阅读说明：本技术 改善车辆中的驾驶员的收听体验的非对称的声学实现方式 (Asymmetric acoustic implementation to improve the listening experience of a driver in a vehicle ) 是由 R.温顿 C.路德维格 B.斯特林 A.亨斯根斯 于 2018-12-22 设计创作，主要内容包括：在至少一个实施方案中,提供一种音频系统。所述音频系统包含第一扩音器、第二扩音器和音频控制器。所述第一扩音器位于车辆的第一侧上,以向驾驶员传输第一音频信号。所述第二扩音器位于所述车辆的第二侧上,以向乘客传输第二音频信号。所述音频控制器被配置成通过以下操作中的至少一者来仅为所述车辆的所述驾驶员增加音频体验：控制提供给所述第一扩音器的电压以致使所述第一扩音器的第一总偏移大于所述第二扩音器的第二总偏移；以及限制仅输送给所述第一扩音器的电流量以防止所述第一扩音器由于过电流状况而临时关闭。(In at least one embodiment, an audio system is provided. The audio system includes a first microphone, a second microphone, and an audio controller. The first microphone is located on a first side of the vehicle to transmit a first audio signal to the driver. The second microphone is located on a second side of the vehicle to transmit a second audio signal to a passenger. The audio controller is configured to increase an audio experience only for the driver of the vehicle by at least one of: controlling a voltage provided to the first microphone to cause a first total offset of the first microphone to be greater than a second total offset of the second microphone; and limiting an amount of current delivered only to the first microphone to prevent the first microphone from temporarily shutting down due to an over-current condition.)

1. An audio system, the audio system comprising:

a first microphone located on a first side of a vehicle to transmit a first audio signal to a driver of the vehicle;

a second microphone located on a second side of the vehicle to transmit a second audio signal to an occupant of the vehicle; and

an audio controller configured to:

providing a first voltage to the first microphone consistent with a first total offset of the first microphone while transmitting the first audio signal to the driver; and

providing a second voltage to the second microphone consistent with a second total excursion of the second microphone while transmitting the second audio signal to the occupant,

wherein the first voltage is greater than the second voltage such that the first total offset of the first microphone is greater than the second total offset of the second microphone, thereby enabling the driver to experience an increased audio experience over that of the passenger.

2. The audio system of claim 1, wherein the audio controller is further configured to provide a third voltage to the first microphone such that the first microphone provides a predetermined frequency in the first audio signal, thereby enabling the driver to experience the predetermined frequency in the first audio signal.

3. The audio system of claim 2, wherein the audio controller is further configured to provide a fourth voltage to the second microphone to transmit the second audio signal to the passenger, the third voltage being greater than the fourth voltage to only enable the driver to listen to the first audio signal at the predetermined frequency.

4. The audio system of claim 1, where the audio controller is further configured to limit only the current of the first microphone to prevent the first microphone from overheating or temporarily turning off.

5. The audio system of claim 1, wherein the first microphone is located on a passenger side door of the vehicle to transmit the first audio signal to the driver.

6. The audio system of claim 5, wherein the second microphone is located on a driver-side door of the vehicle to transmit the second audio signal to the driver.

7. The audio system of claim 6, where the first and second loudspeakers are the same size and shape as one another.

8. The audio system of claim 7, wherein the first and second loudspeakers each transmit the first and second audio signals within the same frequency range as one another.

9. The audio system of claim 1, wherein the vehicle defines a centerline extending from a front of the vehicle to a rear of the vehicle to separate the first side of the vehicle from the second side of the vehicle.

10. The audio system of claim 9, wherein the first microphone is located at a first location on the first side of the vehicle and the second microphone is located at a second location on the second side of the vehicle such that the first microphone is located in the vehicle symmetrically to the second microphone in the vehicle.

11. An audio system, the audio system comprising:

a first microphone located on a first side of a vehicle to transmit a first audio signal to a driver of the vehicle;

a second microphone located on a second side of the vehicle to transmit a second audio signal to an occupant of the vehicle; and

an audio controller configured to limit the amount of current provided only to the first microphone to prevent the first microphone from temporarily turning off due to an over-current condition, thereby enabling the driver to experience an increased audio experience over that of the passenger.

12. The audio system of claim 11, wherein the audio controller is further configured to:

providing a first voltage to the first microphone consistent with a first total offset of the first microphone while transmitting the first audio signal to the driver; and

providing a second voltage to the second microphone consistent with a second total excursion of the second microphone while transmitting the second audio signal to the occupant.

