PORTING
BACKGROUND OF THE INVENTION
The invention relates to porting and heat removal in acoustic devices, and more particularly to heat removal from ported acoustic enclosures
It is an important object of the invention to provide an improved apparatus for porting It is another object to remove undesired heat from an acoustic device
BRIEF SUMMARY OF THE INVENTION
According to an aspect of the invention, an electroacoustical device, comprises a loudspeaker enclosure including a first acoustic port, an acoustic driver mounted in the loudspeaker enclosure; and a heat producing device The acoustic driver and the acoustic port are constructed and arranged to coact to provide a cooling, substantially unidirectional airflow across the heat producing device, thereby transferring heat from the heat producmg device
In another aspect of the invention, an electroacoustical device includes an acoustic enclosure, a first acoustic port m the acoustic enclosure, an acoustic driver mounted in the acoustic enclosure for causing a first airflow m the port The first airflow flows alternatingly inward and outward m the port The device further includes a heat producmg device The acoustic port is constructed and arranged so that the first airflow creates a substantially unidirectional second airflow The device also includes structure for causing the unidirectional airflow to flow across the heat producing device
In another aspect of the invention, a loudspeaker enclosure having an interior and an extenor includes a first port having a first end having a cross-sectional area and a second end having a cross-sectional area, wherein the first end cross-sectional area is greater than the second end cross-sectional area The first end abuts the interior, and the second end abuts the extenor The enclosure also includes a second port The first port is typically located below the second port
In another aspect of the invention, a loudspeaker includes an electroacoustical transducer and a loudspeaker enclosure The loudspeaker enclosure has a first port having an
interior end and an exterior end, each having cross-sectional area The extenor end cross-sectional area is larger than the interior end cross-sectional area The device also includes a second port having an interior end and an extenor end The first port is typically located above the second port
In another aspect of the invention, a loudspeaker enclosure includes a first port having an interior end and an extenor end, each having a cross-sectional area The first port intenor end cross-sectional area is smaller than the first port extenor end cross-sectional area The enclosure also includes a second port having an intenor end and an extenor end, each end having a cross-sectional area The second port intenor end cross-sectional area is larger than the second port extenor end cross-sectional area
In another aspect of the invention, an electroacoustical device, for operatmg in an ambient environment includes an acoustic enclosure, compnsing a port having an exit for radiatmg pressure waves, an electroacoustical transducer, positioned m the acoustic enclosure, for vibrating to produce the pressure waves, a second enclosure having a first opemng and a second opening, wherein the port exit is positioned near the first opening so that the pressure waves are radiated into the second enclosure through the first openmg, a mounting position for a heat producing device in the first openmg, positioned so that air flowing into the opemng from the ambient environment flows across the mounting position
In another aspect of the invention, an electroacoustical device includes a first enclosure having a port having a terminal point for an outward airflow to exit the enclosure to an ambient environment and for an inward airflow to enter the enclosure The device also includes an electroacoustical transducer, compnsing a vibratile surface for generating pressure waves resulting in the outward airflow and the inward airflow The device also includes a second enclosure having a first opening and a second opening The port terminal point is positioned near the first opening and onented so that the port terminal outward flow flows toward the second openmg The port and the electroacoustical transducer coact to cause a substantially unidirectional airflow into the first opemng
In another aspect of the invention, an electroacoustical device, for operating in an
ambient environment includes an acoustic enclosure The enclosure includes a port having
an exit for radiating pressure waves The electroacoustical device further includes an
