Automobile audio system

• US 20040091123A1
• Filed: 11/08/2002
• Published: 05/13/2004
• Est. Priority Date: 11/08/2002
• Status: Active Grant

• Current Assignee: Bose Corporation
• Original Assignee: Bose Corporation
• Inventors: Holmi, Douglas J., Greenberger, Hal P., Miyazaki, Hiroshi, Ludwig, Christopher, Stark, Michael W., Kawakami, Seiji, Givens, William L., Westley, Brandon B.
• Granted Patent: US 7,483,539 B2
• Time in Patent Office: Days
• US Class Current: 381/86
• CPC Class Codes: H04B 1/082 to be used in vehicles H04B1/086 takes precedence; holding or mounting accessories B60R11/02
• CPC Class Codes: H04R 2499/13 Acoustic transducers and sound field adaptation in vehicles
• CPC Class Codes: H04S 7/30 Control circuits for electronic adaptation of the sound field
• CPC Class Codes: H04S 7/307 Frequency adjustment, e.g. tone control H04S7/301 takes precedence
• CPC Class Codes: H04S 7/40 Visual indication of stereophonic sound image

Abstract

The invention features a dual-mode audio system for an automobile which in one mode is configured for play while the doors to the automobile are closed, and in a second mode, is configured for play while a door, such as a tailgate, is opened. Additionally, the invention also features a battery monitor which monitors the operating condition of the battery and may estimate the energy capacity of the battery. The system may also take power conservation measures if the system determines that the engine is not running or the operating condition of the batter reaches a predetermined state. The invention also features a remote control integrated within a key fob for controlling the audio system. The invention features various orientations for mounting a pair of loudspeakers within an automobile which directly radiate sound out of a rear opening of the automobile.

Claims

1. A method for operating an audio system in an automobile having a plurality of doors, the audio system including at an audio source that produces a plurality of audio signals, the method comprising the steps of:

implementing a first system configuration;

receiving input indicating a change in operating mode; and

in response to input indicating a change in operating mode, implementing a second system configuration which is different from the first system configuration, wherein the second system configuration is implemented when one of the doors of the automobile is open.

2. The method of claim 1, wherein one of the doors of the automobile is a tailgate and wherein implementing a second system configuration occurs when the tailgate is opened.

3. The method of claim 2, wherein performing the second system configuration occurs when the tailgate is closed.

4. The method of claim 1, further comprising the steps of:

receiving an input indicating that the automobile'"'"'s engine is not running; and

in response to the input indicating that the automobile'"'"'s engine is not running, adjusting the first or second system configuration in order to reduce power consumption of the system.

5. The method of claim 1, wherein the audio system further includes a plurality of loudspeakers and the step of implementing a first system configuration comprises implementing a first system topology;

and the step of implementing a second system configuration comprises implementing a second system topology which is different from the first system topology.

6. The method of claim 1, wherein the audio system further includes a plurality of loudspeakers, and the step of implementing a second system configuration comprises turning off one or more of the plurality of speakers.

7. The method of claim 6, wherein the audio system includes an amplifier which provides an audio signal to one or more loudspeakers, and the step of turning off one or more of the loudspeakers comprises one of the following steps:

muting the output of the amplifier,

placing the amplifier in standby mode,

reducing the voltage of the audio signal input to the amplifier to approximately zero,

disconnecting the one or more loudspeakers from the amplifier, or

removing electrical power from the amplifier.

8. The method of claim 1, wherein the step of implementing a first system configuration comprises performing a first set of signal processing operations on the plurality of audio signals and the step of implementing a second system configuration comprises performing a second set of signal processing operations on the plurality of audio signals, wherein the first set of signal processing operations are different from the second set of signal processing operations.

9. The method of claim 5, wherein the audio source generates at least a left channel of audio data, a right channel of audio data, a left surround channel of audio data, and a right surround channel of audio data, and the audio system further includes at least a pair of front speakers located near the front of the passenger compartment in the automobile and a pair of rear speakers located near the rear of the passenger compartment in the automobile, and wherein the first system topology comprises:

providing the left and right channels of audio data to the front pair of speakers; and

providing the left and right surround channels of audio data to the rear pair of speakers;

and wherein the second system topology comprises;

providing the left and right channels of audio data to the rear pair of speakers.

