Patent Publication Number: US-9894456-B2

Title: Context-based audio tuning

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 14/146,158 filed Jan. 2, 2014, the disclosure of which is hereby incorporated in its entirety by reference herein. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to a system, apparatus and method for selecting an audio tuning profile based on the content or source of an audio signal. 
     BACKGROUND 
     The listening environment inside a vehicle presents numerous complexities that impact the quality of sound reproduction. The placement of loudspeakers in vehicle listening environments is often less than optimal. Vehicle listening environments are relatively confined and loudspeakers are located in fairly close proximity to a listener. The loudspeakers tend to have various frequency response ranges. It is difficult to locate each loudspeaker the same distance to a listener considering front and rear seat positioning and their proximity to vehicle doors. Moreover, vehicle interiors are irregular in nature and full of materials that absorb or reflect sound, which can result in some frequencies getting muffled while others are amplified. To address these and other complexities, car audio systems are often tuned to optimize the sound stage in a vehicle listening environment. Car audio tuning involves manipulating the frequency profile of audio using equalizers, crossovers, and/or sound processors to achieve an acoustically optimized sound field. Vehicle manufactures usually tune car stereos to a particular seat location, which is most often the driver&#39;s seat, preventing listeners in other seat locations from enjoying a complete audio experience. 
     SUMMARY 
     One or more embodiments of the present disclosure relate to a method for selecting a sound field acoustically optimized at least at one listening position in a vehicle environment. The sound field may be generated by a group of loudspeakers according to audio settings associated with a tuning profile. The group of loudspeakers may include a first loudspeaker and at least a second loudspeaker. The method may include selecting a primary tuning profile based on audio system inputs and transmitting a primary audio signal to the group of loudspeakers according to the primary tuning profile. The method may further include receiving an input indicative of a secondary audio signal and transmitting the secondary audio signal to the group of loudspeakers according to a secondary tuning profile when the secondary audio signal has priority over the primary audio signal. The secondary tuning profile may be selected based at least on the content of the secondary audio signal. 
     Transmission of the primary audio signal to the group of loudspeakers may be interrupted during transmission of the secondary audio signal. Alternatively, the primary audio signal may be attenuated while the secondary audio signal is transmitted to the group of loudspeakers. The primary audio signal may be an entertainment audio signal. Moreover, the primary tuning profile may be selected based on selection input received from a user. 
     The secondary tuning profile may be further selected based on a content source of the secondary audio signal. Moreover, the secondary audio signal may be a navigation prompt received from a navigation system, a vehicle system alert signal received from a vehicle system controller, a traffic alert received from a traffic information system, or a text-to-speech signal corresponding to a text message or an electronic mail message received from a connected mobile device. 
     One or more additional embodiments of the present disclosure relate to a system for selecting an audio tuning profile for providing a sound field acoustically optimized at least at one listening position in a vehicle environment. The sound field may be generated by a group of loudspeakers, including a first loudspeaker and at least a second loudspeaker, according to the audio tuning profile. The system may include a signal source unit configured to transmit audio signals from a plurality of audio sources. The audio signals may include a primary audio signal and at least a secondary audio signal. The system may further include a signal processing unit configured to receive the primary audio signal from the signal source unit and transmit the primary audio signal to the group of loudspeakers according to a primary tuning profile. The signal processing unit may be further configured to receive the secondary audio signal from the signal source unit when the secondary audio signal has priority over the primary audio signal. The signal processing unit may be further configured to select a secondary tuning profile based on content of the secondary audio signal and transmit the secondary audio signal to the group of loudspeakers according to the secondary tuning profile. 
     The signal processing unit may be integrated with an amplifier. The signal processing unit may also include a memory unit having at least a first set of audio settings associated with the primary tuning profile and a second set of audio settings associated with the secondary tuning profile. The second set of audio settings may be different from the first set of audio settings. The signal processing unit may further include an audio post-processing module that applies the first set of audio settings to the primary audio signal and the second set of audio settings to the secondary audio signal. 
