Patent Publication Number: US-10313795-B1

Title: Vehicle audio system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application of U.S. patent application Ser. No. 15/920,998, filed Mar. 14, 2018, which is hereby incorporated by reference in its entirety. 
    
    
     BACKGROUND 
     This description relates to vehicle audio entertainment and communication systems, and, more particularly, to off-road vehicle sound systems. 
     At least some known vehicles include audio systems for entertainment, programming, communications, or other audio output. Known audio systems typically include at least one audio source, an amplifier, equalizer, and speakers mounted in the interior cabin of the vehicle. Some vehicles include acoustic exciters coupled to panels that form a part of the vehicle. The acoustic exciters and panels act as drivers and diaphragms similar to speakers. To produce high fidelity sound that includes the frequencies humans can perceive, an equalizer is typically used. However, an equalizer is an expensive piece of electronic equipment that adds weight and occupies room in the vehicle. 
     BRIEF DESCRIPTION 
     In one embodiment, a vehicle sound system includes one or more acoustic panel assemblies. Each of the one or more acoustic panel assemblies includes a sound panel formed of a material having a respective flexural modulus and an acoustic exciter coupled to each of the one or more sound panels. Each acoustic exciter is configured to receive a first audio signal containing a first frequency range. Each of the one or more sound panels is configured to generate a sound signal containing a respective range of sound pressure vibrations dependent on the flexural modulus of a material the sound panel is formed of, variations of dimensions of the sound panel, and the first audio signal received by the acoustic exciter coupled to the sound panel. 
     In another embodiment, a method of generating sound having a plurality of frequency responses includes receiving, by a plurality of acoustic exciters, a single audio signal that includes a plurality of frequency ranges. The plurality of acoustic exciters is coupled to a corresponding plurality of sound panels. Each sound panel is formed of a material having a predetermined flexural modulus. The method also includes generating a range of sound pressure vibrations by the plurality of sound panels respective of the flexural modulus of the panel and the single audio signal. 
     In yet another embodiment, a speakerless vehicle sound system includes an audio amplifier that includes a first channel configured to provide a first audio signal having a first frequency range and a second channel configured to provide a second audio signal having a second frequency range wherein the second frequency range is less than the first frequency range. The speakerless vehicle sound system also includes a first acoustic exciter communicatively coupled to the first channel and to a first vehicle sound panel formed of a material having a first flexural modulus. The first vehicle sound panel is configured to generate a first range of sound pressure vibrations dependent on the first flexural modulus, a first set of dimensions of the first vehicle sound panel, and the first audio signal. The speakerless vehicle sound system further includes a second acoustic exciter communicatively coupled to the second channel and to a second vehicle sound panel formed of a material having a second flexural modulus. The second flexural modulus is less than the first flexural modulus. The first vehicle sound panel is configured to generate a second range of sound pressure vibrations dependent on the second flexural modulus of material the second vehicle sound panel is formed of, a second set of dimensions of the second vehicle sound panel, and the second audio signal. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1-7  show example embodiments of the method and systems described herein. 
         FIG. 1  is schematic illustration of a vehicle audio system showing various speakers operably coupled to an amplifier and various exterior audio assemblies or acoustic exciters operably coupled to the amplifier. 
         FIG. 2  is a graph of an example frequency response of the vehicle audio system shown in  FIG. 1 . 
         FIG. 3  is a side elevation view of an acoustic panel assembly that may be used with the vehicle sound system shown in  FIG. 1 . 
         FIG. 4  is a side elevation view of an acoustic panel assembly that may be used with the vehicle sound system shown in  FIG. 1  in accordance with another example embodiment of the present disclosure. 
         FIG. 5  is a side perspective view of acoustic panel assembly during operation of acoustic exciter. 
         FIG. 6  is a perspective view of a vehicle, such as, but not limited to a side-by-side (S×S) off-road vehicle. 
         FIG. 7  is a flowchart of an example method of generating sound having a plurality of frequency responses. 
     
    
    
     Although specific features of various embodiments may be shown in some drawings and not in others, this is for convenience only. Any feature of any drawing may be referenced and/or claimed in combination with any feature of any other drawing. 
     Unless otherwise indicated, the drawings provided herein are meant to illustrate features of embodiments of the disclosure. These features are believed to be applicable in a wide variety of systems comprising one or more embodiments of the disclosure. As such, the drawings are not meant to include all conventional features known by those of ordinary skill in the art to be required for the practice of the embodiments disclosed herein. 