10. The method of claim 9 wherein the second system topology further comprises providing the left and right surround channels of audio data to the front pair of speakers.

11. The method of claim 1 wherein the step of implementing the first system configuration comprises:

performing a set of equalization processes having a first frequency response on the plurality of audio signals; and

wherein the step of implementing the second system configuration comprises;

performing a set of equalization processes having a second frequency response on the plurality of audio signals.

12. The method of claim 11 wherein performing a set of equalization processes having a first frequency response comprises:

sending one or more of the plurality of audio signals through a high pass filter having a first cutoff frequency; and

wherein performing a set of equalization processes having a second frequency response comprises;

sending one or more of the plurality of audio signals through a high pass filter having a second cutoff frequency.

13. The method of claim 4 wherein the step of adjusting the first or second system configuration to reduce power consumption comprises changing one or more signal processing operations in the first or second system configuration.

14. The method of claim 13, wherein the each of the plurality of audio signals are associated with a signal path, and the step of changing one or more signal processing operations in the first or second system configuration comprises reducing the gain in one or more of the signal paths.

15. The method of claim 13, wherein the step of changing one or more signal processing operations in the first or second system configuration comprises controlling the maximum output power level of the audio system.

16. The method of claim 15, wherein the audio system includes a plurality of variable gain elements and the step of controlling the maximum output power level comprises:

receiving one or more audio signals from the audio source;

detecting the level of one or more audio signals; and

dynamically adjusting the gain of one or more variable gain elements as a function of the detected level of the one or more audio signals.

17. The method of claim 4 wherein the system further includes a plurality of loudspeakers and the step of adjusting the first or second system configuration to reduce power consumption comprises turning off one or more of the loudspeakers in the first or second system configuration.

18. The method of claim 17 wherein the audio system includes an amplifier which provides an audio signal to one or more loudspeakers, and the step of turning off one or more of the loudspeakers comprise one of:

muting the output of the amplifier

placing the amplifier in standby mode,

reducing the voltage of the audio signal input into the amplifier to approximately zero,

disconnecting the one or more loudspeakers from the amplifier, or

removing electrical power from the amplifier.

19. The method of claim 8, wherein the audio system further includes a plurality of variable gain elements and the step of performing first sets of signal processes comprises:

receiving one or more audio signals from the audio source;

detecting the level of one or more audio signals; and

dynamically adjusting the gain of one or more variable gain elements as a function of the level of the one or more audio signals;

and wherein the step of performing the second set of signal processes comprises;

receiving one or more audio signals from the audio source;

detecting the level of one or more audio signals; and

dynamically adjusting the gain of one or more variable gain elements as a function of the level of the one or more audio signals, where the function used in the second set of signal processes is different from the function used in the first set of signal processes.

20. The method of claim 8, wherein each of the plurality of audio signals have an associated signal path and the step of performing first and second sets of signal processes comprises:

receiving one or more audio signals from the audio source; and

adjusting the gain of one or more signal paths; and

wherein the step of performing the second set of signal processes comprises;

receiving one or more audio signals from the audio source; and

adjusting the gain of one or more signal paths, wherein the gain of one or more signal paths in the second set of signal processes is different from the gain of the same one or more signal paths in the first set of signal processes.

21. The method of claim 8 wherein the audio system further includes a plurality of equalization processes, and the step of performing a second set of signal processing operations comprises:

receiving one or more audio signals from the audio source; and

adjusting the frequency response of the equalization process performed on one or more of the audio signals received from the audio source.

22. The method of claim 8, wherein the audio system further includes a plurality of loudspeakers and the step of performing a second set of signal processing operations comprises:

receiving a plurality of audio signals from an audio source;

performing spatial enhancement signal processing on a group of the audio signals; and

transmitting one or more spatially enhanced audio signals to a first set of the plurality of the loudspeakers.

