust baffle arrangement  112  without the use of tools. Optionally, exhaust baffle arrangement  112  may be fixedly joined to enclosure  100 . Intake baffle arrangement  110  may also be fitted with a locking mechanism to prevent undesired removal or tampering with the electronic equipment inside enclosure  100 . Intake baffle arrangement  110  has similar features enabling it to be mounted to a front portion of the main body of enclosure  100 . 
       FIGS. 4A-C  show a series of perspective views of intake baffle arrangement  110  with an optional filtering device  410  installed. Filtering device  410  slides into grooves in mounting arms  420  and is held adjacent to baffles  210 . Thus, filtering device  410  is disposed between baffles  210  and the interior of enclosure  100 . Filtering device  410  is constructed of filtering material known to those having skill in the art and prevents dirt, dust, and other particular contaminates from entering enclosure  100  and, thereby, enhances the life of the equipment inside. Filtering device  410  is readily removable for cleaning or replacement. 
       FIG. 5  shows a cut-away perspective view of the main body of enclosure  100 , intake baffle arrangement  110 , and exhaust baffle arrangement  112 . The figure illustrates how the baffle arrangements enable air to flow into enclosure  100  (represented by arrow  510 ) and out of enclosure  100  (represented by arrow  520 ) while reducing the amount of noise that escapes enclosure  100  (represented by arrows  530 ). 
       FIG. 6A  shows a cross-sectional side view of intake baffle arrangement  110 . As mentioned above, intake baffle arrangement  110  has multiple baffles  210  spaced-apart to create multiple vents  220 . The cross-sectional area of vents  220  is selected to permit sufficient airflow through enclosure  100 , as required by the particular application. In the embodiment described, 30% of the total cross-sectional area bounded by the frame of intake baffle arrangement is open to airflow (shown as  605 ). Greater and lesser amounts of open area are within the scope of the invention. 
     Meanwhile, the shape and arrangement of baffles  210  prevent a line-of-sight from the outside of enclosure  100  (shown as  610 ) to the inside of enclosure  100  (shown as  620 ). Specifically, in the embodiment shown in the figure, a lowest-most portion  630  of one baffle overlaps vertically with the upper-most portion  640  of another baffle. Thus, every noise path (shown as  650   a - c ) from the inside of enclosure to the outside of the enclosure will include one or more reflections off of baffles  210 . Because baffles  210  are constructed of noise-abating material, some amount of sound energy is absorbed with each reflection. Therefore, the volume of any noise escaping enclosure  100  is reduced. Some noise paths are completely prevented from escaping enclosure  100  (shown as noise path  650   c ). 
     Baffles  210  are constructed from a multi-layered resilient material, which absorbs some of the sound energy of noise attempting to escape from enclosure  100 . In addition, because the material is resilient, vibrations that could otherwise be induced in, or transmitted by, rigid baffle materials is reduced. In one illustrative example, the baffle material is the 3-layer ACOUSTIML™ material described above. This multi-layer “sandwich” is substantially flat in a relaxed state. 
     In one implementation, the baffles are formed from four strips of the 3-layer acoustic composite material, as shown in  FIG. 6B , essentially creating a double-thick layer of 3-layer acoustic composite material.  FIG. 6B  also illustrates a cross-sectional view of the 3-layer acoustic composite material. A first layer of acoustic foam  690   a  is joined to a dense acoustic barrier material  690   b , which is then joined to a second layer of acoustic foam  690   c . A main strip of this composite material  670   a  is joined to three other strips—a leading edge strip  670   b , a middle strip  670   c , and a trailing edge strip  670   d . A gap  680   a  between leading edge strip  670   b  and middle strip  670   c  and a gap  680   b  between middle strip  670   c  and trailing edge strip  670   d  provide increased flexibility to the multi-layer composite baffle that allows the assembled rectangular strips to deform more easily, as described below. The size of gaps  680   a - b  and the number of gaps can vary depending upon the desired shape of the deformed baffle. Likewise, gaps  680   a - b  can be eliminated and remain within the scope of the invention. 