     DETAILED DESCRIPTION 
     Various embodiments of the present disclosure are better understood when read in conjunction with the appended drawings. To the extent that the figures illustrate diagrams of the functional blocks of various embodiments, the functional blocks are not necessarily indicative of the division between hardware circuitry. Thus, for example, one or more of the functional blocks (e.g., systems, devices, processors, controllers, or memories) may be implemented in a single piece of hardware (e.g., a general purpose signal processor or random access memory, hard disk, or the like) or multiple pieces of hardware. Similarly, any programs may be stand-alone programs, may be incorporated as subroutines in an operating system, may be functions in an installed software package, and the like. It should be understood that the various embodiments are not limited to the arrangements and instrumentality shown in the drawings. 
     As used herein, the terms “module”, “system,” or “unit,” may include a hardware and/or software system that operates to perform one or more functions. For example, a module, unit, or system may include a computer processor, controller, or other logic-based device that performs operations based on instructions stored on a tangible and non-transitory computer readable storage medium, such as a computer memory. Alternatively, a module, unit, or system may include a hard-wired device that performs operations based on hard-wired logic of the device. The modules, units, or systems shown in the attached figures may represent the hardware that operates based on software or hardwired instructions, the software that directs hardware to perform the operations, or a combination thereof. 
     As used herein, an element or step recited in the singular and proceeded with the word “a” or “an” should be understood as not excluding plural of the elements or steps, unless such exclusion is explicitly stated. Furthermore, references to “one embodiment” are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Moreover, unless explicitly stated to the contrary, embodiments “comprising” or “having” an element or a plurality of elements having a particular property may include additional such elements not having that property. 
     Various embodiments of methods and systems for controlling functions of a vehicle audio system are provided. It should be noted that although the various embodiments are described in connection with the automotive industry, such as, but not limited to, a truck, one or more embodiments may be implemented in different types of vehicles, in different industries and for different applications. Additionally, while embodiments described herein refer to a vehicle audio system that provides audio output external to the vehicle, such as in a truck bed of the vehicle, the audio output may be provided at other areas of the vehicle in other various embodiments. 
     One or more embodiments include a system, which may be implemented as a programmable logic controller (PLC), also referred to as a programmable logic circuit that controls various functions and operations of the audio system of the vehicle, such as the audio input, the audio output, equalization of the audio output, such as to control frequency response of the speakers, such as to control bass, treble and the like, battery saving features, such as to turn off various electrical systems, and the like. The controller may control display functions on one or more display devices or screens. 
     In various embodiments, the system may include both interior audio assemblies (e.g., speakers in a cabin of the vehicle) and exterior audio assemblies (e.g., acoustic exciters outside of the cabin of the vehicle to produce audio output external to the vehicle cabin). The exterior audio assemblies provide a full range of audio output external to the vehicle, such as for use when people are around the outside of the vehicle. For example, during tailgating, while doing chores, while washing the vehicle and the like, the vehicle audio system may be used and does not need to rely on speakers inside the vehicle cabin to produce the sound. As such, the windows or doors do not need to be open to listen to the audio system. 
     As used herein, flexural modulus or bending modulus is an intensive property of a material that is computed as the ratio of stress to strain in flexural deformation, or the tendency for the material to bend. The flexural modulus is inversely related to deflection—a lower deflection results in a higher flexural modulus. In other words, a higher flexural modulus material is “stiffer” than a lower flexural modulus material. 
     The following description refers to the accompanying drawings, in which, in the absence of a contrary representation, the same numbers in different drawings represent similar elements. 
       FIG. 1  is schematic illustration of a vehicle audio system  100  having speakers  102  operably coupled to an amplifier  104  and various exterior audio assemblies or acoustic exciters  106  operably coupled to amplifier  104 . Although vehicle audio system  100  is illustrated showing an interior audio system that includes speakers, vehicle audio system  100  may also be configured without the interior portion. An audio source device  108  provides a low power audio signal  109  to amplifier  104 . In various embodiments, audio source device  108  may be embodied in an FM, AM, or satellite radio receiver, a compact disk (CD) or MP3 player, and the like. In the illustrated embodiment, amplifier  104  is configured to amplify low power audio signal  109  and to output higher power audio signals  110  over one or more channels  111 . Each speaker  102  is communicatively coupled to a corresponding channel  111  of amplifier  104 . Similarly, each acoustic exciter  106  is communicatively coupled to a single channel  112  of amplifier  104 , which provides a single higher power audio signal  113 . In other embodiments, a second channel  115  may be used to power a portion of acoustic exciters  106 . 
     In the exemplary embodiment, amplifier  104  includes an interior audio module  114  with speakers  102  coupled to interior audio module  114  and an exterior audio module  116  with acoustic exciters  106  coupled to the exterior audio module  116 . Various selectable audio modes may operate interior audio module  114  and exterior audio module  116  in conjunction with each other, or one or the other of interior audio module  114  and exterior audio module  116  may be operated individually. 