23. The method of claim 8, wherein the step of performing a first set of signal processing operations comprises:

receiving one or more audio signals from the audio source;

performing first spatial enhancement signal processing on one or more sets of the received audio signals; and

wherein the step of performing a second set of signal processing operations comprises;

performing second spatial enhancement signal processing on one or more sets of received audio signals, wherein first and second spatial enhancement signal processing operations are different.

24. The method of claim 1, wherein the step of receiving input indicating a change in operating mode comprises:

monitoring one or more physical conditions of the automobile; and

generating a switch command based on a change in one or more of the monitored physical conditions.

25. The method of claim 24, wherein one or more of the monitored physical conditions includes one of the following:

whether a door is open, whether the automobile'"'"'s engine is running, or whether an occupant is present within the automobile passenger compartment.

26. The method of claim 1, wherein the step of receiving input indicating a change in operating mode comprises:

providing a switch accessible to a user, the switch having at least two states; and

receiving an input based on the state of the switch.

27. The method of claim 26, wherein the switch is located near the rear of the automobile within the passenger compartment.

28. The method of claim 26, wherein the switch is located on a remote control device.

29. The method of claim 28, wherein the remote control device is a key fob.

30. The method of claim 1, further comprising the steps of:

monitoring one or more operating conditions of the battery; and

causing the audio system to take an action based on one or more of the monitored operating conditions of the battery.

31. The method of claim 30, wherein the step of causing the audio system to take an action based on the monitored operating conditions of the battery comprises:

comparing one or more of the monitored operating conditions of the battery to a predetermined state; and

if one or more of the monitored operating conditions reaches the predetermined state, then triggering an alarm.

32. The method of claim 31, wherein the alarm is an audible alarm, visual alarm, or tactile alarm.

33. The method of claim 30, wherein the step of causing the audio system to take an action based on one or more of the monitored operation conditions of the battery comprises:

comparing one or more of the monitored operating conditions of the battery to a predetermined state; and

if one or more of the monitored operating conditions reaches the predetermined state, then reducing the power consumption of the audio system.

34. The method of claim 33 wherein the audio system further includes a plurality of equalization processes, and the step of reducing the power consumption of the audio system comprises:

receiving one or more audio signals from an audio source; and

adjusting one or more equalization process applied to one or more audio signals to change the frequency response of the audio system.

35. The method of claim 34, wherein one of the plurality of equalization processes includes a high pass filter having a cutoff frequency, and the step of adjusting one or more equalization processes comprises raising the cutoff frequency of the high pass filter.

36. The method of claim 34, wherein one of the plurality of equalization processes includes a high pass filter, and the step of adjusting the equalization processes comprises adjusting the order of the high pass filter.

37. The method of claim 33, wherein each of the plurality of audio signals have an associated signal path, and the step of reducing the power consumption of the audio system comprises reducing the gain in one or more of the audio signal paths.

38. The method of claim 33, wherein the audio system further includes a plurality of variable gain elements and the step of reducing the power consumption of the audio system comprises:

receiving one or more audio signals from the audio source;

detecting the level of one or more of the audio signals, and

dynamically adjusting the gain of one or more variable gain elements as a function of the detected level of the one or more audio signals.

39. The method of claim 33 wherein the system further includes a plurality of loudspeakers and the step of reducing the power consumption of the audio system comprises turning off one or more of the loudspeakers.

40. The method of claim 39 wherein the audio system includes an amplifier which provides an audio signal to one or more loudspeakers, and the step of turning off one or more of the loudspeakers comprises one of the following steps:

muting the output of the amplifier,

placing the amplifier in standby mode,

reducing the voltage of the audio signal input into the amplifier to approximately zero,

disconnecting the one or more loudspeakers from the amplifier, or

removing electrical power from the amplifier.

41. The method of claim 30, wherein the step of causing the audio system to take an action based on the monitored operating conditions of the battery comprises:

comparing one or more monitored operating conditions of the battery to a predetermined state; and

if the monitored operating conditions reaches the predetermined state, then shutting off the audio system.

