Tubular loudspeaker

Provided is an acoustic loudspeaker comprising an enclosure and at least first and second loudspeaker drivers. The enclosure comprises at least one tubular sound channel of a substantially constant inside dimension acoustically coupled to the at least first and second loudspeaker drivers. The at least one tubular sound channel comprises a first opening disposed at a first end of the at least one tubular sound channel, a second opening disposed at a second end of the at least one tubular sound channel and a third opening disposed on the at least one tubular sound channel between the first and second ends. The second opening comprises a sound outlet for outputting sound conducted through the enclosure. The enclosure further comprises at least one tuning section disposed within the at least one tubular sound channel between the second and third openings.

FIELD OF THE DISCLOSURE

The present invention relates to a loudspeaker. More particularly, the present invention relates to a tubular loudspeaker.

BACKGROUND OF THE DISCLOSURE

A loudspeaker is an electromechanical device that converts an electrical signal into sound. There are numerous types of conventional loudspeakers. Among the more common type of loudspeakers, is a loudspeaker comprising a driver that is coupled to an enclosure and/or baffle. The driver vibrates in response to an electrical signal, thereby producing front and rear sound waves. Some drivers are specifically designed to reproduce the sound for a particular range of frequencies. For example, some drivers are designed to produce mid or low frequencies while others are designed to reproduce the upper frequency range. Often these various drivers are used together in a single loudspeaker. When used together, these various drivers may be augmented through the use of crossover electronic elements, serving to divide the frequencies sent to each driver from an input source. The purpose of the enclosure or baffle is to provide a mounting area as well as separate the front and rear sound waves to provide a usable and wide frequency response. Without an enclosure or large baffle, the front and rear sound waves will combine destructively, making the output sound, particularly in the low frequencies, virtually inaudible. It is therefore then the goal of the loudspeaker enclosure to control the front and rear waves such that they combine in a constructive fashion, reinforcing frequencies and output sounds that are not reproduced by one wave or the other exclusively, or not combine at all.

One type of loudspeaker implements a “finite baffle” design. In a “finite baffle” design, direct radiating loudspeakers are mounted to a surface facing the listening position. The finite baffle is a board or similar structure, typically of several meters in width and height, to which the loudspeaker is affixed. The finite baffle is used to separate the front and rear waves of the loudspeaker. A loudspeaker based on a finite baffle design is a non-resonant design, whereby the air propagation of the cone is not harnessed in an enclosure, and the air volume of the enclosure is not utilized to damp the cone of the loudspeaker. Nevertheless. This design is noted for producing an open sound, but is limited in power handling, sound pressure (decibel) output, and excessive size, In addition, this design can only be fully realized indoors, and is strongly reliant on the effect of room placement and coupling.

Another type of loudspeaker separates the front and rear sound waves by virtue of a sealed enclosure, wherein the rear wave is confined within the enclosure, serving to reinforce the cone of the driver acting as an air spring. This is often called acoustic suspension or the “infinite baffle”. This compact design, while easy to build and tune, is notoriously inefficient, limits low bass frequencies. This design can produce unwanted panel resonances or reflections within the enclosure that can be reflected back through the driver as well as non-linearities in the driver itself caused by the high air pressure changes in the enclosure. Other designs include the features of the acoustic suspension, but use an enclosure opening (port) sometimes including a tube or slot (a Helmholtz resonator) or a passive radiator driver to reinforce the front wave, allowing low frequencies to emanate from the port or radiator and dampen the driver at its resonance frequency. The tuning of these enclosures is known and can be reproduced through a defined formula. These designs are limited in producing a free and natural bass response, especially in the upper and mid bass regions, and produce unwanted panel resonances and standing waves. Still another design is set forth in U.S. Pat. No. 4,628,528 to Bose et al. suggests a waveguide enclosure (transmission line) whose length is determined by a formula of ¼ the wavelength of the chosen driver's resonance frequency, is designed as a labyrinth, and is typically constructed with an average cross sectional area 1.5-3.0 times the size of the driver. Extensive acoustical stuffing material is utilized for tuning purposes. The purpose of “stuffing” is to destroy unwanted high and middle frequencies from emanating from the rear wave and out an enclosure opening (port), where only low frequencies will exit, and recombine constructively with the front wave. “Stuffing”, however; creates manufacturing problems related to repeatability, loss of efficiency, and tuning reliability issues if the stuffing moves inside the enclosure. U.S. Pat. No. 6,700,984 to Holberg et al. suggests that the use of a transmission line enclosure with non-linearly tapering walls, with largest diameter near the driver and smallest diameter near the enclosure opening. It also recommends tuning based on U.S. Pat. No. 4,628,528 to Bose et al., discussed above, wherein the length of the enclosure is determined initially by a ¼ wavelength of the desired tuning frequency, with final tuning done by adding acoustical fibers (stuffing) packed into the enclosure. This design has numerous acoustical advantages over the aforementioned designs, one being the elimination of panel resonances reflecting from the enclosure and back through the driver itself, which can produce unwanted distortion and phasing issues.