     An equalizer  118  is only used with interior audio module  114  and speakers  102 . Equalizer  118  may operate speakers  102  at different frequencies. For example, each channel  111  may be operated at a different frequency. Equalizer  118  controls the output of the channels  111  differently from each other of channels  111 . Optionally, an output of amplifier  104  may be controlled by equalizer  118  to achieve a desired sound quality target including, but not limited to, factors such as distortion, clarity and frequency response for each of speakers  102 . Equalizer  118  may control the output of the channels  111  based on various factors, such as the characteristics of each speaker  102 , a mounting location of each speaker  102  within a vehicle. For reasons that are explained below, equalizer  118  is not needed or used with exterior audio module  116  and acoustic exciters  106 . Exterior audio module  116  provides an unequalized audio signal  113  to acoustic exciters  106 . 
       FIG. 2  is a graph  200  of an example frequency response of vehicle audio system  100  (shown in  FIG. 1 ). In the example embodiment, graph  200  includes an x-axis  202  graduated in units of frequency, such as, but not limited to, Hertz (Hz) and a y-axis  204  graduated in units of sound pressure level (SPL) or acoustic pressure graduated in units of for example, Pascal (Pa). A first trace  206  represents a relatively low frequency response, a second trace  208  represents a relatively high frequency response, and a third trace  210  represents a frequency response between low frequency response, first trace  206  and high frequency response, second trace  208 . SPL represents a local pressure deviation from the ambient atmospheric pressure, caused by a sound wave. 
     First trace  206  represents a bass frequency response between approximately 20 Hz and 8,000 Hz. Second trace  208  represents a treble frequency response between approximately 13,000 Hz and approximately 20,000 Hz, Third trace  210  represents a mid-range frequency response between approximately 6,000 Hz and 15,000 Hz, First trace  206 , second trace  208 , and third trace  210  together represent a full range of frequency responses, which a human typically can hear. Each of first trace  206 , second trace  208 , and third trace  210  are generated using a single audio signal channeled to identical acoustic exciters (shown in  FIG. 3 ) coupled to one or more sound panels (also shown in  FIG. 3 ) on a vehicle (shown in  FIG. 6 ). A vibratory response of each of the one or more sound panels is predetermined based on a flexural modulus of a material the sound panels are formed of, physical dimensions of the sound panels, dimensional features of the sound panels, stiffening or other flexural treatment of the sound panels, or combinations thereof. 
     The flexural modulus of the sound panels may be defined by the material properties of the material the sound panels are formed of. For example, a length of a fiber used in the material, the cross-section of the fibers, and a filler material used in forming the sound panel may define a certain flexural modulus of the sound panel. Likewise a density of the material and the mechanical joining of layers of the layer also facilitate defining the flexural modulus of the sound panel. 
     The flexural modulus of the sound panels may also be defined by physical dimensions of the sound panels. Such physical dimensions include a thickness of the sound panel, a gradient of the thickness across the sound panel, a length, a width, and an overall shape or outline of the sound panel can affect the structural modulus of the sound panel. 
     The flexural modulus of the sound panels may further be defined by dimensional features of the sound panels, stiffening, or other flexural treatment of the sound panels, including heat treatment and fastening configurations. 
       FIG. 3  is a side elevation view of an acoustic panel assembly  300  that may be used with vehicle audio system  100  (shown in  FIG. 1 ).  FIG. 4  is a side elevation view of an acoustic panel assembly  301  that may be used with vehicle audio system  100  (shown in  FIG. 1 ) in accordance with another example embodiment of the present disclosure. For example, acoustic panel assembly  300  can define an interior portion of a cargo bed of a vehicle and/or may define an interior portion of, for example, a cab or cabin of a vehicle. In the example embodiment, acoustic panel assembly  300  includes a sound panel  302  formed of a material having a respective flexural modulus. In various embodiments, the flexural modulus is homogeneous across a width  304 , height  306 , and a thickness  308  of sound panel  302 . In other embodiments, the flexural modulus is not homogeneous and may be varied throughout various areas  310  of sound panel  302  to tailor a vibratory response of sound panel  302  to acoustic exciters  106 . In  FIG. 3 , acoustic exciters  106  are shown in dotted lines because they are mounted to an opposite side  312  of sound panel  302 . Acoustic exciters  106  are coupled to sound panel  302  in areas predetermined to provide desired sound pressure vibrations. Each acoustic exciter  106  is configured to receive audio signal  113 . Audio signal  113  includes a full range of frequency responses including a bass frequency response, a treble frequency response, and a mid-range frequency response (as shown in  FIG. 2 ). Eeach of sound panels  302  is configured to generate an audible sound signal that includes a respective range of sound pressure vibrations dependent on the flexural modulus of material sound panels  302  are formed of, variations of dimensions of the sound panel, and audio signal  113  received by acoustic exciter  106  coupled to sound panels  302 . 
