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Automobile audio system

This invention relates to audio systems, and more particularly to audio systems for automobiles.

Audio systems are included in virtually every automobile manufactured today. These audio systems are typically designed for use while the doors, tailgates, and other openings to the passenger compartment are closed. However, people often choose to listen to their automobile audio system while they are outside of their vehicle, such as while they are camping or “tailgating” at a sporting event. Because traditional automobile audio systems are not designed for this type of use, listeners may not enjoy as high a quality sound presentation as they could if the system were designed for outdoor use.

The acoustic characteristics of a typical vehicle with all of its doors closed will generally be significantly different than the acoustic characteristics of the same vehicle with its tailgate (or one of its doors) open. For example, the linear transfer function from each speaker element to various listening locations will be markedly different in each circumstance. Furthermore, opening or closing of the tailgate significantly alters the acoustic characteristics of the cabin space.

Accordingly, it is desirable to have an automobile audio system which is able to operate in two modes: one mode where one or more parameters of the audio system are configured to better optimize sound quality while the doors (to include tailgates) are closed and a second mode where one or more parameters of the audio system are configured to better optimize sound quality while one or more of the doors, such as a tailgate, are open.

Additionally, users may wish to operate their automobile audio system while the engine is not running and thus drain power from the automobile's battery. It is therefore desirable for an automobile audio system to monitor one or more operating conditions of the battery and adjust system performance in order to extend the maximum period of time the audio system can operate from battery power. It is also desirable to monitor one or more operating conditions of the battery to ensure operation of the audio system does not result in a condition where sufficient battery charge (to allow the automobile to be restarted) is no longer available.

It should be noted that the terms automobile and vehicle are used synonymously in this description and refer to any self-propelled passenger vehicle used for land transport, including cars, trucks, pick-up trucks, sport utility vehicles, and the like. Additionally, the term tailgate refers to a hinged door of an automobile which provides access to a rear opening of the automobile. A tailgate may be hingedly connected to the top, bottom, or side of the frame of the automobile.

According to an aspect of the invention, a system and method for operating an audio system in an automobile includes implementing a first system configuration, receiving an input indicating a change in operating mode, and in response to this input, 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, such as a tailgate, of the automobile is open.

Embodiments include one or more of the following features. The first system configuration may occur when all of the doors of the automobile are closed and the second configuration may occur when one or more of the doors, such as a tailgate, are opened.

The audio system may implement a different system topology in the first and second system configurations, where the system topology defines how different signals provided by an audio source are routed to the different speakers of the audio system.

The audio system may implement different signal processing operation in the first and second system configurations. The different signal processing operations in the first and second system configurations may include different equalization signal processing operations, amplification operations, dynamic range control operation, or spatial enhancement operations.

The audio system may also receive input indicating that the automobile's engine is not running, and, in response to this input, the first or second system configuration may be adjusted in order to reduce power consumption of the system. Several adjustments may be made to the first or second system configuration to reduce power consumption including turning off one or more speakers (e.g., by 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, removing electrical power from the amplifier); reducing the gain in one or more of the signal paths; controlling the maximum output power level of the audio system (e.g., by dynamically adjusting the gain of a variable gain element as a function of a detected level of an audio signal); or changing one or more other signal processing operations in the first or second system configuration.

The audio system may switch between the first and second system configuration by monitoring one or more physical conditions of the automobile (e.g., whether a door is opened, the engine is running, or an occupant is in the automobile) and generate a switch command based on a change in one or more of the monitored physical conditions. The audio system may provide a manual switch accessible to a user and change between system configurations based on the state of the switch. The manual switch may be located on a remote control device (e.g., a key fob) or mounted at one or more locations within the automobile (e.g., on a front or rear control panel).

The audio system may also include a battery monitoring process which receives input indicating one or more operating conditions of the battery (e.g., the battery voltage, discharge current, temperature). The battery monitoring process may compare one or more of the monitored operating conditions to a predetermined state, and if the monitored operating conditions reach the predetermined state, then the system would take a responsive action such as triggering an alarm or reducing the power consumption of the audio system. The battery monitoring process may further estimate the remaining capacity of the battery based on one or more of the monitored operating conditions and compare the estimated capacity to a predetermined value, and, if the estimated capacity reaches or falls below the predetermined value, then the system may take a response action such as triggering an alarm or reducing the power consumption of the audio system.

In another aspect, the invention features a method for remotely controlling an audio system in an automobile with a key fob having a plurality of buttons which includes defining a first set of commands corresponding to each button on the key fob, wherein the first set of command includes a command to actuate the door locks. The method also includes defining a second set of commands corresponding to each button, wherein the second set of commands includes one or more commands for controlling the audio system of the automobile. The method further includes switching between the first and second sets of commands based on a predetermined condition.

Embodiments may include one or more of the following features. The key fob may include a switch having two states, and the predetermined condition is a state of the switch. The audio system may have a first mode of operation and a second mode of operation and 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.

In another aspect, the invention features a system and method for operating an audio system in a vehicle with a battery that includes monitoring one or more operating conditions of the battery, comparing one or more of the monitored conditions of the battery to a predetermined state, if the monitored operating conditions of the battery reaches the predetermined state, then triggering an alarm.

Embodiments may include one or more of the following features. The alarm may be an audible alarm, visual alarm, or tactile alarm. One or more of the monitored operating conditions of the battery may include sensing the output voltage level of the battery, sensing the discharge current of the battery; or sensing the ambient temperature.

In another aspect the invention features a system and method for operating an audio system in a vehicle with a battery that includes 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 the monitored operating conditions of the battery reaches the predetermined state, then causing the automobile to start its engine.

In another aspect, the invention features a system and method for operating an audio system in a vehicle with a battery that includes 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 the monitored operating conditions of the battery reaches the predetermined state, then turning off a subset of the plurality of speakers.

In another aspect, the invention features a system and method for operating an audio system in a vehicle with a battery that includes 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 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.