     The primary audio signal may be temporarily interrupted during transmission of the secondary audio signal. Alternatively, the primary audio signal may be attenuated during transmission of the secondary audio signal. The primary audio signal may be an entertainment audio signal. Moreover, the secondary audio signal may be a vehicle alert or prompt. The secondary audio signal may also be a text-to-speech signal corresponding to a text message or an electronic mail message received from a connected mobile device. 
     One or more additional embodiments of the present disclosure relate to an audio signal processing and amplification device. The audio signal processing and amplification device may include a streaming interface configured to receive audio data signals from a signal source unit. The audio data signals may originate from a plurality of audio sources. The audio signal processing and amplification device may further include a command interface configured to receive audio command signals corresponding to the audio data signals from the signal source unit. The audio command signals may include an audio tuning profile command. The audio signal processing and amplification device may further include a memory unit configured to store a plurality of audio tuning profiles. Each audio tuning profile may include audio settings for generating a sound field acoustically optimized at least at one listening position in a vehicle environment. 
     Additionally, the audio signal processing and amplification device may include an audio post-processing module configured to receive the audio data signals and corresponding audio command signals and retrieve an audio tuning profile from the plurality of audio tuning profiles based on the audio tuning profile command. The audio post-processing module may be further configured to process the audio data signals according to the audio settings associated with the audio tuning profile and transmit the processed audio data signals to a group of loudspeakers. The group of loudspeakers may include a first loudspeaker and at least a second loudspeaker. Transmitting the processed audio data signal to the group of loudspeakers may generate the acoustically optimized sound field associated with the audio tuning profile based on the content of the audio data signals. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a simplified, exemplary block diagram of an audio system, in accordance with one or more embodiments of the present disclosure; 
         FIG. 2  is a simplified, exemplary block diagram of a signal processing unit, in accordance with one or more embodiments of the present disclosure; 
         FIG. 3  depicts an exemplary audio tuning profile for a vehicle, in accordance with one or more embodiments of the present disclosure; 
         FIG. 4  depicts another exemplary audio tuning profile for a vehicle, in accordance with one or more embodiments of the present disclosure; 
         FIG. 5  is a flow diagram depicting a method for selecting a sound field acoustically optimized at least at one listening position in a vehicle environment, in accordance with one or more embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     In the following detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. The illustrative embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the Figures, may be arranged, substituted, combined, and designed in a wide variety of different configurations, all of which are explicitly contemplated and make part of this disclosure. 
       FIG. 1  depicts an exemplary audio system  100  for delivering multimedia content in a vehicle environment. The audio system  100  may include a signal source unit  102 , a signal processing unit  104 , and a plurality of loudspeakers  106 . The plurality of loudspeakers  106  may include a first loudspeaker and at least a second loudspeaker. For ease of explanation, the exemplary audio system illustrated in  FIG. 1  is configured to provide 5.1 channel surround sound. Accordingly, the plurality of loudspeakers  106  may include a front left loudspeaker  106   a , a front right loudspeaker  106   b , a front center loudspeaker  106   c , a rear left loudspeaker  106   d , a rear right loudspeaker  106   e , and a subwoofer  106   f . However, one or more embodiments of the present disclosure may be implemented using any number of multi-channel audio set-ups, such as 4.0 channel, 7.1 channel, and the like. 
     The plurality of loudspeakers  106  may include one or more groups of loudspeakers  106 , with each group of loudspeakers assigned to at least one listening position in a vehicle passenger compartment for generating a sound field. The signal source unit  102  may provide an audio signal to each loudspeaker using a respective audio channel. The signal processing unit  104  may perform a number of audio post-processing functions that can be applied to at least one audio channel  108  supplying a loudspeaker  106 . Such audio post-processing functions may include introducing speaker delays, performing graphic and parametric audio equalization, controlling audio tone (e.g., bass, mid-range, or treble), audio balancing and fading, controlling individual audio channel volume, muting or unmuting individual audio channels, audio mixing, or the like. The preceding list of audio post-processing functions is merely indicative of the capabilities of the signal processing unit  104 , and not exhaustive. The signal processing unit  104  may be capable of performing additional audio post-processing functions not specifically mentioned without departing from the scope of the present disclosure. 