All of these designs call for a front baffle with diameter or area greater than the area of the driver itself. Inherent with a baffle is baffle losses, produced when the front sound wave bounces off the enclosure and/or the enclosure sides and is projected towards the listener, out of phase with the desired sound wave. Baffles can also limit, filter, and/or destruct the output of certain frequencies measured “off axis,” most commonly 30 degrees to either side of the reference loudspeaker. The published work of engineer H. F. Olson from around 1969 is often referenced for baffle diffraction effects. The results of the research suggests the use of baffles shaped as spheres or enclosure sides progressively angled away from the driver and avoiding any 90 degree angles. All of his examples assume the baffle is substantially greater in area than the actual width of the drivers themselves, however.

Loudspeakers by their very nature are compromises; with no one design embodying all of the desired characteristics of the listener. It is therefore the object of this invention to improve upon existing and previously discussed prior art. Accordingly, there is a need for an improved loudspeaker that overcomes the above disadvantages.

SUMMARY OF THE DISCLOSURE

Exemplary embodiments of the present invention address at least the above problems and/or disadvantages and provide at least the advantages described below. Accordingly, an aspect of the present invention is to provide an acoustic loudspeaker comprising an enclosure and at least first and second loudspeaker drivers, the at least first and second loudspeaker drivers being substantially identical. The enclosure comprises at least one tubular sound channel of a substantially constant inside dimension acoustically coupled to the at least first and second loudspeaker drivers, wherein the at least one tubular sound channel comprises a first opening disposed at a first end of the at least one tubular sound channel, a second opening disposed at a second end of the at least one tubular sound channel and a third opening disposed on the at least one tubular sound channel between the first and second ends, wherein the first, second and third openings comprise an inner dimension which substantially corresponds to the inside dimension of the at least one tubular sound channel and the outside dimension of the at least first and second loudspeaker drivers, wherein the at least first and second loudspeaker drivers are coupled to the first and third openings, wherein the second opening comprises a sound outlet for outputting sound conducted through the at least one tubular sound channel from the at least first and second loudspeaker drivers. The enclosure further comprises at least one tuning section disposed within the at least one tubular sound channel between the second and third openings, the at least one tuning section running substantially parallel to the at least one tubular sound channel, wherein the at least one tuning section comprises an inside dimension that is less than the inside dimension of the at least one tubular sound channel.

Another aspect of the present invention is to provide an acoustic loudspeaker comprising and enclosure and at least first and second loudspeaker drivers, the at least first and second loudspeaker drivers being substantially identical. The enclosure comprises at least one tubular sound channel of a substantially constant inside dimension acoustically coupled to the at least first and second loudspeaker drivers, wherein the at least one tubular sound channel comprises a first opening disposed at a first end of the at least one tubular sound channel, a second opening disposed at a second end of the at least one tubular sound channel and a third opening disposed on the at least one tubular sound channel between the first and second ends, wherein the first, second and third openings comprise an inner dimension which substantially corresponds to the inside dimension of the at least one tubular sound channel and the outside dimension of the at least first and second loudspeaker drivers, wherein the at least first and second loudspeaker drivers are coupled to the first and third openings, wherein the second opening comprises a sound outlet for outputting sound conducted through the at least one tubular sound channel from the at least first and second loudspeaker drivers.