13. The audio system of claim 12, where the first voltage is greater than the second voltage such that the first total offset of the first microphone is greater than the second total offset of the second microphone.

14. The audio system of claim 11, wherein the first microphone is located on a passenger side door of the vehicle to transmit the first audio signal to the driver.

15. The audio system of claim 14, wherein the second microphone is located on a driver-side door of the vehicle to transmit the second audio signal to the driver.

16. The audio system of claim 15, where the first and second loudspeakers are the same size and shape as one another.

17. The audio system of claim 16, where the first and second loudspeakers each transmit the first and second audio signals in the same frequency range as one another.

18. The audio system of claim 11, wherein the vehicle defines a centerline extending from a front of the vehicle to a rear of the vehicle to separate the first side of the vehicle from the second side of the vehicle.

19. The audio system of claim 18, wherein the first microphone is located at a first location on the first side of the vehicle and the second microphone is located at a second location on the second side of the vehicle such that the first microphone is located in the vehicle symmetrically to the second microphone in the vehicle.

20. An audio system, the audio system comprising:

a first microphone located on a first side of a vehicle to transmit a first audio signal to a driver of the vehicle;

a second microphone similar in size to the first microphone and located on a second side of the vehicle to transmit a second audio signal to an occupant of the vehicle; and

an audio controller configured to augment an audio experience only for the driver of the vehicle by at least one of:

controlling a voltage provided to the first loudspeaker such that a first total offset of the first loudspeaker is greater than a second total offset of the second loudspeaker, and

limiting an amount of current delivered only to the first microphone to prevent the first microphone from temporarily shutting down due to an over-current condition.

Technical Field

Aspects disclosed herein generally provide an asymmetric acoustic implementation for improving the listening experience of a driver in a vehicle.

Background

Various audio and speaker related manufacturers are well able to provide high performance audio related products for vehicles. However, these audio and speaker related manufacturers recognize that there are substantial growth opportunities in entry-level market audio systems. Furthermore, audio and speaker related manufacturers must not want to produce inferior audio sound systems to compromise their respective brands or reputations. Audio and speaker related manufacturers are looking for price competitive ways to provide desirable sound effects.

Disclosure of Invention

In at least one embodiment, an audio system is provided. The audio system includes a first microphone, a second microphone, and an audio controller. The first microphone is located on a first side of the vehicle to transmit a first audio signal to the driver. The second microphone is located on a second side of the vehicle to transmit a second audio signal to a passenger. The audio controller is configured to increase an audio experience only for the driver of the vehicle by at least one of: controlling a voltage provided to the first loudspeaker to cause a first total offset (extension) of the first loudspeaker to be greater than a second total offset of the second loudspeaker; and limiting an amount of current delivered only to the first microphone to prevent the first microphone from temporarily shutting down due to an over-current condition.

In at least another embodiment, an audio system is provided. The audio system includes a first microphone, a second microphone, and an audio controller. The first microphone may be located on a first side of a vehicle to transmit a first audio signal to a driver of the vehicle. The second microphone may be located on a second side of the vehicle to transmit a second audio signal to an occupant of the vehicle. The audio controller is configured to: providing a first voltage to the first microphone consistent with a first total offset of the first microphone while transmitting the first audio signal to the driver; and providing a second voltage to the second microphone consistent with a second total excursion of the second microphone while transmitting the second audio signal to the occupant. The first voltage is greater than the second voltage such that the first total excursion of the first loudspeaker is greater than the second total excursion of the second loudspeaker, thereby enabling the driver to experience an increased audio experience over that of the passenger.

In at least one embodiment, an audio system is provided. The audio system includes a first microphone, a second microphone, and an audio controller. The first microphone may be located on a first side of a vehicle to transmit a first audio signal to a driver of the vehicle. The second microphone may be located on a second side of the vehicle to transmit a second audio signal to an occupant of the vehicle. The audio controller is configured to limit the amount of current provided only to the first microphone to prevent the first microphone from temporarily turning off due to an over-current condition, thereby enabling the driver to experience an increased audio experience over that of a passenger.