     The assembled rectangular strips of the resilient material are deformed into substantially “V-shaped” baffles by engaging each long edge of the rectangle with support members that are separated by a distance that is less than the short edge of the rectangle.  FIGS. 6A-B  illustrate one such implementation. Support members  660  engage the opposing long edges of rectangular strips of material that form one of baffles  210  (a single support member  660  is shown in  FIG. 5  for illustrative purposes only). Because the distance between support members  660  is less than the short edge of the rectangular strip of baffle material, the baffle material is deformed into the substantially V-shaped baffle mentioned above. Support members  660  can be constructed of metal, plastic, wood, or other suitable materials that can maintain the resilient material in the desired deformed shape. Support members  660  can be mounted inside circular cutouts  665  in the inside wall of intake baffle arrangement  110 , which provide support and control the distance between support members  660 . Support members  660  may also be joined to the frame of intake baffle arrangement by gluing, welding, mechanical fasteners, and other known methods. 
     The arms of the V-shaped baffles shown in  FIGS. 6A-B  are of roughly equal length and are at an approximately 88-degree angle to each other (i.e., each support member  660  is at 44-degrees relative to the horizontal). However, greater and lesser angles may be used and remain within the scope of the invention. In addition, other cross-sectional shapes are contemplated, such as U-shapes, non-uniform curved shapes, and linear shapes. For example, the resilient material may be allowed to remain in its relaxed state (i.e., substantially flat), and mounted in relation to other substantially flat baffles to prevent a line of sight between the inside and outside of the enclosure. 
       FIG. 7  shows a cut-away side view of enclosure  100 . As mentioned above, portions of the inside walls of enclosure  100  may be coated with noise-abating material(s). As shown in the figure, top side  106  has a noise-abating material  710  disposed thereon. Meanwhile, bottom side  108  also has a noise-abating material  720  disposed on the inner surface thereof. A floor member  730  is disposed on top of noise-abating material  720  to support the electronic equipment placed inside enclosure  100 . Floor  730  protects noise-abating material  720  from damage by installation and/or removal of equipment from enclosure  100 . Although not shown, noise-abating material can be disposed on left side  102  and right side  104 . The noise-abating materials disposed on the inner walls of enclosure  100  reduce the amount of noise that is absorbed and re-radiated by the walls of the enclosure. The noise-abating material employed herein can be any one or combination of the materials mentioned above. However, it is intended that other materials that suppress low frequency noise generated by the electronics inside enclosure  100  and prevent the noise from passing through the structure of the enclosure may be used for noise-abating material. 
     Noise-abating material may also be disposed on one or more inside walls of intake chamber cover  116  and exhaust chamber cover  118 . As mentioned above, intake chamber cover  116  cooperates with intake baffle arrangement  110  to form an intake chamber  740 . This chamber reduces the amount of noise perceived outside of enclosure  100  by directing escaping sound toward noise-abating material  750  and then downward through an intake chamber inlet  760  toward the ground. Meanwhile, exhaust chamber cover  118  cooperates with exhaust baffle arrangement  112  to form exhaust chamber  770 . Noise-abating material  780  and exhaust chamber outlet  790  also reduce the amount of noise perceived from enclosure  100 .  FIG. 7  shows noise-abating material covering the entire surface of the inside walls of enclosure  100 . However, it is also contemplated that the noise-abating materials cover only a portion of the walls and still obtain a desired noise abatement effect. 
       FIG. 8A  shows the cut-away side view of  FIG. 7  with electronic equipment  800  installed in enclosure  100 . As disclosed above, electronic equipment  800  fits snuggly into enclosure  100  so that the outer surface of electronic equipment  800  is in contact with the noise-abating material disposed on the inner surface of the walls of enclosure  100 . Such an arrangement creates an intake plenum  810  between intake baffle arrangement  110  and electronic equipment  800  and an exhaust plenum  820  between the equipment and exhaust baffle arrangement  112 . Because electronic equipment  800  fits snuggly inside enclosure  100 , intake plenum  810  and exhaust plenum  820  are substantially sealed from one another. Thus, air exiting electronic equipment  800  is forced outside enclosure  100  through the exhaust assembly (generally,  830 ), while fresh air (i.e., relatively cooler air) is drawn into enclosure through the intake assembly (generally,  840 ). In this way, relatively hotter air leaving electronic equipment is not recycled into the intake plenum, which aids in cooling the equipment. 
