Motorcycle speaker system

A motorcycle having an open-air cockpit area and a seat configured to receive a rider and position the rider within the open-air cockpit area. A luggage container defines a substantially enclosed cargo volume, and the luggage container is configured to open to provide selective access to the cargo volume. A speaker is configured to output sound in response to signals from a source. A speaker enclosure at least partially encloses the speaker. A bass-reflex passage couples an interior space of the sparker enclosure and the cargo volume of the luggage container.

BACKGROUND

The present invention relates to audio systems for motorcycles. More particularly, the invention relates to a motorcycle speaker arrangement with improved bass response.

Many motorcycle riders, especially those that ride touring motorcycles to travel long distances, prefer to have their motorcycles equipped with an audio system to provide music or another type of audio entertainment during the ride. To this end, original equipment and accessory audio systems have been available on the market for many years. However, some inherent drawbacks are faced by motorcycle audio systems. One drawback is that the substantially open-air atmosphere and significant traveling wind can make it more difficult for a rider to hear the output of the speakers. Additionally, space on a motorcycle is very limited, and therefore practical limits exist on the size of speakers and enclosures that can be mounted. These and other constraints make it difficult to provide high quality sound reproduction with satisfactory low frequency (bass) response.

SUMMARY

In one embodiment, the invention provides a motorcycle having an open-air cockpit area and a seat configured to receive a rider and position the rider within the open-air cockpit area. A luggage container defines a substantially enclosed cargo volume, and the luggage container is configured to open to provide selective access to the cargo volume. A speaker is configured to output sound in response to signals from a source. A speaker enclosure at least partially encloses the speaker. A bass-reflex passage couples an interior space of the speaker enclosure and the cargo volume of the luggage container.

In another embodiment, the invention provides a motorcycle including a rigid trunk having a substantially enclosed cargo volume. A speaker is configured to output sound in response to signals from a source. A speaker enclosure at least partially enclosing the speaker is positioned on an external surface of the trunk. A bass-reflex passage couples an interior space of the speaker enclosure and the cargo volume of the trunk.

In yet another embodiment, the invention provides a motorcycle having an open-air cockpit area and a seat configured to receive a rider and position the rider within the open-air cockpit area. A rigid trunk is positioned rearward of the open-air cockpit area and defines a substantially enclosed cargo volume. The trunk has a hinged lid configured to open to provide selective access to the cargo volume. A pair of speakers are configured to output sound in response to signals from a source. A left speaker enclosure is positioned on a left external side of the trunk and at least partially encloses a first one of the pair of speakers. A right speaker enclosure is positioned on a right external side of the trunk and at least partially encloses a second one of the pair of speakers. A first bass-reflex passage provides direct communication between an interior space of the left speaker enclosure and the cargo volume of the trunk. A second bass-reflex passage provides direct communication between an interior of the right speaker enclosure and the cargo volume of the trunk.

DETAILED DESCRIPTION

FIG. 1illustrates a motorcycle20including a front wheel24steerable by a handle bar28and a rear wheel32propelled by an engine36. The motorcycle20includes a seat40that positions a seated rider in an open-air cockpit44for operating the motorcycle20. Although the basic configuration of the illustrated motorcycle20is traditional, many aspects of the invention described in detail below are not dependent upon a traditional configuration and can be used with motorcycles of various other configurations including for example, those with two front wheels or two rear wheels. The illustrated motorcycle20is a touring style motorcycle and includes various luggage containers including a pair of saddlebags48positioned alongside left and right sides of the rear wheel32as well as a trunk52positioned rearward of the cockpit44along the motorcycle's longitudinal axis or centerline A (FIG. 4). In the illustrated construction, the trunk52is a Harley-Davidson TOUR-PAK® and is positioned directly behind a passenger-accommodating area56of the motorcycle20. However, it should be appreciated that many of the features described in detail below are not limited to use with a Harley-Davidson TOUR-PAK® and can be used with various motorcycle trunks or top cases.

Both the saddlebags48and the trunk52are constructed of rigid materials, such as plastic, fiberglass, etc. This is commonly known as “hard luggage” as opposed to “soft luggage”, which generally is constructed of leather, nylon, or other textiles and is generally compressible as opposed to hard luggage, which provides inherent rigidity. The illustrated trunk52includes a body52A and a lid52B that are coupled together with hinges. One or more latches are used to retain the lid52B in a closed position with respect to the body52A. When unlatched, the lid52B opens to provide selective access to a cargo volume jointly defined by the body52A and the lid52B.