electroacoustical transducer, positioned in the acoustic enclosure, to provide the pressure waves The device also includes an elongated second enclosure having a first extremity and a second extremity in a direction of elongation There is a first opening at the first extremity and a second opening at the second extremity The port exit is positioned m the first opemng so that the pressure waves are radiated into the second enclosure through the first opemng toward the second opemng The device also includes a mounting position for a heat producing device in the elongated second enclosure, positioned so that air flowing mto the opemng from the ambient environment flows across the mounting position
In still another aspect of the invention, an electroacoustical device includes a first enclosure having a port having a terminal point for an outward airflow to exit the enclosure and for an mward airflow to enter the enclosure The device also includes an electroacoustical transducer, having a vibratile surface, mounted in the first enclosure, for generating pressure waves resulting in the outward airflow and the inward airflow The device also includes a second enclosure having a first opemng and a second opemng The port terminal point is positioned with the port terminal point m the second enclosure, onented so that the port terminal outward flow flows toward the second opemng The port and the electroacoustical transducer coact to cause a substantially unidirectional airflow into the first opemng
According to an aspect of the invention, there is a loudspeaker enclosure having a loudspeaker driver and a port tube formed with a vent intermediate its ends constructed and arranged to introduce leakage resistance into the port tube that reduces the Q of at least one standing wave excited in the port tube when acoustic energy is transmitted therethrough Ventmg may occur into the acoustic enclosure, into the space outside the enclosure, to a different part of the port tube, into a small volume, into a closed end resonant tube, or other suitable volume
Other features, objects, and advantages will become apparent from the following detailed description, when read in connection with the accompanying drawing m which
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING FIG 1 is diagrammatic view of a prior art device,
FIG 2 is a diagrammatic view of a device according to the invention,
FIGS 3 A and 3B are views of the device of FIG 2, illustrating the workings of the
device,
FIGS 4A - 41 are diagrammatic views of embodiments of the invention,
FIG 5 is a partial blowup of a loudspeaker incorporating the invention,
FIGS 6A and 6B are a diagram of another embodiment of the invention and a cross
section viewed along line B - B, respectively,
FIG 7 is a diagrammatic view of an implementation of the embodiment of FIGS 6A
and 6B
FIG 8 is a diagrammatic representation of a loudspeaker enclosure with a vented port
tube according to the invention,
FIG 9 shows a form of the invention with the port tube vented outside the enclosure, FIG 10 shows a form of the invention with the port tube vented to another portion of
the port tube,
FIG 11 shows a form of the invention with the port tube vented into a small volume, FIGS 12 and 13 show forms of the invention with the port tube vented into a closed
end resonant tube,
FIG 14 shows standing wave patterns in the port tube, and
FIG 15 shows a form of the invention with the vent asymmetrically located and
loaded by closed end tubes of different lengths
DETAILED DESCRIPTION
With reference now to the drawing and more particularly to FIG 1, there is shown a cross section of a prior art loudspeaker A loudspeaker 110 includes an enclosure 112 and an acoustic dnver 114 In the enclosure 110 are two ports 116 and 118, positioned so that one port 118 is positioned above the other Ports 116 and 118 are flared The upper port 118 is flared inwardly, that is, the intenor end 118i has a larger cross-sectional area than the extenor end 118e The lower port is flared outwardly, that is, the extenor end 116e has a larger cross-sectional area than the intenor end 116i
Refernng now to FIG 2, there is shown a cross sectional view of a loudspeaker
accordmg to the mvention Loudspeaker 10 includes an enclosure 12 and an acoustic dnver
14 having a motor structure 15 In the enclosure are two ports, 16 and 18, positioned so that