42. The method of claim 30, wherein the step of taking an action based on the one or more monitored operating conditions of the battery comprises:

comparing one or more of the monitored conditions of the battery to a predetermined state; and

if the monitored condition of the battery reaches the predetermined state, then causing the automobile to start its engine.

43. The method of claim 30, further comprising:

estimating the remaining capacity of the battery based on one or more of the monitored operating conditions of the battery.

44. The method of claim 43, wherein the step of causing the audio system to take an action based on the monitored battery condition comprises:

comparing the estimated remaining capacity of the battery to a predetermined value; and

if the estimated battery capacity is equal to or less than the predetermined value, then triggering an alarm.

45. The method of claim 44, wherein the alarm is an audible alarm, visual alarm, or tactile alarm.

46. The method of claim 43, wherein the step of causing the audio system to take an action based on the monitored battery condition comprises:

comparing the estimated capacity of the battery to a predetermined value; and

if the estimated battery capacity is equal to or less than the predetermined value, then reducing the power consumption of the audio system.

47. A method for remote control of an audio system in an automobile, comprising:

providing a key fob having a plurality of buttons;

defining a first set of commands corresponding to each button for the plurality of buttons, wherein first set of commands includes a command causing the automobile to actuate its door locks;

defining a second set of commands corresponding to one or more of the plurality of buttons, wherein the second set of commands includes one or more commands for controlling the audio system of the automobile; and

switching between the first set of commands and the second set of commands based on a predetermined condition.

48. The method of claim 47, wherein the key fob further includes a switch having two states, and the predetermined condition is a state of the switch.

49. The method of claim 47, wherein the audio system comprises a first mode of operation and a second mode of operation and wherein the predetermined condition is the state of the mode of operation of the audio system, such that the first set of commands are valid when the audio system is in the first mode of operation and the second set of commands are valid when the audio system is in the second mode of operation.

50. A method for operating an audio system in a vehicle with a battery, the method comprising:

monitoring one or more operating conditions of the battery;

comparing one or more of the monitored conditions of the battery to a predetermined state; and

if one or more of the monitored operating conditions of the battery reaches the predetermined state, then triggering an alarm.

51. The method of claim 50 wherein the alarm comprises a audible alarm, visual alarm, or tactile alarm.

52. The method of claim 50, wherein monitoring one or more operating conditions of the battery comprises one or more of following:

sensing the output voltage level of the battery,

sensing the discharge current of the battery;

or

sensing the ambient temperature.

53. A method for operating an audio system in a vehicle with a battery, the method comprising:

monitoring one or more operating conditions of the battery; and

comparing one or more of the monitored conditions of the battery to a predetermined state; and

if one or more of the monitored operating conditions of the battery reaches the predetermined state, then causing the automobile to start its engine.

54. The method of claim 53, wherein monitoring one or more operating conditions of the battery comprises one or more of following:

sensing the output voltage level of the battery,

sensing the discharge current of the battery;

or

sensing the ambient temperature.

55. A method for operating an audio system having a plurality of speakers in a vehicle with a battery, the method comprising:

monitoring one or more operating conditions of the battery;

comparing one or more of the monitored conditions of the battery to a predetermined state; and

if one or more of the monitored operating conditions of the battery reaches the predetermined state, then turning off a subset of the plurality of speakers.

56. The method of claim 55, wherein the step of monitoring one or more operating conditions of the battery comprises one or more of following:

sensing the output voltage level of the battery,

sensing the discharge current of the battery;

or

sensing the ambient temperature.

57. The method of claim 55, wherein the audio system further comprises a plurality of amplifiers and each of the plurality of speakers is supplied an audio signal provided by one of the plurality of amplifiers, and wherein the step of turning off a subset of the plurality of speakers comprises one of the following steps:

muting the output of an amplifier supplying an audio signal to a speaker,

placing an amplifier supplying an audio signal to a speaker in standby mode,

reducing the voltage of the audio signal input into an amplifier supplying an audio signal to a speaker to approximately zero,

disconnecting the one or more loudspeakers from an amplifier, or

removing electrical power from one or more amplifiers.