     As shown in  FIG. 1 , the signal source unit  102  may communicate with the signal processing unit  104 . For instance, the signal source unit  102  may deliver audio data signals  110  to the signal processing unit  104 . The signal processing unit  104  may perform or apply one or more of the number of audio post-processing functions to the audio data signals  110  to obtain a number of processed audio signals  112 . The signal processing unit  104  may then deliver one or more of the number of processed audio signals  112  to a group of loudspeakers  106  via their respective audio channels  108 . The digital signal processing applied to the audio data signals  110  may differ between respective audio channels  108  so that a particular sound field may be acoustically optimized at least at one listening position. Accordingly, the signal source unit  102  and the signal processing unit  104  may also exchange audio command signals  114 . The audio command signals may include control commands from the signal source unit  102  to the signal processing unit  104 , as well as feedback signals from the signal processing unit  104  to the signal source unit  102 . 
     The control commands may instruct the signal processing unit  104  to apply one or more of the audio post-processing functions to the corresponding audio data signals  110 . The control commands may include signal processing parameters to be applied on a channel-by-channel basis. Alternatively, the signal processing unit  104  may maintain a number of audio tuning profiles in memory. Each audio tuning profile may include audio settings to be applied to an audio data signal  110  by the signal processing unit  104 . In this manner, the audio command signal  114  may contain a control command for instructing the signal processing unit  104  on which audio tuning profile to apply to the corresponding audio data signals  110 . The control command may be an audio tuning profile identifier or it may be an audio content or source identifier such that the signal processing unit  104  knows which audio tuning profile settings to retrieve from memory. The processed audio signals  112  may then be delivered via their respective audio channels  108  to a corresponding group of loudspeakers  106  to generate a sound field acoustically optimized at least at one listening position in a vehicle environment based on the selected audio tuning profile. 
     Though illustrated separately in  FIG. 1 , the signal processing unit  104  may be integrated with or internal to the signal source unit  102 . Moreover, the signal processing unit  104  may be an amplifier or integrated with an amplifier to provide an audio signal processing and amplification device. Such an amplifier may likewise be internal or external with respect to the signal source unit  102 . Whether integrated or separate devices, the signal source unit  102  and the signal processing unit  104  may be collectively referred to as an infotainment system  116 . 
     According to one or more embodiments of the present disclosure, the signal source unit  102  may be an infotainment head unit configured to provide audio/video playback, navigation, and telematics-based services. To this end, the infotainment system  116  may include such functions as AM/FM, digital or satellite radio, compact disc (CD) or digital video disc (DVD) playback, multimedia accessories, rear seat entertainment, camera integration, Bluetooth connectivity, and telecommunications connectivity. The signal source unit  102  may include a plurality of antennas, collectively represented in  FIG. 1  as antenna  118 . The plurality of antennas  118  may include various radio antennas (e.g., AM, FM, satellite, etc.), a Bluetooth antenna, a global positioning system (GPS) antenna, as well as other vehicle telecommunications antennas for performing various telematics-based services and the like. In addition to GPS-based navigation, other telematics-based communications may involve integrated hands-free cell phones, wireless vehicle safety communications, emergency warning systems, mobile Internet, traffic and weather reports, or the like. 
     Further, the signal source unit  102  may include a human-machine interface (HMI)  120  to provide a user access to select and control the various functions available. The signal source unit HMI  120  may include a plurality of input buttons, knobs, and the like (not shown). The HMI  120  may also include a graphical user interface (GUI) (not shown). The GUI may include touch-screen technology for receiving additional user input. One or more mobile devices  122  may be connected to the signal source unit  102  by wire through a universal serial bus (USB), auxiliary, or other dedicated port. Alternatively, a mobile device  122  may be connected to the signal source unit  102  wirelessly, such as via Bluetooth pairing. Accordingly, in the present disclosure, a general reference to a connected mobile device may encompass both wired and wireless connections to the signal source unit  102 . 