one port 16 is positioned lower in the enclosure 12 than the other port 18 Lower port 16 is flared inwardly, that is, intenor end 16i has a larger cross-sectional area than the extenor end 16e. Upper port 18 is flared outwardly, that is, extenor end 18e has a larger cross-sectional area than the intenor end 181 For purposes of illustration and explanation, the flares of port 16 and 18 are exaggerated Actual dimensions of an exemplary port are presented below In the enclosure there are heat producing elements The heat producing elements may include the motor structure 15 of the acoustic dnver, or an optional heat producing device 20, such as a power supply or amplifier for loudspeaker 10 or for another loudspeaker, not shown, or both Optional heat producing device 20 may be positioned lower than upper port 18 for better results It may be advantageous to remove heat from motor structure 15, positioning it lower than upper port 18 for better results
In operation, a surface, such as cone 13, of acoustic dnver 14 is dnven by motor structure 15 so that the cone 13 vibrates in the direction indicated by arrow 17, radiating sound waves, m this case to the extenor 24 of the enclosure and the intenor 22 of the enclosure In dnving the acoustic dnver cone, the motor structure 15 generates heat that is introduced into enclosure intenor 22 Sound waves radiated to the intenor 22 of the enclosure result in sound waves radiated out through ports 16 and 18 In addition to the sound waves radiated out through the ports, there is a DC airflow as indicated by arrow 26 The DC airflow is descnbed in more detail below The DC airflow transfers heat away from motor structure 15 and optional heat producing element 20 through upper port 18 and out of the enclosure, thereby cooling the motor structure 15 and the optional heat producing element 20
Refernng to FIGS 3a and 3b, the loudspeaker of FIG 2 is shown to explain the DC airflow of FIG 2 As the loudspeaker 10 operates, the air pressure P, inside the enclosure alternately increases and decreases relative to the pressure P0 of the air outside the enclosure. When the pressure P, is greater than pressure P0, as m FIG 3a, the pressure differential urges the air to flow from the intenor 22 to the extenor 24 of the enclosure When the P, pressure is less than the pressure P0, as in FIG 3b, the pressure differential urges the air to flow from the extenor 24 to the intenor 22 For a given magnitude of pressure across the port, there is more flow if the higher pressure end is the smaller end than if the higher pressure end is the
larger end When the airflow is from the intenor to the extenor, as m FIG 3a, there is more
airflow through outwardly flanng port 18 than through inwardly flanng port 16, and there is a net DC airflow 31 toward outwardly flanng port 18, in the same direction as convective airflow 32 When the airflow is from the extenor to the intenor, as in FIG 3b, there is more airflow through inwardly flanng port 16 than through outwardly flanng port 18, and there is a net DC airflow 31 away from inwardly flanng port 16 toward outwardly flanng port 18 Whether P, pressure is less than or greater than the pressure P0, there is a net DC airflow in the same direction Therefore, as intenor pressure P, cycles above and below P0, during normal operation of loudspeaker 10, there is a DC airflow flowing in the same direction as the convective DC airflow 32, and the DC airflow can be used to transfer heat from the intenor of the enclosure 24 to the surrounding environment
A loudspeaker according to the invention is advantageous because there is a port-induced airflow that is in the same direction as the convective airflow, increasing the cooling efficiency
Empincal results indicate that thermal nse of a test setup using the configuration of FIG 1 was reduced by about 21% as compared to the thermal nse with no signal to the acoustic dnver 114 With the configuration of FIG 2, the thermal nse was reduced by about 75% as compared to the thermal nse with no signal to acoustic dnver 14
Refernng to FIGS 4A - 41, several embodiments of the invention are shown In FIG 4A, lower port 16 is a straight walled port, and the upper port is flared outwardly In FIG 4B, upper port 18 is a straight walled port, and the lower port is flared inwardly The embodiments of FIGS 4A and 4B have an airflow similar to the airflow of the embodiment of FIGS 2 and 3, but the airflow is not as pronounced In FIG 4C, it is shown that the ports 16 and 18 can be on different sides of the enclosure 12, if the enclosure has curved sides, the ports 16 and 18 can be at any point on the curve FIG 4D is a front view, showing that acoustic dnver 14 and the two ports 16 and 18 may be non-colhnear The position of the acoustic dnver 14 and alternate locations shown in dashed lines, and the position of ports 16 and 18 and alternate locations shown in dashed lines show that the acoustic dnver 14 need not be equidistant from ports 16 and 18 and that the acoustic dnver need not be vertically centered between ports 16 and 18 In the embodiment of FIG 4E, the outwardly flanng upper port 18 is in the upper surface, facing upward, and the inwardly flanng lower port 16 is