58. A method for operating an audio system having one or more equalization signal processes in a vehicle with a battery, the method comprising:

monitoring one or more operating conditions of the battery;

comparing one or more of the monitored conditions of the battery to a predetermined state; and

if one or more of the monitored operating conditions of the battery reaches the predetermined state, then adjusting one or more of equalization signal processes to change the frequency response of the audio system.

59. The method of claim 58, wherein one of the equalization processes includes a high pass filter having a cutoff frequency, and the step of adjusting one or more of the equalization processes comprises raising the cutoff frequency of the high pass filter.

60. The method of claim 58, wherein monitoring one or more operating conditions of the battery comprises one or more of following:

sensing the output voltage level of the battery,

sensing the discharge current of the battery;

or

sensing the ambient temperature.

61. A method for operating an audio system having one or more variable gain elements in a vehicle with a battery, the method comprising:

monitoring one or more operating conditions of the battery;

comparing one or more of the monitored conditions of the battery to a predetermined state; and

if one or more of the monitored operating conditions of the battery reaches the predetermined state, then detecting the level of one or more of audio signals received from an audio source, and dynamically adjusting the gain of one or more variable gain elements as a function of the level of one or more audio signals received from an audio source.

62. The method of claim 61, wherein monitoring one or more operating conditions of the battery comprises one or more of following:

sensing the output voltage level of the battery,

sensing the discharge current of the battery;

or

sensing the ambient temperature.

63. A method for operating an audio system having a plurality of speakers in a vehicle with a battery, the method comprising:

monitoring one or more operating conditions of the battery;

estimating the remaining capacity of the battery based on one or more of the monitored operating conditions of the battery;

comparing the estimated remaining capacity of the battery to a predetermined value; and

if the estimated remaining capacity of the battery is equal to or less than a predetermined value, then causing the audio system to take an action.

64. The method of claim 63, wherein causing the audio system to take an action comprises triggering an alarm indicating that battery capacity is becoming low.

65. The method of claim 63, wherein causing the audio system to take an action comprises causing the automobile to start the engine.

66. The method of claim 63, wherein causing the audio system to take an action comprises reducing the power consumption of the audio system.

67. The method of claim 66, wherein reducing the power consumption of the audio system comprises turning off one or more loudspeakers.

68. The method of claim 66, wherein reducing power consumption of the audio system comprises turning off the system.

69. The method of claim 66, wherein the audio system includes a plurality of equalization processes, and reducing power consumption of the audio system comprises:

receiving an audio signal from an audio source; and

adjusting one or more equalization processes applied to one or more audio signals to change the frequency response of the audio system.

70. A method for operating an audio system in an automobile having a battery and an engine, wherein the audio system includes an audio source that produces a plurality of audio signals and a plurality of loudspeakers, the method comprising:

determining whether the engine is running; and

in response to the system determining that the engine is not running, then changing one or more signal processes to reduce power consumption of the audio system.

71. The method of claim 70, wherein reducing the power consumption of the audio system comprises turning off one or more loudspeakers.

72. The method of claim 71, wherein the audio system includes an amplifier which provides an audio signal to one or more loudspeakers, and the step of turning off one or more of the loudspeakers comprises one of the following steps:

muting the output of the amplifier,

placing the amplifier in standby mode,

reducing the voltage of the audio signal input into the amplifier to approximately zero,

disconnecting the one or more loudspeakers from the amplifier, or

removing electrical power from the amplifier.

73. The method of claim 70, wherein the step of reducing power consumption of the audio system comprises turning off the system.

74. The method of claim 70, wherein said audio system includes one or more equalization processes, and the step of causing the audio system to take an action based on the monitored operating condition of the battery comprises:

receiving one or more audio signals from an audio source; and

adjusting one or more of the equalization processes performed on one or more of the received audio signals to change the frequency response of the audio system.