Drawings

Embodiments of the present disclosure are particularly pointed out in the appended claims. However, other features of the various embodiments will become more apparent and will be best understood by referring to the following detailed description in conjunction with the accompanying drawings, in which:

FIG. 1 generally depicts a vehicle audio system according to one embodiment;

FIG. 2 generally depicts a method for controlling an asymmetric loudspeaker in a vehicle according to one embodiment;

FIG. 3 generally depicts a graph corresponding to a peak current magnitude frequency response of an asymmetric loudspeaker that causes excessive current to be drawn from an amplifier;

FIG. 4 generally depicts a graph corresponding to a peak current magnitude frequency response of an asymmetric loudspeaker that mitigates drawing excessive current from an amplifier, according to one embodiment; and

fig. 5 generally depicts a graph corresponding to an increased excursion of an asymmetric loudspeaker, according to one embodiment.

Detailed Description

As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.

It is recognized that any of the circuits or other electrical devices disclosed herein may include any number of microcontrollers, Graphics Processor Units (GPUs), integrated circuits, memory devices (e.g., F L ASH, Random Access Memory (RAM), Read Only Memory (ROM), Electrically Programmable Read Only Memory (EPROM), Electrically Erasable Programmable Read Only Memory (EEPROM), or other suitable variations thereof) and software that cooperate with one another to perform the operations disclosed herein.

Aspects disclosed herein generally provide an asymmetric acoustic implementation for improving the listening experience of a driver in a vehicle. The asymmetric acoustic implementation may provide an economic upgrade for vehicles equipped with entry level based audio. For example, rather than using an acoustically matched pair of loudspeakers, one loudspeaker of a corresponding pair may include an upgraded acoustic performance capability (e.g., an asymmetric loudspeaker) relative to the other loudspeaker of the pair. This implementation produces an acoustically asymmetric experience. Additionally, an asymmetric loudspeaker approach may be incorporated in the front row of the vehicle, and a corresponding loudspeaker with enhanced acoustic output capability (e.g., an asymmetric loudspeaker) may be oriented in the vehicle to transmit audio therefrom to enable the driver of the vehicle to enjoy enhanced audio playback resulting from the increased audio capability attributed to the asymmetric loudspeaker.

Fig. 1 generally depicts an audio system 10 in a listening environment 12 of a vehicle 14 according to one embodiment. The listening environment 12 includes a plurality of seats 16 (e.g., a first seat 16a, a second seat 16b, a third seat 16c, and a fourth seat 16d) located in a row 18 (e.g., a first row 18a and a second row 18b) of the vehicle 14. It is recognized that the number of seats 16 and rows 18 in the vehicle 14 may vary based on the particular implementation of the vehicle 14. The first seat 16a is substantially adjacent to the second seat 16 b. The first seat 16a may be a driver seat and the second seat 16b may be a front passenger seat. The third seat 16c may be a left rear passenger seat and the fourth seat 16d may be a right rear passenger seat. As illustrated, the first seat 16a and the second seat 16b may be substantially aligned in the first row 18 a. The second row 18b is generally located rearward of the first row 18a in the vehicle 14.

The vehicle 14 includes a plurality of loudspeakers 20 (e.g., a first loudspeaker 20a, a second loudspeaker 20b, a third loudspeaker 20c, and a fourth loudspeaker 20d) located within the listening environment 12. The first microphone 20a may be proximate the first seat 16a and distal the second seat 16 b. The second microphone 20b may be proximate the second seat 16b and distal the first seat 16 a. The first microphone 20a may be located in a left hand door (not shown) or within a headrest (not shown) of the first seat 16 a. The second microphone 20b may be located in a right hand door (not shown) or within a headrest (not shown) of the second seat 16 b. A first lateral axis 22 extending from the left side of the vehicle 14 to the right side of the vehicle 14 may intersect the first loudspeaker 20a and the second loudspeaker 20 b. The first lateral axis 22 may extend perpendicular to a centerline 24 of the vehicle 14.

Additionally or alternatively, the first and second microphones 20a and 20b may be aligned on a first plane (not shown). The first plane may extend perpendicular to a center plane of the vehicle 14. The centerline 24 may be positioned on the center plane. Additionally or alternatively, the first loudspeaker 20a may be positioned at a location that is a mirror image of the second loudspeaker 20 b. The centerline 24 (and/or a center plane) may extend from the front of the vehicle 14 to the rear of the vehicle 14 and serve as a mirror line and/or a mirror plane for the first and second microphones 20a and 20b, respectively. The orientation of the first loudspeaker 20a in the vehicle 14 may thus be a mirror image orientation of the second loudspeaker 20 b. In general, the first and second loudspeakers 20a and 20b may each be located on similar three-dimensional coordinate axes on each of the first and second gates, respectively, providing the mirror image orientation. Likewise, the third loudspeaker 20c and the fourth loudspeaker 20d may each be located on a similar three-dimensional coordinate axis on each of the third gate and the fourth gate, respectively, providing the mirror image orientation.