in the lower surface If the lower port 16 is in the lower surface as in FIG 4E, the enclosure would typically have legs or some other spacing structure to space lower port 16 from surface 28 on which loudspeaker 10 rests FIG 4F shows that the port walls need not diverge linearly, and that the walls, in cross section, need not be straight lines The embodiment of FIG 4G shows that the divergence need not be monotomc, but can be flared both inwardly and outwardly, so long as the cross sectional area at the exterior end 18e of the upper port 18 is larger than the cross sectional area at the interior end 18i, or so long as the cross sectional area at the exterior end 16e of the lower port 16 is smaller than the cross sectional area at the interior end 16i, or both Flaring a port in both directions may have acoustic advantages over straight walled ports or ports flared monotomcally In FIGS 4H and 41, the invention is incorporated in loudspeakers with more complex port and chamber structures, and with an acoustic driver that does not radiate directly to the extenor environment Third port 117 of FIG 5 is used for acoustic purposes The operation of the embodiments of FIGS 4H and 41 causes interior pressure P, to cycle above and below extenor pressure P0> resulting in a net DC airflow as in the other embodiments, even though acoustic driver 14 does not radiate sound waves directly to the extenor of the enclosure Aspects of the embodiments of FIGS 4A - 41 can be combined FIGS 4A - 41 illustrate some of the many ways in which the invention may be implemented, not to show all the possible embodiments of the invention In all the embodiments of FIGS 4A - 41, there are an upper port and a lower port, and either the upper port has a net outward flare, or the lower port has a net inward flare, or both
Refernng now to FIG 5, there is shown a partially transparent view of a loudspeaker incorporating the invention The cover 30 of the umt is removed to show internal detail of the loudspeaker The embodiment of FIG 5 is in the form of FIG. 41 The reference numerals identify the elements of FIG 5 that conespond to the like-numbered elements of FIG 41 Acoustic dnver 14 (not shown in this view) is mounted in cavity 32 Openmgs 19 help reduce standing waves in the port tube as descnbed below The vanations in the cross sectional areas of ports 16 and 18 are accomplished by varying the dimensions in the x, y, and z directions Appendix 1 shows exemplary dimensions of the two ports 16 and 18 of the loudspeaker of FIG 5
Referring to FIGS 6A and 6B, there are shown two diagrammatic views of another embodiment of the invention In FIG 6 A, ported loudspeaker 10 has a port 40 that has a port exit 35 inside airflow passage 38 In one configuration port 40 and airflow passage 38 are both pipe-like structures with one dimension long relative to the other dimensions, and with opemngs at the two lengthwise ends, port exit 35 has a cross-sectional area As smaller than the cross-sectional area A of the airflow passage 38, and port exit 35 is positioned m the airflow passage so that the longitudinal axes are parallel or coincident Some considerations for the shape, dimensions, and placement of port 40, port exit 35, and airflow passage 38 are presented below Positioned inside airflow passage 38 is heat producing device 20 or 20', shown at two locations In an actual implementation, the heat producing device or devices can be placed at many other locations in airflow passage 38
When acoustic dnver 14 operates, it induces an airflow in and out of the port 40 When the airflow induced by the operation of the acoustic dnver is in the direction 36 out of the port 40, as shown in FIG 6A, the port and airflow passage act as a jet pump, which causes airflow in the airflow passage 38 in the same direction as the airflow out of the port, in this example in airflow passage opening 42, through the airflow passage m direction 45 and out airflow passage opemng 44 Jet pumps are descnbed generally in documents such as at the internet location