75. The method of claim 70, wherein the audio system further includes a plurality of variable gain elements and the step of reducing the power consumption of the audio system comprises:

receiving one or more audio signals from the audio source;

detecting the level of one or more of the audio signals, and

dynamically adjusting the gain of one or more variable gain elements as a function of the level of the one or more audio signals.

76. The method of claim 70, wherein each of the plurality of audio signals have an associated signal path, and the step of reducing the power consumption of the audio system comprises reducing the gain in one or more of the signal paths.

77. An audio system for an automobile having a plurality of doors and a battery comprising:

an audio input source;

a plurality of loudspeakers;

a first set of operating conditions for a first mode of operation;

a second set of operating conditions for a second mode of operation, wherein the second set of operating conditions is different from the first set of operating conditions and occurs when one of the doors of the automobile is open; and

a switch for changing between the first and second set of operating conditions.

78. The audio system of claim 77, wherein one of the doors of the automobile is a tailgate and the first set of operating conditions are configured for play while the tailgate is closed and listeners are within the automobile and the second set of operating conditions are configured for play while the tailgate is open and listeners are outside the automobile.

79. The audio system of claim 77, further comprising at least one channel of equalization, wherein the first set of operating conditions defines a first frequency response of the channel of equalization and the second set of operating conditions defines a second frequency response of the channel of equalization.

80. The audio system of claim 77, further comprising:

a dynamic range control device configured to receive an audio signal having a first dynamic range and output an audio signal having a second dynamic range, wherein the second dynamic range is different than the first dynamic range.

81. The system of claim 80, wherein the dynamic range control device comprises:

a variable gain element;

a signal level detector; and

a control element, wherein the control element varies the gain of the variable gain element as a function of the detected signal level.

82. The audio system of claim 77, wherein the first set of operating conditions provides for a first system topology and the second set of operating conditions provides for a second system topology.

83. The audio system of claim 77 further comprising:

at least one input indicating an operating condition of the battery; and

a monitoring process coupled to the at least one input indicating the operating condition of the battery.

84. The audio system of claim 83 wherein the monitoring process is configured to trigger an alarm if the monitored operating condition of the battery the reaches a predetermined state.

85. The audio system of claim 83 wherein the monitoring process is configured to cause the audio system to implement a third set of operating conditions if the monitored operating condition of the battery the reaches a predetermined state.

86. The audio system of claim 85 wherein the third set of operating conditions is configured to reduce the power consumption of the audio system.

87. The audio system of claim 83, wherein the monitoring process is configured to estimate the remaining capacity of the battery.

88. The audio system of claim 85 wherein the monitoring process is configured to trigger an alarm if the estimated remaining capacity of the battery reaches a predetermined state.

89. The audio system of claim 77, wherein the switch is manually controlled by a user.

90. The audio system of claim 77, further comprising input indicating a change in a one or more physical operating conditions of the automobile and wherein the switch is controlled by a change in one or more physical operating conditions of the automobile.

91. The audio system of claim 90, wherein one or more of the physical operating conditions of the automobile is whether a door is opened or closed.

92. The audio system of claim 91 wherein the door is a tailgate.

93. The audio system of claim 77, wherein the system further comprises:

a rear control panel located within the passenger compartment of the automobile towards the back of the automobile, the rear control panel comprises one or more controls for operating the audio system.

94. The audio system of claim 93, wherein the rear control panel further comprises a switch for changing between the first and second set of operating conditions.

95. The audio system of claim 93, wherein the one or more controls for operating the audio system comprise at least one or more of the following:

a volume control, a source selection control, or a source transport control.

96. The audio system of claim 93, wherein the rear control panel further comprises at least one pair of external audio source line level inputs.

97. The audio system of claim 93, wherein the rear control panel further comprises external a microphone level input.

98. The audio system of claim 97, wherein said rear control panel further includes a separate volume control for controlling the level of the external microphone input.

99. The audio system of claim 93, wherein the audio system further comprises an integrated video source and the rear control panel further comprises a separate video output jack for connection to a video display.