An audio controller 26 is operatively coupled to the microphone 20. The audio controller 26 transmits an audio signal to the microphone 20. The microphone 20 plays back audio data in the listening environment 12 in response to the audio signal. The audio controller 26 generally processes information used in connection with: AM radio, FM radio, satellite radio, navigation system, user interface, display, wireless communication with a mobile device via bluetooth, WiFi, or other wireless protocols, and the like. An audio amplifier 27 is operatively coupled to the audio controller 26. Audio amplifier 27 may be integrated with audio controller 26. In another embodiment, audio amplifier 27 may be located external to audio controller 26. Audio amplifier 27 is generally configured to receive audio output from audio controller 26 and amplify the amplitude of the audio output to a level sufficient to drive the various loudspeakers 20. It is recognized that the audio controller 26 may generally include any number of hardware-based processors and memories. The audio controller 26 may use various hardware-based processors to execute any number of software algorithms stored on memory to provide surround sound, audio tuning such as for gain, EQ, or any number of various audio adjustments, to enhance the listening experience within the listening environment. The audio controller 26 may include any number of channels, with each corresponding channel coupled to a respective loudspeaker 20 via an audio amplifier 27 for transmitting audio signals to the respective loudspeaker 20.

The second microphone 20b located in the front passenger door (or second door) may be configured with enhanced acoustic output capability (or increased acoustic output capability) as compared to the first microphone 20a located in one or more driver doors in the vehicle 14. The second loudspeaker 20b is typically located at a predetermined distance from the driver and enables the driver to optimally hear any corresponding audio processing effect since the distance is a particular distance away from the second loudspeaker 20 b. In addition, the second microphone 20b is located in the door to provide the driver with the best audio directivity. The audio transmitted by the first microphone 20a may be too close to the driver and is typically disposed or located in the door to provide optimal audio directivity to the passenger in the second seat 12 b. It may be advantageous to increase the listening experience for the driver in the vehicle 14 using the second microphone 20b, which includes increased audio output capability, while taking advantage of the reduced acoustic output capability associated with the first microphone 20a (and the third and fourth microphones 20c and 20d) that generally provide audio output to the passenger (i.e., non-driver), thereby reducing the overall cost of the audio system. Some audio systems generally provide a symmetric implementation that provides similar audio capabilities of the first and second microphones 20a and 20b (or all of the microphones 20 located in corresponding doors of the vehicle 14). In this case, the acoustic experiences of the driver and the passenger are similar to each other. However, the disclosed audio system 10 incorporates an asymmetric implementation in which the second loudspeaker 20b (or asymmetric loudspeaker 20b) provides an increased acoustic output capability compared to the acoustic output capability of the first loudspeaker 20 a.

For example, the audio controller 26 may execute a voltage manager routine to drive the asymmetric microphone 20b at a higher voltage for a predetermined frequency than the remaining microphones 20a, 20b, and 20c in the vehicle 14. In this case, the driver may experience the predetermined frequency in the audio output from the asymmetric loudspeaker 20 b. In addition, audio controller 26 may drive asymmetric loudspeaker 20b at a corresponding voltage consistent with the total excursion capacity of asymmetric loudspeaker 20b over its frequency range to increase the excursion capability of asymmetric loudspeaker 20 b. The offset is generally defined as the total length of the cone of the asymmetric loudspeaker 20b that travels linearly from its original rest position in response to the voltage.

The audio controller 26 may also execute a power manager routine to limit the amount of current supplied to the asymmetric microphone 20b to prevent overheating of the asymmetric microphone 20 b. For example, the audio controller 26 may store information corresponding to the total impedance of the asymmetric microphone 20b and control the amount of current provided to the asymmetric microphone 20b to prevent overheating. Information relating to the total impedance of the asymmetric microphone 20b may be stored in the audio controller 26 prior to or during installation of the audio controller 26 and/or the microphone 20 in the vehicle 14. It is recognized that the asymmetric loudspeaker 20b may be implemented as a midrange and a subwoofer. The above-described features correspond to the increased acoustic capabilities provided by the audio controller 26 and the asymmetric loudspeaker 20 b. Various examples of ways to achieve increased excursion of the speaker and prevention of overheating of the speaker (i.e., current control) are set forth in U.S. patent No.8,194,869 to michelich et al, which is incorporated herein by reference in its entirety.