     Though described as a signal source unit  102 , the term should not be interpreted to mean that all audio content necessarily originated from within the signal source unit  102 . Rather, the signal source unit  102  may receive original audio content from external sources or devices, such as a connected mobile device  122 . Further, the signal source unit  102  may deliver audio data signals  110  in response to information received from external traffic information systems or weather information systems, GPS satellites, or the like (not shown). Thus, as used herein, the signal source unit  102  may refer to an apparatus that delivers audio data signals  110  to the signal processing unit  104 , whether internal or external, for distribution to one or more of the plurality of loudspeakers  106  via their respective audio channels  108 . Moreover, although one or more embodiments are disclosed in the context of a full-feature infotainment head unit for purposes of description, such embodiments are exemplary only. The signal source unit  102  may also be embodied in various other types of car audio head units, including those with lesser capabilities such as car stereo receivers lacking integrated navigation or Bluetooth functionality. 
     The signal processing unit  104  is shown in greater detail in  FIG. 2 . As previously described, the signal processing unit  104  may be integrated with an amplifier to provide an audio signal processing and amplification device. Further, the signal processing unit  104  may be internal to the signal source unit  102  or it may be an external device in communication with the signal source unit  102 . As shown in  FIG. 2 , the signal processing unit  104  may include a multi-signal interface for communicating with the signal source unit  102 . For instance, the signal processing unit  104  may include a streaming interface  202  configured to receive audio data signals  110  from the signal source unit  102 . The incoming audio data signals  110  may be pulse-code modulated signals. Pulse-code modulation (PCM) is a technique used to digitally represent sampled analog signals and is a format commonly employed in digital audio applications. 
     The streaming interface  202  may be configured to receive compressed or streams of audio data using an infotainment networking technology standard such as Media Oriented Systems Transport (MOST), Audio Video Bridging (AVB), or the like. If the streaming interface  202  is of an analog type, it may include an analog-to-digital converter (ADC) (not shown). In this manner, the signal source unit may convert  102  may convert digital audio to analog using a digital-to-analog converter (DAC) and send the converted audio to the signal processing unit  104 . The streaming interface  202  may convert the audio back to digital format using the ADC. 
     As part of its multi-signal interface, the signal processing unit  104  may also include a command interface  204  configured to receive audio command signals  114  corresponding to the audio data signals  110  from the signal source unit  102 . The command interface  204  may be configured to receive the audio command signals  114  using any number of communication bus protocols, such as Inter-Integrated Circuit (I2C), Controller Area Network (CAN), or the like. As previously described, the audio command signals  114  may include control commands instructing the signal processing unit  104  to apply one or more audio post-processing functions to the corresponding audio data signals  110 . Alternatively, the audio command signals  114  may include an audio tuning profile command instructing the signal processing unit  104  to apply a specific audio tuning profile having preset audio settings stored in memory. As another alternative, the audio command signal  114  may include an audio signal source or content identifier that may be used by the signal processing unit  104  to select a suitable audio tuning profile to apply to the audio data signals  110 . 
     According to one or more embodiments, the streaming interface  202  and the command interface  204  may be combined into a single-signal interface. As such, the audio data signals  110  may include command headers instructing the signal processing unit  104  which audio settings to apply to the audio data signals. Such a single-signal interface may be employed, for example, using MOST or AVB technology. 
     The signal processing unit  104  may include a memory unit  206  for storing a plurality of audio tuning profiles  208 . Each audio tuning profile  208  may include audio settings  210  for generating a sound field acoustically optimized at least at one listening position in a vehicle environment. For instance, one audio tuning profile  208  may include audio settings  210  for generating a sound field acoustically optimized at the driver seat.  FIG. 3  is a simplified, exemplary diagram of a vehicle  302  symbolically depicting the aforementioned scenario in which the audio settings  210  are tuned for a user located in the driver seat, S 1 , of a vehicle passenger compartment  304 . Accordingly, in the present disclosure, an audio tuning profile with these audio settings may be referred to as Profile S 1 . Profile S 1  may be activated for audio corresponding to navigation prompts, vehicle system alert signals or prompts (e.g., park distance controls, back-up alerts, seat belt alarms, door ajar alarms, etc.), or the like. Profile S 1  is depicted in  FIG. 3  using speaker delays δ 1 , δ 2 , δ 3 , and δ 4  applied to the front right loudspeaker, rear right loudspeaker, rear left loudspeaker and center loudspeaker channels, respectively. However, the representation of Profile S 1  in  FIG. 3  using δ 1 , δ 2 , δ 3 , and δ 4  is symbolic of all audio settings  210  associated with Profile S 1 . 