100. An audio system for an automobile having a passenger compartment and a tailgate hingidly connected to the top portion of the automobile'"'"'s frame comprising:

a first speaker set comprising a first speaker and a second speaker mounted on the tailgate of the automobile, wherein each speaker in the first set of speakers direct sound along a primary axis of radiation and have a fixed orientation such that each speaker'"'"'s primary axis of radiation directs sound substantially towards the passenger compartment of the automobile when the tailgate is closed, and the speaker'"'"'s primary axis of radiation is pointed away from the passenger compartment of the automobile and is angled relative to the plane of the ground when the tailgate is opened.

101. The audio system of claim 100 wherein the angle is approximately 45 degrees relative to the plane of the ground when the tailgate is opened.

102. The audio system of claim 100, wherein the primary axis of radiation is directed into the passenger compartment at an angle that is approximately 45 degrees relative to the plane of the ground when the tailgate is closed.

103. The audio system of claim 100, wherein the first speaker set is located near an upper edge of the tailgate.

104. The audio system of claim 100, wherein the tailgate includes a window, and wherein the first speaker set is mounted on the tailgate window.

105. The audio system of claim 100 wherein the audio system further comprises a first mode of operation configured for play while the tailgate is closed and listeners are within the automobile and a second mode of operation configured for play while the tailgate is opened and listeners are outside the automobile near the rear of the automobile.

106. The audio system of claim 105, further comprising a second set of speakers comprising a first and second speaker, each speaker having primary axis of radiation that is pointed substantially towards the rear of the automobile and which direct sound outside the automobile in the second mode of operation.

107. An audio system for an automobile having a passenger compartment and a tailgate hingidly connected to the automobile'"'"'s frame and a rear seat or seats having a front portion and a rear portion:

a first speaker set comprising a first speaker and a second speaker mounted on the rear portion of the rear seat or seats, wherein each speaker in the first set of speakers directs sound along a primary axis of radiation and have a fixed orientation such that each speaker'"'"'s primary axis of radiation directs sound substantially away from the passenger compartment of the automobile towards the tailgate when the tailgate is closed, and the speaker'"'"'s primary axis of radiation is pointed away from the passenger compartment of the automobile and directs sound out of the rear of the automobile when the tailgate is opened.

108. An audio system for an automobile having a rear seat, a passenger compartment with a floor, and a tailgate hingidly connected to the automobile'"'"'s frame:

a first speaker set comprising a first speaker and a second speaker mounted on the floor, wherein each speaker in the first set of speakers directs sound along a primary axis of radiation and have a fixed orientation such that each speaker'"'"'s primary axis of radiation directs sound substantially away from the passenger compartment of the automobile towards the tailgate when the tailgate is closed, and the speaker'"'"'s primary axis of radiation is pointed away from the passenger compartment of the automobile and directs sound out of the rear of the automobile when the tailgate is opened.

109. An audio system for an automobile having a rear seat, a passenger compartment with a ceiling, and a tailgate hingidly connected to the automobile'"'"'s frame:

a first speaker set comprising a first speaker and a second speaker mounted on the ceiling, wherein each speaker in the first set of speakers directs sound along a primary axis of radiation and have a fixed orientation such that each speaker'"'"'s primary axis of radiation directs sound substantially away from the passenger compartment of the automobile towards the tailgate when the tailgate is closed, and the speaker'"'"'s primary axis of radiation is pointed away from the passenger compartment of the automobile and directs sound out of the rear of the automobile when the tailgate is opened.

110. An audio system for an automobile having a passenger compartment with a ceiling, floor, and sidewalls, and having a rear opening comprising:

a first speaker set comprising a first speaker and a second speaker mounted within the passenger compartment in the rear half of the automobile, wherein each speaker in the first set of speakers direct sound along a primary axis of radiation and have a fixed orientation such that each speaker'"'"'s primary axis of radiation direct sound substantially towards rear opening of the automobile and wherein the neither speaker in the first speaker set is mounted on a sidewall of the passenger compartment.

111. The audio system of claim 110 wherein the first set of speakers is mounted on the ceiling within the passenger compartment.

112. The audio system of claim 110 wherein the first set of speakers is mounted on the floor within the passenger compartment.