In a symmetric implementation, the left loudspeaker is selected to mirror the right loudspeaker such that the acoustic effects of the left and right loudspeakers match (e.g., same frequency range, same efficiency, same material composition, etc.). In addition, the left and right loudspeakers are identical in size due to the mirror image. This allows the left and right loudspeakers to be common parts, so that the left loudspeaker can be replaced with the right loudspeaker (and vice versa). In terms of hardware arrangement, the left loudspeaker is acoustically symmetric to the right loudspeaker. Also, in a symmetric implementation, the driver may have the same acoustic experience as the passenger in the vehicle. This is due to the symmetrical arrangement of the loudspeakers and their symmetrical sound effect.

However, with the asymmetric implementation set forth herein, an asymmetric sound effect between the asymmetric loudspeaker 20b and the first loudspeaker 20a, the driver may experience an acoustic experience that is distinct from the rest of the passengers in the vehicle 14. The asymmetric microphone 20b may provide a better acoustic experience for the driver in the vehicle 14 than experienced by the vehicle occupants in the vehicle 14, as compared to the first, third, and fourth microphones 20a, 20c, and 20 d. In general, in a vehicle where one seat is occupied more frequently than another seat in the same row (such as a driver seat relative to an adjacent passenger seat), an asymmetric arrangement may be desirable because this arrangement (e.g., asymmetric microphone 20b) includes increased acoustic output capability.

While the asymmetric microphone 20b may include an increased acoustic capability over that of the first, third and fourth microphones 20a, 20c, 20d, it is recognized that the asymmetric microphone 20b may have similar dimensional properties to those of the first, third and/or fourth microphones 20a, 20c, 20 d. For example, the asymmetric microphone 20b may be substantially dimensionally identical to the first microphone 20a, particularly in terms of packaging, mounting, and assembly angles (i.e., mounting the speaker 20 into various cavities of a vehicle door). This approach does not require the vehicle metal panel to have different cavity sizes to receive the various speakers 20, which reduces the complexity of the Original Equipment Manufacturer (OEM). Additionally, this method provides a mirror image packaging method of metal plates on each side of the centerline 24 of the vehicle 14. Furthermore, the mirror image packaging approach of the microphone 20 in the vehicle 14 enables the use of a universal mounting bracket that is applicable to the asymmetric microphone 20b and the first microphone 20 a. When the size of the asymmetric loudspeaker 20b is significantly different from the size of the second loudspeaker 20b, such differences increase the overall manufacturing and complexity of the OEM, which may increase cost.

In one example, the asymmetric loudspeaker 20b may have a cone diameter of 6 inches, and the first loudspeaker 20a may also have a cone diameter of 6 inches. In addition, the asymmetric microphone 20b may have a predetermined depth. In one example, the total depth of the first loudspeaker 20a may be the same as the depth of the asymmetric loudspeaker 20 b. In another example, the total depth of the asymmetric loudspeaker 20b may be different from the total depth of the asymmetric loudspeaker 20 b.

Fig. 2 generally depicts a method 50 for controlling an asymmetric loudspeaker 20b in a vehicle 14 to provide increased acoustic output capability, according to one embodiment.

In operation 52, the audio controller 26 drives the asymmetric loudspeaker 20b at a high voltage compared to the remaining loudspeakers 20a, 20c and 20 d. In this case, the asymmetric loudspeaker 20b may provide a fuller or richer gain of the audio signal at various frequencies based on the higher voltage.

In operation 54, the audio controller 26 may drive the asymmetric loudspeaker 20b at a corresponding voltage consistent with the total excursion capacity of the asymmetric loudspeaker 20b over its frequency range to increase the excursion capability of the asymmetric loudspeaker 20 b. By maximizing the amount of offset provided by the asymmetric loudspeaker 20b, the asymmetric loudspeaker 20b may provide deeper bass for low frequency audio and may avoid blurred or swollen low frequency output. In general, the asymmetric loudspeaker 20b may be arranged to provide a larger offset than the offset of the remaining loudspeakers 20a, 20c and 20 d. In one example, the remaining loudspeakers 20a, 20c and 20d may not be arranged to provide a level of excursion compared to that provided by the asymmetric loudspeaker 20b due to their configuration (or mechanical properties). For example, assuming that the asymmetric loudspeaker 20b may have mechanical properties that enable an increased level of excursion, the audio controller 20b drives the asymmetric loudspeaker 20b at a corresponding voltage consistent with the total excursion capacity of the asymmetric loudspeaker 20b to achieve the desired excursion. Thus, the audio controller 26 may drive the asymmetric loudspeaker 20b at a different voltage when compared to the voltages used to drive the remaining loudspeakers 20a, 20c and 20 d.