     Acoustic panel assembly  300  may be formed in a plurality of different shapes, such as, as illustrated, as a rectangular shape  314 , which may have portions  316  removed to form, in this example, a cutout for a wheel well having a height  318  and a width  320 . A plurality of fasteners  322  may be positioned in acoustic panel assembly  300  at predetermined locations to fix acoustic panel assembly  300  to a structure of the vehicle. Fasteners  322  may also provide an adjustable or selectable compressive force when fixing acoustic panel assembly  300  to the structure. Such variable compressive force may be used to tuning a frequency response of acoustic panel assembly  300 . 
       FIG. 5  is a side perspective view of acoustic panel assembly  300  during operation of acoustic exciter  106 . Acoustic panel assembly  300  includes acoustic exciter  106  coupled to sound panel  302 . In various embodiments, sound panel  302  may be formed as a structural component of the vehicle, a fairing component, and/or a decorative component of the vehicle. During operation, single higher power audio signal  113  is used to excite acoustic exciter  106 , which causes acoustic exciter  106  to vibrate at a predetermined rate under the influence of single higher power audio signal  113 . The vibrations are generated by acoustic exciter  106  in an axial direction with respect to cylinder axis  500 . The vibrations cause a deflection of sound panel  302 , which then causes variations  502 , for example, compressions and rarefactions in the sound pressure adjacent to sound panel  302 . Sound pressure variations  502  travel through the medium  504  of the air ambient to sound panel  302  and an ear  506  of a listener. In various embodiments, vehicle audio system  100  includes a plurality of acoustic panel assemblies  300 . Each acoustic exciter  106  associated with the plurality of acoustic panel assemblies  300  receives the same single higher power audio signal  113 . To generate high fidelity sound as perceived by ear  506  of the listener, single higher power audio signal  113  excites all acoustic exciters  106  similarly and it is the frequency response of sound panel  302  that splits the full frequency range single higher power audio signal  113  into bass, mid-range, and treble sound ranges based on the flexural modulus, dimensions, structure, etc. of sound panel  302 . In at least some known vehicle audio systems, an equalizer is used to separate various frequency ranges of an audio signal before separate different signals are directed to speakers. 
       FIG. 6  is a perspective view of a vehicle  600 , such as, but not limited to a side-by-side (S×S) off-road vehicle. In the example embodiment, vehicle  600  includes a passenger compartment  602  and a cargo bed  604 . Passenger compartment  602  includes doors  606 , passenger seats  608 , a dashboard,  610 , various vehicle controls  612 , and indications  614 . Doors  606  and dashboard  610  may include areas  616  where sound panel  302  can be positioned and used as part of vehicle audio system  100 . Cargo bed  604  may also have areas  618 , at which one or more sound panels  302  may also be positioned and used as part of vehicle audio system  100 . Selectable factors affecting the frequency response of sound panels  302  include the flexural modulus of the material the sound panel  302  is formed of, the size and shape of the sound panel  302 , surface features and structural additions to the sound panel  302 , heat treatment or other treatments of sound panel  302 . For example, bass and mid-range frequency responses are better suited for more remote placement of the associated acoustic exciter  106  because low frequency travels farther through media than do high frequencies. Additionally, bass response through objects, such as, walls, room dividers, and seat backs is better than high frequency response. Accordingly, placement of sound panels  302  tailored to low and mid-range applications is preferentially made to, for example, the sidewalls of cargo bed  604 , whereas placement of sound panels  302  tailored to high frequency applications is preferentially made to, for example, passenger compartment  602 . 
       FIG. 7  is a flowchart of an example method  700  of generating sound having a plurality of frequency responses. In the example embodiment, method  700  includes receiving  702 , by a plurality of acoustic exciters, a single audio signal including a plurality of frequency ranges including a low frequency range, a mid frequency range, and a high frequency range. The plurality of acoustic exciters are coupled to a corresponding plurality of sound panels. Each sound panel is formed of a material having a predetermined flexural modulus defined by at least one of a material composition of the sound panel, a set of physical dimensions of the sound panel, a mounting configuration of the sound panel, and a combination thereof. Method  1000  also includes generating  704  a range of sound pressure vibrations by the plurality of sound panels respective of the flexural modulus of the panel and the single audio signal. 
     This written description uses examples to describe the disclosure, including the best mode, and also to enable any person skilled in the art to practice the disclosure, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.