Another aspect of the present invention is to provide an acoustic loudspeaker comprising an enclosure and at least a first loudspeaker driver. The enclosure comprises at least one tubular sound channel of a substantially constant inside dimension acoustically coupled to the at least first loudspeaker driver, wherein the at least one tubular sound channel comprises a first opening disposed at a first end of the at least one tubular sound channel and a second opening disposed at a second end of the at least one tubular sound channel, wherein the first and second openings comprise an inner dimension which substantially corresponds to the inside dimension of the at least one tubular sound channel and the outside dimension of the at least first loudspeaker driver, wherein the at least first loudspeaker driver is coupled to the first opening, wherein the second opening comprises a sound outlet for outputting sound conducted through the at least one tubular sound channel from the at least first loudspeaker driver. The enclosure further comprises at least one tuning section disposed within the at least one tubular sound channel between the first and second openings, the at least one tuning section running substantially parallel to the at least one tubular sound channel, wherein the at least one tuning section comprises an inside dimension that is less than the inside dimension of the at least one tubular sound channel.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

FIGS. 1-3illustrate a cross-sectional view of a loudspeaker according to various exemplary embodiments. Each of the exemplary embodiments of loudspeaker10, at the least, comprise driver20and enclosure30. Enclosure30, at the least, comprises various sections including a linear sound channel32, input curvilinear sound channel34, output curvilinear sound channel36and sound opening38. For the sake of brevity, at least a portion of the features that are common in the exemplary embodiments shown inFIGS. 1-3are discussed below.

As illustrate inFIGS. 1-3, enclosure30may be substantially tubular with a substantially constant inside dimension ‘x’ throughout its various sections, including linear sound channel32, input curvilinear sound channel34, output curvilinear sound channel36, and sound opening38. The cross-sectional tubular shape of enclosure30may be square, elliptical, circular, triangular or any other shape that can be used to form a tube. In other embodiments, enclosure30is any structure that is formed with sound channels that have a substantially constant inside dimension ‘x’, wherein the sound channels are effectively equivalent to sound channels formed by a tubular enclosure. Inside dimension ‘x’ may be any of a diameter, cross-sectional area, width, or any other dimension. The use of a tubular shape for the sound channels serves to minimize unwanted panel related resonances within the enclosure.

The total length of the sound channel of enclosure30is defined as the length of a line running through the center of enclosure30from sound opening38to the opening in enclosure30to which driver20is mounted. It is preferred that the length of the sound channel of enclosure30be about 8-12 times the inside dimension ‘x’. Further, it is preferred that any curvilinear sound channels be formed with a smooth radius as shown by example inFIGS. 1-3. In addition, in some embodiments, adjacent sections of enclosure30may share at least a portion of a common wall.

The structures illustrated inFIGS. 1-3for enclosure30are merely exemplary embodiments for enclosure30. It would be apparent to one of skill in the art that variations to the location, lengths and number of linear sound channels and the location, radius and number of curvilinear sound channels may be made within the scope of the embodiments of the present inventions. For example,FIG. 4illustrates an exemplary structure for loudspeaker10that includes an additional curvilinear sound channel37of about 180 degrees that is disposed near the midpoint of enclosure30.

Enclosure30may be constructed in one of various ways. In one embodiment, enclosure30may be constructed of plural sections that are mated together by glue, friction fitted, clamped, screwed, or held together by any other manner of retaining two structures together. For example, the plural sections may be conventional PVC pipe sections that are frictionally and removably coupled together. In another embodiment, enclosure30may be formed as two clamshells that are mated together. In yet another embodiment, enclosure30may be formed as a single body in either tubular form or with the sound channels formed within.

Drivers, such as driver20inFIGS. 1-3and drivers21inFIGS. 2 and 3, are mounted at an open end of a sound channel so as to be mechanically and acoustically coupled to enclosure30such that substantially all sound emerging from the back side of driver20is captured by enclosure30. The captured sound propagates along path ‘p’, passing though tuning section40, before exiting to free atmosphere through sound opening38.