Speaker enclosures60are positioned at each lateral side of the trunk52. As shown inFIG. 3, each speaker enclosure60is positioned on an external surface64of a side wall68of the trunk52and coupled to the side wall68with three fasteners72. In the illustrated construction, the side wall68is a front side wall of the trunk52, but one or more speaker enclosures can also be coupled to other side walls or other portions of the trunk52. Only one of the speaker enclosures60is shown inFIG. 3, but it should be understood that the other speaker enclosure60(and associated components) are formed as a mirror image. In the illustrated construction, a gasket76is positioned between the inboard side of the speaker enclosure60and the external surface64of the trunk52. The gasket76may be constructed of a suitable material, such as closed-cell foam, to provide an air-tight and water-tight seal when compressed between the speaker enclosure60and the external surface64of the trunk52. Although the illustrated construction places the speaker enclosures60on the side walls68of the trunk52, the speaker enclosures60may be positioned at other locations on the trunk52or additional speaker enclosures may be coupled to the trunk52in addition to the illustrated speaker enclosures60.

Each speaker enclosure60includes a speaker-receiving opening80into which a speaker84is received. In the illustrated construction, each speaker enclosure60receives a single speaker84, but alternate arrangements may be substituted. The speaker enclosure60includes a ridge88at the speaker-receiving opening80that receives an outer flange92of the speaker84. As shown inFIG. 3, a gasket96is positioned between the ridge88and the outer speaker flange92. The gasket96provides an air-tight and water-tight seal between the speaker84and the speaker enclosure60when compressed therebetween. Four fasteners100are used to couple the outer speaker flange92to the ridge88, thus mounting the speaker84in the speaker enclosure60. The speaker84is substantially enclosed within the interior of the speaker enclosure60with the front side of the speaker84directed at a desired outward angle.

With continued reference toFIG. 3, electrical wires108are used to connect the speaker84to a source (not shown), such as a music player or other audio output device that sends electrical signals to drive the speakers84. It should also be appreciated that the speakers84may be configured to receive signals and operate wirelessly. The electrical wires108are bundled and terminate in a harness112for ease of connectivity. Although described above as being configured for an external source, the speaker enclosure60can be provided with an internal source in addition to or instead of an external source if desired. The bundled wires108are covered in a wrap116and extend through an aperture120in the speaker enclosure60so that the wires108can be connected on one end to the rear side of the speaker84within the speaker enclosure60and on the other end to a source which is external to the speaker housing60. The wiring aperture120of the speaker enclosure60receives a form-fitting grommet124(e.g., a split-ring grommet). The grommet124has an aperture128in which the bundled and wrapped electrical wires108are form-fittingly received. Because the bundled and wrapped electrical wires108are tightly received within the grommet124, and the grommet124is tightly received within the wiring aperture120of the speaker enclosure60, the wiring aperture120is substantially sealed from the undesirable outward leakage of air during speaker operation and the undesirable inward seepage of water from the environment.

To enhance particularly the low frequency response of the speaker84, the speaker enclosure60is “ported”. More specifically, a bass-reflex passage is provided between the interior space of the speaker enclosure60and the cargo volume of the trunk52via cooperating apertures132,134formed in the side wall68of the trunk52and the speaker enclosure60, respectively. Although not required in all constructions, the apertures132,134have substantially the same shape (i.e., circular) and size. In some constructions, the apertures132,134are about 2.0 inches in diameter. In the illustrated construction, the gasket76between the speaker enclosure60and the external surface64of the trunk52is formed with a corresponding aperture138that is about the same size and shape as (or slightly larger than) the apertures132,134.

A hollow port142is positioned to establish direct communication between the interior space of the speaker enclosure60and the cargo volume of the trunk52. By “direct” it is meant that air or a sound pressure wave in air may pass between the interior space of the speaker enclosure60and the cargo volume of the trunk52without passing into the outside atmosphere or an interior space of any other component. In the illustrated construction, the hollow port142is generally cylindrical or tubular and includes a tubular shank146and an enlarged end flange150. The flange150is configured to abut an interior surface154of the trunk52. As shown inFIG. 6, the interior surface154is provided by a trunk liner158(the liner158is removed for clarity in the remaining figures). The liner158is sandwiched between the trunk side wall68and the flange150of the hollow port142in the illustrated construction. Alternately, the end flange150of the hollow port142may directly abut the side wall68of the trunk52.

The hollow port142is configured to be assembled by inserting from the interior side of the trunk52through the liner158, through the aperture132in the side wall68of the trunk52, through the aperture138in the gasket76, and through the aperture134in the speaker enclosure60. A snap-fit is enabled by a resilient ring162positioned on the shank146of the hollow port142. The resilient ring162has an outer diameter exceeding the diameters of the apertures132,134so that interference is present. The interference is overcome by compressing the resilient ring162radially inward when the hollow port142is inserted. Once the resilient ring162is pressed through the aperture134in the speaker enclosure60, the resilient ring162resiliently returns to its original form and holds the hollow port142from incidental disassembly. A screen164is positioned to extend across the hollow port142adjacent the end flange150. The screen164allows substantially free passage of air while preventing small objects (e.g., coins, etc.) within the trunk52from matriculating into the speaker enclosures60.