     The vehicle  302  may also include additional listening positions associated the other seating locations, S 2 -S 5 .  FIG. 4  shows another simplified, exemplary diagram symbolically depicting audio settings  210  for generating a sound field acoustically optimized at a front passenger seat, S 2 . An audio tuning profile with these audio settings may be referred to as Profile S 2 . Profile S 2  may include audio settings  210  suitable for playback of audio from multimedia sources, as well as for electronic mail (email) or Subscriber Messenger Service (SMS) message readouts from connected mobile devices, or the like. The memory unit  206  may store additional audio tuning profiles  208  for generating sound fields acoustically optimized at each of the remaining seat locations, S 3 , S 4  and S 5 , referred to as Profile S 3 , Profile S 4  and Profile S 5 , respectively. While the vehicle  302  shown in  FIGS. 3 and 4  is depicted having a passenger compartment  304  with two rows of seating, such as in a sedan or coupe, one or more embodiments of the present disclosure are equally applicable to vehicles with any number of seating configurations. 
     The memory unit  206  may also store audio tuning profiles  208  for generating sound fields acoustically optimized for multiple listening positions. For instance, one or more audio tuning profiles  208  may be programmed with audio settings  210  optimized for multiple passengers to experience audio entertainment sources. One such audio tuning profile  208  may include audio settings  210  for generating a sound field acoustically optimized for all listening positions in the vehicle  302 . Another such audio tuning profile  208  may include audio settings  210  for generating a sound field acoustically optimized for all listening positions in a front passenger compartment  304   a  of the vehicle  302 . Yet another such audio tuning profile  208  may include audio settings  210  for generating a sound field acoustically optimized for all listening positions in a rear passenger compartment  304   b  of the vehicle  302 . 
     In the case of a factory infotainment system  116  installed by a vehicle manufacturer, the audio tuning profiles  208  may be preprogrammed by the vehicle manufacturer, or a supplier to the vehicle manufacturer, with audio settings  210  optimized for the particular vehicle in which the infotainment system is being installed. For aftermarket infotainment systems  116 , a set of one or more audio tuning profiles  208  for each of a number of available vehicles may be stored in the memory unit  206 . Once installed, a user may select the vehicle make and model from a settings menu via the signal source unit&#39;s HMI  120  so that the signal source unit  102  or the signal processing unit  104  knows which set of audio tuning profiles  208  to apply. Alternatively, a user may select the vehicle in which the infotainment system  116  is installed, and, if available, a set of audio tuning profiles  208  configured for the selected vehicle may be downloaded to the signal source unit  102  or the signal processing unit  104 . The appropriate set of audio tuning profiles  208  may also be downloaded remotely and installed in the signal source unit  102  or signal processing unit  104  using an external storage device, such as a memory stick via a USB port. 
     As yet another alternative, the infotainment system  116  may be configured to perform real-time, in-vehicle measurement of listening positions to capture optimal audio settings  210 . During the initial setup, the signal processing unit  104  may collect audio data on a number of different listening positions and may generate an optimized audio tuning profile  208  for each location. The audio data may be collected, for example, using binaural microphones worn by a user or a mannequin. During system configuration, the signal processing unit  104  may also be configured to measure multiple listening positions and balance the audio output between two or more seat locations. Once the initial setup is complete, the audio tuning profiles  208  may be stored in the memory unit  206  and the corresponding audio settings  210  may be applied to subsequent audio delivered to the signal processing unit  104 . 