     By fitting snuggly inside enclosure  100 , electronic equipment  800  is essentially suspended in noise-abating material. As describe above, this material is constructed of multiple layers. At the core of the multiple layers is a dense acoustic barrier material. The acoustic barrier material is bounded on each side with an acoustic foam material. The amount of vibration energy generated by electronic equipment  800  that is transmitted to the walls of enclosure  100  is greatly reduced by the described arrangement. The multi-layered material holds the equipment firmly in place inside enclosure  100 , however, because no rigid connection exists between electronic equipment  800  and the walls of enclosure  100 , very little vibration energy reaches the walls, from which it would be radiated as noise. 
     Although the embodiment set forth above describes the electronic equipment as fitting snuggly within enclosure  100 , other implementations do not require such a snug fit.  FIG. 8B  illustrates an alternate implementation of the embodiment designed to house electronic equipment  850  that is smaller than the inner dimension of enclosure  100 . One or more internal walls  860  can be added to maintain intake plenum  810  and exhaust plenum  820  substantially sealed from one another. Theses internal walls can be constructed of rigid or flexible materials, so long as the only significant air path between the plenums is through the equipment. In addition, an optional air-moving device  870  (e.g., a bank of fans) can be added to assist in the removal of warm air from exhaust plenum  820 . However, depending on the particular electronic equipment disposed within enclosure  100 , the fans present in the equipment may be sufficient to exhaust air from enclosure  100 . 
       FIG. 9  shows an assembled cable port  900  for attachment to the main body of enclosure  100 . Cable port  900  has a cable port body  910  that attaches to the main body of enclosure  100  adjacent to exhaust baffle arrangement  112 . Cable port  900  also includes a cable port cover  920  that mates with cable port body  910  to form a noise-abating seal that permits cables to pass into enclosure  100  from the outside. In certain implementations, cable port  900  cooperates with exhaust baffle arrangement  112  to seal the exhaust assembly ( 830  of  FIG. 8A ) to the main body of enclosure  100 . 
       FIG. 10  shows cable port  900  attached to the main body of enclosure  100  with cable port cover  920  removed to illustrate cable installation. Cable port  900  can be joined to bottom side  108  (hidden from view) of enclosure  100  by various methods such that cable port  900  is removable or solidly attached. For example, cable port  900  can be joined to bottom side  108  of enclosure  100  by nuts and bolts, screws, or other fasteners, or, cable port  900  can be joined by welding, soldering, or gluing. 
     Cable port  900  has a generally box-shaped structure including left  1010 , right  1020 , front  1030 , and rear  1040  upright sides. Cable port  900  also as a bottom side  1050  and a cable port baffle  1060 . Front upright side  1030  and rear upright side  1040  each have an opening that permits cables to pass through ( 1070  and  1080 , respectively). Cable port baffle  1060  is disposed within cable port  900  and is sufficiently wide to prevent a line-of-sight between openings  1070  and  1080 . With cable port cover  920  removed, cables  1090  can be placed through opening  1070  in front upright side  1030 , around cable port baffle  1060 , and through rear upright side  1080  without the need to thread cables  1090  through any openings. This advantageously allows for placement of cables  1090  having large end connectors without the need to first remove the connectors and replace the connectors once cables  1090  are in position. Likewise, cables  1090  can be easy removed from cable port  900  without having to modify end connectors present on cables  1090 . 
     Any one or more of the five sides of cable port  900  can be constructed of materials similar to those used for the walls of enclosure  100  described above. Likewise, the inside surfaces of the sides of cable port  900  can be treated or covered with materials that have noise-absorbing properties similar to those mentioned above. In the example embodiment, the inside surface of the bottom side  1050  of cable port  900  is covered with 10 and/or 25 mm thick egg box style polyurethane foam. Although not shown, egg box style polyurethane foam is also placed on the underside of cable port cover  920  such that when cover  920  is secured in its place, the polyurethane foam layers on cover  920  and bottom side  1050  have complimentary shapes. When pressed together, the egg box foam layers form a noise-absorbing seal around cables  1090 . Optionally, small vertical slits can be made in the polyurethane foam on cable port cover  920  (not shown) to facilitate sealing around cables  1090 . 