As shown inFIGS. 5 and 6, the shank146is formed with two axially-spaced channels166. Each of the channels166extends circumferentially about the shank146and is configured to receive and position the resilient ring162at a particular distance from the enlarged flange150. The resilient ring162can be moved between the two channels166to reconfigure the hollow port142to provide a suitable fit when used with the illustrated liner158or an alternate liner having a different thickness (or to provide a suitable fit when used with or without the liner158). Thus, the same hollow port142is easily reconfigurable by repositioning the resilient ring162to accommodate different liner configurations inside the trunk52.

Although the hollow port142is illustrated as being substantially tubular, the port can have alternate cross-sectional shapes including round (e.g., ovate, elliptical, etc.), angular (triangular, rectangular, etc.), or irregular cross-sectional shapes. Furthermore, the establishment of a bass-reflex passage, whether direct or indirect, is not dependent upon a dedicated port member (i.e., hollow port142) being provided. For example, the speaker enclosure60or the side wall68of the trunk52may be provided with a hollow protruding portion at the corresponding aperture132,134configured to extend into the aperture132,134of the other, or the apertures132,134in the trunk52and the speaker enclosure60may themselves establish the bass-reflex passage. Regardless of whether or not a dedicated port member is used, it should also be noted that more than one passage may establish direct communication between the interior space of each speaker enclosure60and the cargo volume of the trunk52to provide a desired bass-reflex effect.

FIG. 7illustrates an alternate speaker enclosure60′ including an aperture134′ that is irregular in shape and substantially larger than the aperture134shown inFIG. 6. The aperture134′ may match apertures in the side wall68of the trunk52and the liner158and may receive a similarly-shaped hollow port (not shown). However, in some constructions, at least one of the trunk52and the liner158may include an array of smaller apertures generally corresponding to the large, irregular aperture134′. In some such constructions, no hollow port member is used.FIGS. 8-10illustrate various exemplary patterns of small apertures that generally correspond to the circular aperture134of the speaker enclosure60. For example, apertures according to one of the illustrated patterns may be provided in both the side wall68of the trunk52and the liner158to cooperate with the aperture134to establish direct communication between the interior space of the speaker enclosure60and the cargo volume of the trunk52. Furthermore, the aperture134in the speaker enclosure60can also be replaced by a pattern of small apertures corresponding to those in the trunk52and the liner158, although this may complicate the assembly by requiring greater positional accuracy between the speaker enclosure60and the trunk52. AlthoughFIGS. 8-10illustrate particular patterns of circular holes, horizontal slots, and segmented circumferential slots of various diameters, alternate aperture patterns may be provided. The frequency response of the speaker84is tuned for a particular frequency response characteristic (e.g., a boost in sound pressure level over a particular frequency range) by the particular size and configuration of the passage(s) establishing communication between the interior space of the speaker enclosure60and the cargo volume of the trunk52.

By providing the direct communication between the interior space of the speaker enclosures60and the cargo volume of the trunk52, the sound pressure generated by the speakers84is allowed to reverberate through a significantly larger space than that provided by the speaker enclosures60alone. Meanwhile, the speaker enclosure-sealing components (i.e., the gaskets76,96and the grommet124) act to maximize the effective sound pressure by minimizing sound pressure leakage out of the speaker enclosures60. The sealing of the speaker enclosures60works in combination with the bass-reflex passage to markedly improve the low frequency (“bass”) response of the speakers84while reducing total harmonic distortion. For example, between about 50 Hz and about 200 Hz, the sound pressure level is increased by about 5-10 dB while the total harmonic distortion over the same frequency range is reduced from about 15-30 percent down to about 1-5 percent. Thus, not only is the sound level from the speakers84increased at the low frequencies, but the overall sound quality is improved.

While the trunk52is a convenient location for mounting the speaker enclosures60as described above, features and aspects of the arrangement described above can be adapted to speaker enclosures positioned on any luggage container provided on the motorcycle20. For example, speaker enclosures similar to the speaker enclosures60can be positioned on external surfaces of the saddlebags48. The interior space of such speaker enclosures can be substantially sealed from the environment and provided direct communication to a cargo space within the respective saddlebags48by a bass-reflex passage as described above. Likewise, one or more speaker enclosures can be positioned on glovebox-type luggage containers provided either in a cowl area (generally inside a 190 of the motorcycle20) or in leg shields or “lowers”194(FIG. 1). The interior space of such a speaker enclosure can be substantially sealed from the environment and provided direct communication to a cargo space within the corresponding glovebox-type container by a bass-reflex passage as described above.