While the choice of a driver depends on the desired size and characteristics of loudspeaker10, as would be apparent to one of ordinary skill in the art, it is preferred that driver selection be made within the constraints discussed below. Preferably,

the driver(s) may be one of a full range, midrange, mid-bass, bass, or subwoofer driver as is known in the art. It is preferred that the driver(s) be selected such that it has substantially the same shape as the cross-sectional tubular shape used for the sound channels in enclosure30. Further, it is preferred that the driver(s) be selected such that its dimension is substantially the same as the inside dimension ‘x’ of enclosure30.

Preferably, the tubular enclosure walls of enclosure30extend away from driver20, in an opposite direction to the front of the driver(s), a sufficient distance so as to substantially minimize the tubular enclosure walls of enclosure30from acting as a baffle. Accordingly, enclosure30is structured such that sound produced from the front of the driver(s) is not substantially reflected and deflected off the exterior of the tubular enclosure walls of enclosure30, thereby enhancing off axis sound level response.

In some embodiments, an annular deflecting ring (not shown) is disposed at about, and extends away from, the junction between the driver(s) and the open end of the sound channel where the driver(s) are mounted. Preferably, as the annular deflecting ring extends away from the junction between the driver(s) and the open end of curvilinear sound channel34where the driver(s) are mounted, the surface of annular deflecting ring closest to the driver(s) smoothly curves away from the driver(s). The cross sectional shape of the curve may be may be linear, exponential, hyperbolic, parabolic, a “tractrix” or any combination thereof. In addition, the cross sectional shape may be any other type of or combination of types of curves or shapes. In some embodiments, the annular deflecting ring is integral to enclosure30. Further, in other embodiments, the inside dimension of the open end of a sound channel where the driver(s) are installed may be larger than dimension ‘x’ in the area adjacent to the driver(s).

Preferably, sound opening38is oriented in that same direction as the front of driver20, as shown inFIG. 1. Further it is preferred that sound opening38be located in that same plane as the driver(s). However, in other embodiments, sound opening38may be oriented in any other direction and lie in any other plane. Further, while it is preferred that sound opening38be substantially baffle-less in a similar manner to that discussed above with respect to driver20, sound opening38in some embodiments may be implemented with a baffle, horn or an annular deflective ring. Still further, sound opening38may be fitted with a passive radiator.

Preferably, a least a portion of the interior walls of the enclosure are lined with a fibrous sound-absorbing material of approximately ¼-½ inch in thickness. In some embodiments, enclosure30is at least partially stuffed with fibrous sound-absorbing material at approximately ½ pound per cubic foot of volume. In still other embodiments, one or more sections of enclosure30may be stuffed with fibrous sound-absorbing material while one or more other sections may be lined with the fibrous sound-absorbing material. In the embodiments where at least a portion of enclosure30is stuffed with the fibrous sound-absorbing material, varying the amount of fibrous sound-absorbing material may vary the tuning of enclosure30. Accordingly, if enclosure30is to be at least partially tuned by varying the amount of fibrous sound-absorbing material stuffed in enclosure30, it is preferred that the amount of sound-absorbing material be determined by trial and error. The fibrous sound-absorbing material when stuffed or lined serves as a transmission medium for assisting in the projection of lower frequency audible sound through enclosure30. The fibrous sound-absorbing material when stuffed or lined also dampens any possible resonance generated and attenuates higher frequencies. The fibrous sound-absorbing material may be formed of polyester, nylon, fiberglass or any other sound-absorbing material.

In some other embodiments, sound opening38and/or the driver(s) may include a grill formed of a sound penetrable material such as a decorative metal screen. When implemented with sound opening38a grill is adapted for preventing any extraneous materials from entering enclosure30through sound opening38and may prevent any sound-absorbing material from leaving enclosure30through sound opening38. When implemented with the driver(s), a grill operates as a protective barrier.

WhileFIGS. 1-3illustrate the preferred orientation for loudspeaker10, loudspeaker10may be oriented in any other manner, such as horizontally or at an angle In some embodiments, all or a portion of enclosure30may be fitted within a decorative enclosure and/or wall. Further, enclosure30may be fitted with a mounting member for mounting enclosure30to a support bracket. Still further enclosure30may be fitted with a crossover and/or amplifier that is electrically coupled to driver20. In addition, wiring for energizing the driver20is at least partially routed through enclosure30.