http //www mas ncl ac uk/~sbrooks/book/msh mit edu/2006/Textbook/Nodes/chap05/nodel 6 html a printout of which is attached hereto as Appendix 2
Refernng to FIG 6B, when the acoustic dnver induced airflow is in the direction 37 into port 40, there is no jet pump effect The airflow into the port 40 comes from all directions, including inwardly through airflow passage opening 42 Since the airflow comes from all directions, there is little net airflow within the airflow passage
To summanze, when the acoustic dnver induced airflow is in direction 36, there is a
jet pump effect that causes an airflow in airflow passage opening 42 and out passage opemng
44 When the acoustic dnver induced airflow is in the direction 37, there is little net airflow
in airflow passage 38 The net result of the operation of the acoustic dnver is a net DC
airflow in direction 45 The net DC airflow can be used to transfer heat away from heat
producing elements, such as devices 20 and 20', that are placed in the airflow path
There are several considerations that are desirable to consider in determining the dimensions, shape, and positioning of port 40 and airflow passage 38. The combined acoustic effect of port 40 and passage 38 is preferably in accordance with desired acoustic properties It may be desirable to arrange port 40 to have the desired acoustic property and airflow passage 38 to have significantly less acoustic effect while maintaining the momentum of the airflow in desired direction 45 and to deter momentum in directions transverse to the desired direction To this end port 40 may be relatively elongated and with a straight axis of elongation parallel to the desired momentum direction It may be desirable to structure airflow passage 38 to increase the proportion of the airflow is laminar and decrease the proportion of the airflow that is turbulent while providing a desired amount of airflow
Referring to FIG 7, there is shown a mechanical schematic drawing of an actual test implementation of the embodiment of FIGS 6A and 6B, the elements numbered similarly to the corresponding elements of FIGS 6A and 6B In the test implementation device the airflow passage 38 and the heat producing device were both parts of a unitary structure A resistor was placed m thermal contact with at heat sink m a tubular form with appropriate dimensions so it could function as the airflow passage 38 With current flowing through the resistor and with acoustic dnver 14 not operating, the temperature in the vicinity of the heatsink rose 47° C With the acoustic dnver operating at 1/8 power, the temperature in the vicinity of the heatsink rose 39° C With the acoustic dnver operating at 1/3 power radiating pink noise, the temperature in the vicinity of the heatsink rose 25° C Additionally, the thermal effect of the device at other points in the loudspeaker enclosure was measured For example, at area 55, convection heating caused the temperature to nse 30.5° C with current flowing through the resistor and with acoustic dnver 14 not operating With the acoustic dnver operating at 1/3 power, the temperature in the vicinity of the heatsink rose 30 5° C With the acoustic dnver operating at 1/8 power radiating pink noise, the temperature in the vicinity of the heatsink rose 30 5° C With the acoustic dnver operating at 1/3 power radiating pink noise, the temperature in the vicinity of the heatsink rose 21° C This indicates that if the acoustic dnver operates at high enough power, thereby moving more air than when it operates at lower power, the airflow resulting from a loudspeaker according to the invention transfers heat from areas near, but not directly in, the airflow
Referring to FIG 8, there is shown a diagrammatic representation of a loudspeaker
enclosure 61 having a driver 62 and a port tube 63 formed with a vent 64 typically located at a point along the length of port tube 63 corresponding to the pressure maximum of the dominant standing wave established in port tube 63 when dnver 62 is excited to reduce audible port noise Acoustic damping material 90, for example, polyester or cloth, may be positioned in or near vent 64
This aspect of the invention reduces the objectionabihty of port noise caused by self resonances For example, consider the case of increased noise at the frequency for which one-half wavelength is equal to the port length In this example of self resonance, the standing waves in the port tube generate the highest pressure midway between the ends of port tube 63 By establishing a small resistive leak near this point with vent 64 in the side of the tube, the Q of the resonance is significantly diminished to significantly reduce the objectionabihty of port noise at this frequency The acoustic damping matenal 90 may further reduce the Q of high frequency resonances