       FIG. 11  shows cable port  900  of  FIG. 10  with cable port cover  920  installed on cable port body  910 . As shown in the figure, cables  1090  pass through cable port and into enclosure  100 , while the noise-abating material disposed on the inner surfaces of cable port body  910  and cable port cover  920  cooperate to reduce the amount of noise that escapes enclosure  100 . 
       FIGS. 12A-B  show a rear perspective view of exhaust baffle arrangement  112  installed on the main body of enclosure  100  with optional exhaust chamber cover  118  installed. Also illustrated is cable port  900 . As shown in the figure, exhaust baffle arrangement  112  and cable port  900  cooperate to substantially seal the rear portion of the main body of enclosure  100 . Moreover, exhaust baffle arrangement  112  and cable port  900  are disposed relative to each other such that exhaust baffle arrangement  112  can be removed and replaced on enclosure  100  without affecting the placement of cables passing through cable port  900 . 
       FIG. 13  shows a cut-away side view of an enclosure  1300  in accordance with an embodiment of the present invention. Enclosure  1300  has some similar features to those described above in connection with enclosure  100 . However, the design of the baffle arrangements, internal airflow characteristics, and cable port differ from enclosure  100 . Specifically, enclosure  1300  is constructed of the same materials as those described above, and enclosure  1300  has an intake chamber cover  1305 , a main body  1310 , and an exhaust chamber cover  1315 . As with the previous embodiment, electronic equipment  800  fits snuggly into the enclosure so that the outer surface of electronic equipment  800  is in contact with noise-abating material disposed on the inner surface of the walls of enclosure  1300 . Optional filtering device  410  can also be installed as described in greater detail above. 
     Intake chamber cover  1305  is lined with noise-abating material  1320  and contains two curved baffles  1325   a  and  1325   b , which are constructed of the ACOUSTIML™ material described above. Like the other baffle structures described above, curved baffles  1325   a - b  can be constructed of other types of noise-abating material. Curved baffle  1325   a  is attached to the noise-abating material lining the inside of intake chamber cover  1305  along the bottom portion of the baffle and at the top end of the baffle. This feature maintains a curved portion  1330   a  of baffle  1325   a  that is not rigidly anchored within the intake chamber. As described above, because the baffle material is resilient, vibrations that could otherwise be induced in, or transmitted by, rigid baffle materials are reduced. Moreover, the curved shape is believed to aid in smooth airflow into main body  1310  of the enclosure. 
     Curved baffle  1325   b  is anchored at its top end by a support member  1335 , which functions as support member  660  described above. The bottom portion of curved baffle  1325   b  is affixed to an anchor  1340 . Anchor  1340  can be a rigid panel that extends across a portion of the intake chamber, and can be made, for example, from medium-density fiberboard. The walls of intake chamber cover  1305 , the noise-abating material lining thereof, and curved baffles  1325   a - b  define three spaces within the intake chamber. Airspace  1345   a  is defined by the noise-abating material liner and curved baffle  1325   a ; this airspace provides an additional noise-abating measure by reducing the amount of sound energy that is transmitted to the walls of the intake chamber cover. Airspace  1345   b  is defined by curved baffles  1325   a  and  1325   b  and provides a smooth airflow path for air entering enclosure  1300  while also permitting any sound energy escaping main body  1310  to reflect off of curved baffles  1325   a - b , thereby reducing the volume of the noise caused thereby. Airspace  1345   c  is defined by curved baffle  1325   b  and filtering device  410  (or the walls of main body  1310  if filtering device  410  is not installed). Airspace  1345   c  also provides a smooth airflow path for incoming air and noise-abating properties. Additional curved baffles, and the airspaces defined thereby, are within the scope of the invention. 
     Exhaust chamber cover  1315  is lined with noise abating-material  1350  and also has a curved baffle  1355 . Curved baffle  1355  is attached to the noise-abating material lining the inside of exhaust chamber cover  1315  along the bottom portion of the baffle and at the top end of the baffle. This feature maintains a curved portion  1360  of baffle  1355  that is not rigidly anchored within the exhaust chamber. As described above, because the baffle material is resilient, vibrations that could otherwise be induced in, or transmitted by, rigid baffle materials are reduced. Moreover, the curved shape is believed to aid in smooth airflow out of main body  1310  of the enclosure, thereby reducing the likelihood of the creation of pockets of trapped air. This further reduces the likelihood of the formation of “hot spots” within the enclosure. 