In operation 56, the audio controller 26 limits the amount of power delivered to the asymmetric loudspeaker 20b to prevent overheating of the voice coil of the asymmetric loudspeaker 20 b. Excessive current may damage the asymmetric microphone 20b or temporarily turn off the asymmetric microphone 20 b. The audio controller 26 may not necessarily limit the amount of power delivered to the remaining loudspeakers 20a, 20c and 20d, as these loudspeakers 20a, 20c and 20d may have different mechanical properties (or lesser mechanical properties or other performance properties) than the mechanical properties of the asymmetric loudspeaker 20 b.

Fig. 3 generally depicts a graph 70 corresponding to the peak current magnitude frequency response of the microphone 20 that causes excessive current to be drawn from the amplifier 27. The graph 70 generally depicts the manner in which an over-current exists and the manner in which the asymmetric loudspeaker 20b is affected when the audio controller 26 does not execute a power manager routine to limit the amount of power provided to the asymmetric loudspeaker 20 b. Waveform 72 generally corresponds to a peak current magnitude with respect to frequency response for the first microphone 20 a. Waveform 74 generally corresponds to a peak current magnitude with respect to frequency response for an asymmetric loudspeaker 20 b. Waveform 76 generally corresponds to the peak current limit. As shown in fig. 3, the peak current magnitude with respect to frequency response for the asymmetric loudspeaker 20b exceeds the peak current limit 76 at multiple frequencies. The excess in peak current magnitude for the asymmetric loudspeaker 20b is generally attributed to the lower or reduced impedance level associated with the asymmetric loudspeaker 20 b.

Thus, this condition may alleviate the condition where the peak current of the asymmetric loudspeaker 20b exceeds the peak current limit 74 when the audio controller 26 executes a power manager routine to limit the amount of power provided to the asymmetric loudspeaker 20 b. This condition is illustrated in the graph 70 of fig. 4. Fig. 4 also illustrates waveforms 72, 74, and 76. As the audio controller 26 executes the power manager routine, the waveform 74 illustrates that the peak current magnitude within the frequency range (see waveform 74) does not exceed the peak current limit 76.

In general, it is possible to reduce the total impedance of the asymmetric loudspeaker 20b to take advantage of the low peak voltage (e.g., nominal 14V peak) available for the asymmetric loudspeaker 20 b. A problem with reducing the impedance is that over some frequency ranges, the reduced impedance may result in excessive current being drawn from amplifier 27. Excessive current draw may damage amplifier 27 or at least result in temporary shutdown of amplifier 27, which is unacceptable.

The audio controller 26 may also execute a power manager routine to limit the amount of current supplied to the asymmetric microphone 20b to prevent overheating of the asymmetric microphone 20 b. For example, the audio controller 26 may store information corresponding to the total impedance of the asymmetric microphone 20b and control the amount of current provided to the asymmetric microphone 20b to prevent overheating. Information relating to the total impedance of the asymmetric microphone 20b may be stored in the audio controller 26 prior to or during installation of the audio controller 26 and/or the microphone 20 in the vehicle 14. Thus, when it is expected that the total impedance of the asymmetric loudspeaker 20b may be low, the audio controller 26 may limit the amount of current provided to the asymmetric loudspeaker 20b via the audio amplifier 27 to avoid exceeding the peak current limit 76. As shown in fig. 4, the total peak current of the asymmetric loudspeaker 20b is less than the total peak current of the first loudspeaker 20 a. This condition prevents the asymmetrical microphone 20b from overheating.

Fig. 5 generally depicts a graph 80 corresponding to an increased excursion of the asymmetric loudspeaker 20b in accordance with one embodiment, the waveform 82 generally depicts a sound pressure level (SP L) within a frequency range for the first loudspeaker 20a, the waveform 84 generally depicts an SP L within the frequency range for the asymmetric loudspeaker 20b as shown, the waveform 84 exhibits an increase in SP L within the frequency range below (i.e., for the asymmetric loudspeaker 20b) compared to SP L within the frequency range for the first loudspeaker 20a due to a higher efficiency of the excursion present on the asymmetric loudspeaker 20b as compared to the total excursion of the first loudspeaker 20 a.

While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. In addition, features of various implementing embodiments may be combined to form further embodiments of the invention.