The leak can occur through vent 64 into the acoustic enclosure as shown in FIG 8 Alternatively, the leak can leak into the space outside enclosure 61 through vent 64' of port tube 63' as shown in FIG 9 The port tube 63" could leak through vent 64" to a different part of port tube 63" as shown in FIG 10 Port tube 63'" could leak through vent 64'" into a small volume 65 as shown m FIG 11 The port tube 63"" could leak through vent 64"" into a closed end resonant tube 65' In the embodiments of FIGS 9-12, there may be positioned near the vent 64' - 64"" acoustic damping matenal 90
An advantage of the embodiments of FIGS 11 and 12 is that the disclosed structure may have insignificant impact on the low frequency output The acoustic damping material 90 may further reduce the Q of high frequency resonances
The structures shown in FIGS 9-12 reduce the Q of the self resonance corresponding
to the half-wave resonance of the port tube The principles of the invention may be applied
to reducing the Q at other frequencies corresponding to the wavelength resonance, 3/2
wavelength resonance and other resonances To reduce the Q at these different resonances, it
may be desirable to establish vents at points other than midway between the ends of the port
tubes For example, consider the wavelength resonance where pressure peaks at a quarter of
the tube length from each end A vent at these locations is more effective at diminishing the
Q of the wavelength resonance than a vent at the midpoint of the tube Vents at these pomts
and other pomts may furnish leakage flow to the same small volume for the midpoint vent
Alternatively, each may have dedicated closed end resonant tubes Still alternatively, they may allow leakage to the inside or outside of the enclosure To reduce the audible output at a vanety of resonances, a multiplicity of vents may be used, including a slot, which can be considered as a senes of contiguous vents
There are numerous combinations of venting structures, structures defining volumes for venting, including resonant closed end tubes
Refernng to FIG 13, there is shown a schematic representation of an embodiment of the mvention for reducing Q of the half-wave resonance of a port tube 73 of length Al m enclosure 71 having dnver 72 using tube 75 with a closed end of length 0 3 Al having its open end at vent 74 FIG 14 shows the standing wave for the half-wave resonance along the length of tube 73, (in the absence of resonant tube 75), showing the pressure distribution 76 and volume velocity distnbution 77 The pressure is at a maximum at point 74 Energy from the standing wave in the port tube 73 is removed from the port tube at maximum pressure point 74 The energy may be dissipated by dampmg matenal 90 in the resonant tube, significantly reducing the Q of the half-wave resonance
In the resonant tube 75 may be acoustic damping matenal The acoustic dampmg
matenal may fill only a small portion of the resonant tube 75 as indicated by acoustic
dampmg matenal 90, or may substantially fill resonant tube as indicated in dotted line by
acoustic dampmg matenal 90' The acoustic damping matenal 90 or 90' reduces the Q of
high frequency multiples of the half-wave resonant frequency
Refernng to FIG 15, there is shown a diagrammatic representation of a port tube 83 with a vent 84 six-tenths of the port tube length s from the left end and four-tenths of the port tube length from the nght end terminated in a closed end resonant tube 85 of length 0 5 the length of port tube 83 and diameter dl of 3" and another closed end tube 85' of length 025 that of port tube 83 and diameter d2 of 1 5" In one or both of closed end resonant tube 85 and closed end resonant tube 85' may be acoustic damping matenal 90 As with the embodiment of FIG 13, the acoustic dampmg matenal may fill a portion of one or both of closed end resonant tubes 85, 85', or may substantially fill one or both of close end resonant tubes 85,85'
It is evident that those skilled in the art may now make numerous uses and
modifications of and departures from the specific apparatus and techniques disclosed herein
without departing from the inventive concepts Consequently, the invention is to be construed as embracing each and every novel feature and novel combination of features present in or possessed by the apparatus and techniques disclosed herein and limited only by the spirit and scope of the appended claims.