     Exhaust chamber cover  1315  includes a baffle arrangement  1365 . The baffles of this arrangement can be constructed in the same manner described above for the baffles of baffle arrangement  110 . Specifically, the baffles are constructed of one or more strips of the multi-layer acoustic composite material. Also, the baffles can be held in place, and maintained in a desired shape, by support members  1370  similar to support members  660 . Thus, as those described above, baffle arrangement  1365  provides gaps between the baffles that permit air to flow through the baffles while enabling escaping noise to be abated. As with the other baffle arrangements described herein, the long edges of the baffles are held in place such that the portion in-between the long edges is maintained in a resilient state. 
     As is shown in  FIG. 13 , the baffles of baffle arrangement  1365  need not extend the entire height of the exhaust chamber. Rather, a relatively large gap  1375  can be maintained above the top-most baffle and below the top edge of curved baffle  1355 . This feature provides for uninterrupted airflow along the top of the inside of main body  1310 , into the exhaust chamber, and along curved baffle  1355 , thereby reducing the likelihood of the creation of pockets of trapped air and the hot spots associated therewith. While the figure shows the baffles disposed along slightly more than half of the height of the exhaust chamber, the baffles can extend along the entire height or any portion of the height of the chamber. Likewise, the number of baffles can differ from the number shown in the figure. 
     Baffle arrangement  1365 , curved baffle  1355 , and noise-abating material  1350  cooperate to define two airspaces  1380   a  and  1380   b . Airspace  1380   a  is defined by noise-abating material  1350  and curved baffle  1355 ; this airspace provides an additional noise-abating measure by reducing the amount of sound energy that is transmitted to the walls of the exhaust chamber cover. Airspace  1380   b  is defined by curved baffle  1355  and baffle arrangement  1365  and provides a smooth airflow path for air exiting enclosure  1300  while also permitting any sound energy escaping main body  1310  to reflect off of curved baffle  1355  and/or baffle arrangement  1365 , thereby reducing the volume of the noise perceived. 
     Enclosure  1300  includes a cable port  1385 , which has many of the features of cable port  900 , described above. Specifically, cable port  1385  is generally boxed-shaped, is lined with noise-abating material, includes a cable port cover, has openings to permit cables to pass therethrough, and has at least one baffle to prevent a line-of-sight through the cable port. Relative to cable port  900 , in view of the entire enclosure, cable port  1385  is shorter than cable port  900  (with length extending left-to-right in the figure). Moreover, cable port  1385  is disposed further away from the back of electronic equipment  800  than the earlier described embodiment. In addition, a portion of a curved baffle  1390  is affixed to the floor of the closure, while the other end of the baffle is attached to, or rests against, cable port  1385 . This curved baffle  1390  and the increased clearance relative to the back of electronic equipment  800  reduces the likelihood of trapping air in space  1395 , thereby reducing heat retained inside the enclosure. 
     Enclosure  1300  includes a backwash preventer  1400  mounted on a lower portion of exhaust chamber cover  1315  inboard from the exhaust chamber outlet. In one implementation, backwash preventer  1400  is a brush-strip that extends along the width of enclosure  1300  (the width extending out of the page). Backwash preventer  1400  reduces the amount of hot exhaust air that passes under enclosure  1300  and reenters through the intake chamber inlet. While greatly reducing or preventing the passage of air, the brush-strip remains flexible enough permit the enclosure to be moved without causing damage to backwash preventer  1400 . Also, the flexibility of the brush-strip assists in maintaining a seal against possible irregular surfaces upon which enclosure  1300  may rest. Backwash preventer  1400  may be removable or fixedly attached and can be located elsewhere on the bottom of enclosure  1300 . 
     The terms and expressions that are employed herein are terms of description and not of limitation. There is no intention in the use of such terms and expressions of excluding the equivalents of the feature shown or described, or portions thereof, it being recognized that various modifications are possible within the scope of the invention as claimed. Moreover, optional features and multiple embodiments are described herein. It is understood that the features of one particular embodiment can be employed in other embodiments and remain within the scope of the invention.