While some features that are common to the exemplary embodiments shown inFIGS. 1-3have been discussed above, not all features that are common have been discussed above and not all features discussed above are common to all of the exemplary embodiments. The exemplary embodiments illustrated inFIGS. 1-3will now be discussed below.

FIG. 1illustrates a cross-sectional view of a loudspeaker according to an exemplary embodiment. As shown inFIG. 1, loudspeaker10consists of a driver20and enclosure30. Enclosure30comprises various sections including a linear sound channel32, input curvilinear sound channel34, output curvilinear sound channel36and sound opening38. A tuning section40is disposed within enclosure30. Hereafter, the portion of linear sound channel32between input curvilinear sound channel34and tuning section40will be referred to as first linear sound channel32aand the portion of linear sound channel32between tuning section40and output curvilinear sound channel36will be referred to as second linear sound channel32b.

Herein, in the exemplary embodiment illustrated inFIG. 1, the captured sound from driver20propagates along path ‘p’, passing though tuning section40, before exiting to free atmosphere through sound opening38.

Tuning section40is disposed within enclosure30between driver20and sound opening38. As shown inFIG. 1, tuning section40comprises a linear tuning channel42of length ‘l’ with a constant inside dimension ‘y’, wherein inside dimension ‘y’ is less than inside dimension ‘x’ of linear sound channel32. Further, tuning section40may includes a holding member44that supports linear tuning channel42within enclosure30. Holding member44and linear tuning channel42may be constructed of separate components or formed as a single component. Further, tuning section40may be separately formed from enclosure30or internally formed therewith. Holding member44acoustically isolates first linear sound channel32afrom second linear sound channel32bin the space between the enclosure30and the linear tuning channel42. Accordingly, first linear sound channel32aand second linear sound channel32bare acoustically coupled through linear tuning channel42.

Preferably, the inside dimension ‘y’ of linear tuning channel42is about ½ to ⅔rd of the inside dimension ‘x’ of linear sound channel32. Further, it is preferred that the length of linear tuning channel42be about ⅕thto 1/10th the total length of enclosure30. Still further, it is preferred that the portion of linear tuning channel42closest to driver20be disposed at about the midpoint of enclosure30. When loudspeaker10is properly tuned it will exhibit lower distortion and a flatter impedance. It is difficult to form a mathematical model for tuning enclosure30so a trial and error methodology may be implemented for tuning enclosure30. In embodiments where fibrous sound-absorbing material is at least partially stuff in enclosure30, tuning is further carried out by adjusting the amount of fibrous sound-absorbing material that is stuffed in enclosure30.

The tuning section40depicted inFIG. 1is merely one example of various embodiments for the structure for tuning section40. For example, while mounting member44is illustrated inFIG. 1as being disposed at one end of the linear tuning channel42, in some embodiments mounting member44may be disposed at any other position along linear tuning channel42, such as in the middle of linear tuning channel42, as depicted inFIG. 5. Further, while mounting member44is depicted as being relatively thin in comparison to the length ‘l’ of the linear tuning channel42, mounting member44may be any thickness up to length ‘l’ of linear tuning channel42, as shown inFIG. 6. Still further, tuning section40may be formed using a plurality of linear tubes42, as shown inFIG. 7. In addition, tuning section40may be tapered with one end having substantially the same dimension ‘x’ of linear sound channel32and the other end having inside dimension ‘y,’ as shown inFIG. 8. The tapering may be linear, exponential, hyperbolic, parabolic, a “tractrix” or any combination thereof. In addition, the tapering may be any other type or combination of types of tapering. Further, while a tapered tuning section40may be installed in either direction within enclosure30, it is preferred that tuning section40be oriented such that the larger end of a tapered tuning section40is closer to driver20.

In some embodiments more than one tuning section40is disposed within enclosure30. When more than one tuning section40is disposed within enclosure30, any number of the more than one tuning sections40may be different from or identical to one another.