WE CLAIMS :-
1 An electroacoustical device comprising
a loudspeaker enclosure including a first acoustic port, an acoustic driver mounted in said loudspeaker enclosure, a heat producing device, heating surround air, and causing a convective airflow, said acoustic driver and said acoustic port constructed and arranged to coact to provide a cooling substantially unidirectional airflow in substantially the same direction as said convective airflow across said heat producing device thereby transferring heat from said heat producing device
2 An electroacoustical device in accordance with claim 1, wherein said loudspeaker
enclosure further includes a second acoustic port,
said heat producing device positioned in said enclosure,
said first acoustic port, said second acoustic port, and said acoustic driver constructed and arranged to coact to provide a substantially unidirectional cooling airflow across said heat producing device, thereby transferring heat from said heat producing device
3 An electroacoustical device in accordance with claim 1, and further composing an
airflow passage outside said loudspeaker enclosure,
said heat producing device positioned in said airflow passage
4 An electroacoustical device comprising
an acoustic enclosure,
a first acoustic port in said acoustic enclosure,
an acoustic driver mounted in said acoustic enclosure for causing a first airflow m said first acoustic port,
said first airflow alteraatingly inward and outward of said enclosure,
a heat producing device,
wherein said acoustic port is constructed and arranged so that said first airflow creates a substantially unidirectional second airflow, and
structure for directing said unidirectional second airflow across said heat producing device
5 An electroacoustical device in accordance with claim 4 and further comprising
a second acoustic port constructed and arranged to coact with said first acoustic port to provide said second airflow
6 An electroacoustical device, in accordance with claim 5 and further comprising
an airflow passage outside said acoustic enclosure for directing said second
airflow
7 A loudspeaker enclosure having an interior and an exterior, comprising
a first port having a first end having a cross-sectional area and a second end
having a cross-sectional area,
wherein said first end cross sectional area is greater than said second end cross-sectional area with said first end abuts said intenor and said second end abuts said
extenor; and
a second port located above said first port
8 A loudspeaker enclosure in accordance with claim 7,
wherein said second port has a first end having a cross-sectional area and a second end having a cross-sectional area with said first end cross sectional area larger than said second end cross-sectional area, and wherein said second end abuts said mtenor and said first end abuts said extenor
9 A loudspeaker enclosure in accordance with claim 7 and further compnsmg a mounting point for at least one heat producing device located below said second port
10 A loudspeaker enclosure in accordance with claim 9 wherein said mounting pomt is constructed and arranged for mounting an acoustic dnver
11 A loudspeaker system compnsmg
an electroacoustical transducer;
a loudspeaker enclosure having a first port having an intenor end and an extenor
end, said interior end and said exterior end each having cross-sectional area,
wherein said exterior end cross-sectional area is larger than said mtenor end
cross-sectional area, and
a second port having an mtenor end and an extenor end, wherein said first port is
located above said second port
12 A loudspeaker system in accordance with claim 11 wherein said second port
mtenor end and said second port extenor end each has a cross-sectional area,
wherein said second port mtenor end cross-sectional area is larger than said second port extenor end cross-sectional area
13 A loudspeaker system in accordance with claim 11, wherem said electroacoustical transducer is positioned m said loudspeaker enclosure higher than said first port and lower than said second port
14 A loudspeaker enclosure having a top and a bottom compnsing-
a first port having an mtenor end and an extenor end, each of said first port mtenor end and said first port extenor end having a cross-sectional area,
wherein said first port mtenor end cross-sectional area is smaller than said first port extenor end cross-sectional area,
a second port having an mtenor end and an extenor end,
each of said second port mtenor end and said second port extenor havmg a cross-sectional area,
wherein said second port mtenor cross-sectional area is larger than said second port external cross-sectional area
15 A loudspeaker enclosure in accordance with claim 14, wherein said first port exterior cross-sectional area is positioned closer to said top than said second port interior cross-sectional.