     Referring back to  FIG. 2 , the memory unit  206  may store a number of audio settings  210  associated with each tuning profile  208 . The audio settings  210  may include various parameters to be applied to the audio data signals  110  by an audio post-processing module  212 . Such parameters may include loudspeaker delay units, filter coefficients, volume/mute curves, source/sink connections, frequency level adjustments, or the like. Thus, the audio post-processing module  212  may perform one or more of the exemplary audio post-processing functions previously described. Further, the audio post-processing module  212  may use a digital signal processor (DSP) for applying DSP-based audio post-processing functions. The digitally-processed audio data signals  110  may then be delivered to one or more of the audio channels  108  according to the active audio tuning profile  208 . As shown, each audio channel  108  may include a digital-to-analog converter (DAC)  214 , which converts the digital audio information into an analog signal that can be played by the loudspeaker  106  associated with the respective audio channel  108 . 
     The infotainments system  116  may be configured to receive input indicative of a user selection of one of the audio tuning profiles  208  via the HMI  120  provided with the signal source unit  102 . According to one more embodiments of the present disclosure, the infotainment system  116  may be configured to automatically select an audio tuning profile  208  to apply to the audio data signals  110 . The infotainment system  116  may select an audio tuning profile  208  based on a number of factors including, for example, seat occupancy detection, paired or otherwise connected mobile devices  122 , or the like. The infotainment system  116  may detect occupancy of a passenger seat using occupancy detection techniques know to one of ordinary skill in the art. Such exemplary occupancy detection techniques may employ capacitive sensors, seat pressure sensors, optical or infrared cameras, or the like. 
     As previously described, the audio data signals  110  transmitted from the signal source unit  102  may be generated based on content received from at least one of a plurality of content sources. A content source may be a compact disc, a radio station, a traffic or weather information system, a connected mobile device  122 , a navigation system, a connected vehicle control module (e.g., via a controller area network (CAN) bus), or the like. Thus, the content received from a content source may not necessarily include the same audio data contained in the audio data signals received by the signal processing unit  104 . Rather, in some instances, the content received by the signal source unit  102  may include other information and the signal source unit  102  may generate an audio data signal  110  to convey the information, or related information, to a user audibly using prompts, alerts, messages, or the like. For instance, the signal source unit  102  may output an audible navigation prompt based on map data and coordinate data received from a GPS antenna. Similarly, the signal source unit  102  may convert text from an email to speech so that, when prompted, the email message may be communicated to a user as an audible message. 
     According to one or more embodiments of the present disclosure, the infotainment system  116  may also select an audio tuning profile  208  to apply to an audio data signal  110  based on the content of the audio data signal, the content source of the audio data signal, or both. In this manner, the post-processing applied by the signal processing unit  104  to incoming audio data signals  110  may be context-based. For instance, a user sitting next to the driver in seat S 2  may pair, synchronize or otherwise connect a mobile device  122  to the signal source unit  102 . This user may select Profile S 2  on the signal source unit  102 . Alternatively, the infotainment system  116  may automatically detect the presence of the user in seat S 2  from a camera, seat sensor, audio or any other sensor information for occupancy detection. The infotainment system  116  may then load the audio settings  210  associated with Profile S 2  suitable for generating a sound field acoustically optimized at seat location S 2 . 
     When the user starts streaming music from the connected mobile device  122 , the user located at seat S 2  may experience the audio optimally. If the user elects to have an SMS message or email read aloud from the mobile device  122 , the infotainment system  116  may, for example, play the converted text-to-speech on a loudspeaker  106  nearest the user&#39;s seat location at an optimal volume while muting or attenuating all the other loudspeakers. Thus, according to one or more embodiments, each seat location may be associated with multiple audio tuning profiles  208  selectable based on the content of the audio. For example, as explained above, at least one audio tuning profile  208  associated with seat S 2  may be selected for audio data signals  110  containing music, while another audio tuning profile  208  associated with seat S 2  may be selected to output text messages from the user&#39;s mobile device  122  as speech. 