In other embodiments, one or more passive radiators and/or additional drivers may be implemented in addition to or substituted for tuning section40within enclosure30. When used with tuning section40, the one or more passive radiators and/or additional drivers may be disposed in either one or both of first linear sound channel32aand second linear sound channel32b. When an additional driver is used it is preferred that the additional driver be substantially identical to driver20.

In operation, when driver20is electrically energized, it emits sounds that are forwardly propagated as well as back propagated through enclosure30. The sounds are back propagated through enclosure30, passing through tuning section40, before being projected from sound opening38substantially in phase with the sound forwardly projected from the driver20. The implantation of tuning section40improves the bass response while reducing the enclosure size and/or length. Further, the use of tuning section40reduces the need for stuffing of the enclosure with acoustic fiber fill material and the related losses and tuning problems associated with same. Accordingly, tuning section40may simplify the tuning of enclosure30. Also, because of the substantially synchronous phasing generated through the tubular enclosure, audible sound transmission is essentially distortion free with greater extension. Further, by not implementing a conventional baffle, baffle losses are avoided.

FIG. 2illustrates a cross-sectional view of a loudspeaker according to another exemplary embodiment. As shown inFIG. 2loudspeaker10consists of a driver20, additional driver21and enclosure30. Enclosure30comprises various sections including a linear sound channel32, input curvilinear sound channel34, additional input curvilinear sound channel35, output curvilinear sound channel36and sound opening38.

As illustrate inFIG. 2, enclosure30includes additional input curvilinear sound channel35, which is disposed between driver21and linear sound channel32. The additional input curvilinear sound channel35is disposed on linear sound channel32between driver20and sound opening38. Additional input curvilinear sound channel35is disposed on linear sound channel32such that the distance between driver21and sound opening38through the sound channel in enclosure30is approximately ⅝ to ⅞ the distance between driver21and sound opening38through the sound channel in enclosure30. Additionally input curvilinear sound channel35, like the other portions of enclosure30, comprises substantially constant inside dimension ‘x’. Further, it is preferred that driver20and driver21be substantially identical. The use of at least two drivers with enclosure30increases the level of sound output from enclosure30.

While the embodiment illustrated inFIG. 2reflects the preferred number, type and arrangement of drivers, it would be apparent to one of skill in the art that variations to the number, type and arrangement of drivers could be made within the scope of the embodiments of the present inventions. For example, more than two drivers and respective sound channels may be implemented as long as all of the drivers are substantially identical to one another. Accordingly, an array of drivers may be implemented using an single enclosure30by adding combinations of a driver and input curvilinear sound channel along linear sound channel32.

In operation, when driver20and driver21are electrically energized, they emits sounds that are forwardly propagated as well as back propagated through enclosure30. The sounds back propagated through enclosure30are projected from sound opening38substantially in phase with the sound forwardly projected from the driver20. The suggested arrangements of the drivers20and21and the path of the directed sound waves have the net effect of shortening the required length or volume of the enclosure12while providing maximum acoustical benefits, including the likelihood of providing addition destruction of upper and mid frequencies from reaching sound opening38. Also, because of the substantially synchronous phasing generated through the tubular enclosure, audible sound transmission is essentially distortion free with greater extension and decibel output. Further, by not implementing a conventional baffle, baffle losses are minimized or avoided.

FIG. 3illustrates a cross-sectional view of a loudspeaker according to yet another exemplary embodiment. As shown inFIG. 3loudspeaker10consists of a driver20, additional driver21and enclosure30. Enclosure30comprises various sections including a linear sound channel32, input curvilinear sound channel34, additional input curvilinear sound channel35, output curvilinear sound channel36and sound opening38. A tuning section40is disposed within enclosure30. The portion of linear sound channel32between input curvilinear sound channel34and tuning section40will be referred to as first linear sound channel32aand the portion of linear sound channel32between tuning section40and output curvilinear sound channel36will be referred to as second linear sound channel32b.

The exemplary embodiment illustrated inFIG. 3includes tuning section40discussed above with respect toFIG. 1. Further, exemplary embodiment illustrated inFIG. 3includes additional driver21and additional input curvilinear sound channel35discussed above with respect toFIG. 2. Accordingly, explanation of the tuning section40, additional driver21and additional input curvilinear sound channel35will not be repeated below.