16 A loudspeaker enclosure in accordance with claim 14 and further comprising an opemng for an electroacoustical transducer positioned above said first port interior end and said second port intenor end
17 An electroacoustical device for operating in an ambient environment comprising
an acoustic enclosure comprising a port having an exit for radiating pressure
waves,
an electroacoustical transducer positioned in said acoustic enclosure,
said electroacoustical transducer for vibrating to produce said pressure waves,
a second enclosure having a first opening and a second opemng;
wherein said port exit is positioned near said first opemng so that said pressure waves are radiated into said second enclosure through said first opemng,
and wherein said port exit,
said first opemng, and said enclosure are constructed and arranged to cause air from said ambient environment to flow into said second enclosure through said first opemng,
a mounting position for a heat producing device in said second enclosure positioned so that air flowmg into said second enclosure through first opemng from said ambient environment flows across said mounting position
18 An electroacoustical device in accordance with claim 17 and further comprising a heat producing element mounted at said mounting position
19 An electroacoustical device in accordance with claim 18 wherein said heat producmg element is an audio amplifier
20 An electro-acoustical device, comprising
a first enclosure comprising a port having a terminal point for an outward airflow to exit said enclosure to an ambient environment and for an mward airflow to enter said
enclosure,
an electroacoustical transducer comprising a vibratile surface for generating
pressure waves resulting in said outward airflow and said inward airflow,
a second enclosure compnsing a first opening and a second opening,
wherein the port terminal point is positioned near said first opening and oriented
so that said port terminal outward flow flows toward said second opemng and wherein
said port and said electroacoustical transducer coact to cause a substantially
unidirectional airflow to flow into said first opemng
21 An electroacoustical device for operating in an ambient environment compnsing.
an acoustic enclosure compnsing a port having an exit for radiating pressure
waves,
an electroacoustical transducer positioned in said acoustic enclosure,
said electroacoustical transducer for vibrating to provide said pressure waves,
an elongated second enclosure having a first extremity and a second extremity in
a direction of elongation,
a first opemng at said first extremity and a second opemng at said second
extremity,
wherein said port exit is positioned in said first opening so that said pressure
waves are radiated into said second enclosure through said first opening toward said
second opemng, and
a mounting position for a heat producing device in said elongated second
enclosure positioned so that air flowing into said opemng from said ambient environment
flows across said mounting position
22 An electroacoustical device in accordance with claim 21, further compnsing a heat producing element mounted at said mounting position
23 An electroacoustical device in accordance with claim 22 wherem said heat producmg element is an audio amplifier
24 An electroacoustical device, compnsing
a first enclosure compnsing a port having a terminal point for an outward airflow to
exit said enclosure and for an inward airflow to enter said enclosure,
an electroacoustical transducer comprising a vibratile surface mounted in said first
enclosure for generating pressure waves resulting in said outward airflow and said inward
airflow,
a second enclosure comprising a first opening and a second opening,
wherein said port terminal point is positioned in said second enclosure and oriented
so that said port terminal outward airflow flows toward said second opemng and wherem said
port and said electroacoustical transducer coact to cause a substantially umdirectional airflow
into said first opemng
25 An electroacoustical device in accordance with claim 1 wherem said acoustic port is
formed with a vent and further comprising,
an acoustic element communicating with said vent and coacting therewith to introduce damping acoustic impedance into said acoustic port that reduces the standing wave amplitude in said acoustic port for at least one predetermined wavelength
26 A loudspeaker enclosure having a port tube, said port tube formed with a vent and
further comprising,
an acoustic element communicating with said vent and coactmg therewith to introduce damping acoustic impedance into said port that reduces the standmg wave amplitude in said port for at least one predetermined wavelength, and,
acoustic damping material positioned in said acoustic element
27 An electroacoustical device substantially as hereinbefore described
with reference to the accompanying drawings
28 A loudspeaker system substantially as hereinbefore described
with reference to the accompanying drawings.