As illustrated inFIG. 3, tuning section40is preferably disposed between additional input curvilinear sound channel35and sound opening38. However, in other embodiments, tuning section40is disposed between input curvilinear sound channel34and additional input curvilinear sound channel35. In yet other embodiments, any number of combinations of driver and input curvilinear sound channel may be implemented above and/or below tuning section40.

In operation, when driver20and driver21are electrically energized, they emit sounds that are forwardly propagated as well as back propagated through enclosure30. The sounds are back propagated through enclosure30, passing through tuning section40, before being projected from sound opening38substantially in phase with the sound forwardly projected from the driver20. The embodiment illustrated inFIG. 3combines many of the features of the embodiments illustrated inFIGS. 1 and 2and therefore experiences many of the same benefits. For example, the implantation of tuning section40improves the bass response while reducing the enclosure size and/or length. Further, the use of tuning section40reduces the need for stuffing of the enclosure with acoustic fiber fill material and the related losses and tuning problems associated with same. Accordingly, tuning section40may simplify the tuning of enclosure30.

Also, the suggested arrangements of the drivers20and21, the path of the directed sound waves and the arrangement of the tuning section40have the net effect of shortening the required length of the enclosure12while providing maximum acoustical benefits. Additionally, because of the substantially synchronous phasing generated through the tubular enclosure, audible sound transmission exhibits reduced distortion, greater extension, and increased decibel output. Further, by not implementing a baffle, baffle losses are avoided.

FIG. 9illustrates a perspective view of an exemplary commercial embodiment of loudspeaker10implementing the embodiment illustrated inFIG. 3. The features discussed above with respect toFIGS. 1-3are equally applicable to the embodiment shown inFIG. 9. Accordingly, descriptions of such features will be omitted from the discussion below.

As can be seen inFIG. 9, loudspeaker10is fitted with high frequency driver50that is mechanically but not acoustically coupled to enclosure30. The particular implementation of the drivers20,21and50illustrated in loudspeaker10is merely exemplary. In the embodiment illustrated inFIG. 9, drivers20,21and50are configured as a 2-way D'Appolito array wherein drivers20and21are substantially low frequency drivers and driver50is a high frequency driver. Further, a stand60is illustrated inFIG. 9as supporting loudspeaker10. This stand is merely exemplary as any other mounting or supporting structure may be used with load speaker10.

InFIG. 9, each of the drivers20,21and50are oriented in substantially the same direction toward the primary listening area. However, in other embodiments the drivers20,21and50may be arranged such that they any number of them are oriented in different directions. For example, the drivers20,21and50may be arranged in a dipole or tripole arrangement as is known in the art. Further, while it is preferred that sound opening50be oriented toward the primary listening direction, sound opening50may alternately be oriented in any other direction as discussed above. Further, drivers20,21and50and sound opening38are illustrated as being disposed on the same plane. However, any of drivers20,21and50and sound opening38may alternatively be disposed on differing planes, such as planes that are parallel to one another.

In some embodiments additional drivers may be mechanically but not acoustically coupled to enclosure25. For example, midrange drivers (not shown) could be disposed between driver20and driver50and between driver50and driver21respectively. In this embodiment, the drivers are configured as a 3-way D'Appolito array. In these embodiments drivers20and21remain the only drivers acoustically coupled to enclosure30. Still further, the midrange drivers could alternatively be disposed on either side of high frequency driver50so as to not be located between driver20and driver50and between driver50and driver21.

FIG. 10illustrates a perspective view of an exemplary commercial embodiment of loudspeaker10implementing the embodiment illustrated inFIG. 4. The features discussed above with respect toFIGS. 1-3and9are equally applicable to the embodiment shown inFIG. 10. Accordingly, descriptions of such features will be omitted.FIG. 10illustrates a different exemplary embodiment for drivers20,21and50and stand60than those depicted inFIG. 9.

A single loudspeaker10may be used to reproduce monaural sound or a pair of loudspeakers10may be utilized together for stereo reproduction, one for the left and right channels. Still further, a plurality of loudspeakers10may be used for multi-channel or surround sound reproduction.