     Continuing the above example, when a vehicle system alert signal (e.g., a navigation prompt, traffic alert, safety alert, etc.) is received by the signal source unit  102 , the infotainment system  116  may load Profile S 1  corresponding to the driver&#39;s seat location, S 1 , so that the audible prompts can be optimally heard by the driver. Once the alert prompt is completed, Profile S 2  may be re-loaded and the user located at seat S 2  may continue to enjoy the audio experience of a sound field acoustically optimized for seat S 2 . 
     As another example, an audio tuning profile  208  having audio settings  210  for generating a sound field acoustically optimized for multiple seat locations may be selected, either automatically or by a user, so that audio from an audio entertainment source may be optimally experienced by multiple passengers. The audio entertainment source may be a radio station, a CD, a connected mobile device, or the like. If a user of a connected mobile device  122  authorizes an email or SMS message to be read aloud as speech, the infotainment system  116  may automatically select an audio tuning profile  208  acoustically optimized for the user&#39;s seat location while the message is played through one or more loudspeakers  106 . Once the message is finished playing, the initial audio tuning profile may be re-loaded and applied to the audio from the audio entertainment source. If an alert prompt is received during playback of either the entertainment audio signal or the email/SMS message, the alert audio may take priority. Accordingly, the infotainment system  116  may select Profile S 1  optimized for the driver in order to play the audible vehicle system alert (e.g., traffic alert, navigation prompt, etc.). 
       FIG. 5  is a flow diagram depicting an exemplary method  500  for selecting a sound field acoustically optimized at least at one listening position in a vehicle environment based on the content of an audio data signal. As shown at step  505 , the infotainment system  116  may receive a number of audio system inputs. The audio system inputs may be indicative of audio content selection, connected systems and devices, user playback settings, or the like. The signal source unit  102  may transmit a primary audio signal to the signal processing unit  104  based on the audio content selection. For instance, the primary audio signal may correspond to entertainment audio such as that read from a CD, received from a radio broadcast, streamed from the Internet or a connected mobile device, or the like. The audio system inputs may further include input indicative of an audio tuning profile  208  to be applied to the primary audio signal. 
     At step  510 , the infotainment system  116  may determine whether an audio tuning profile  208  has been selected for the primary audio signal. If no audio tuning profile  208  has been selected by the infotainment system  116  based on the audio system inputs, the method may proceed to step  515 . At step  515 , the infotainment system  116  may select an audio tuning profile  208  to apply to the primary audio signal in the absence of a user selection. The audio tuning profile  208  may be automatically selected by the infotainment system  116  based on audio system inputs. For instance, the infotainment system  116  may detect the presence of an occupant in a particular listening position or an occupant&#39;s connect mobile device  122 , or both, and may select a particular audio tuning profile  208  accordingly. Alternatively, the infotainment system  116  may select a default audio tuning profile  208  in the absence of a user-selected profile. The audio tuning profile  208 , selected automatically or based on user input, may be referred to as the primary tuning profile. The primary tuning profile may include primary audio settings for generating a sound field acoustically optimized at least at one listening position for playback of the primary audio signal. 
     At step  520 , the primary tuning profile including the primary audio settings to be applied to the primary audio signal may be loaded. Loading the primary tuning profile may include receiving a primary audio command signal containing the primary audio settings to be applied to the primary audio signal by the signal processing unit  104 . Alternatively, loading the primary tuning profile may include receiving a primary audio command signal identifying which audio tuning profile  208  to apply to the corresponding primary audio signal and retrieving the primary audio settings to be applied from the memory unit  206 . At step  525 , the infotainment system  116  may transmit the primary audio signal to a group of loudspeakers  106  according to the primary tuning profile. 
     Turning to step  530 , the infotainment system  116  may determine whether input indicative of a secondary audio signal is present. If no secondary audio signal is detected, the method may return to step  525  and the primary audio signal may continue to be delivered to the group of loudspeakers  106  according to the primary tuning profile. If, however, the presence of a secondary audio signal is detected, the method may proceed to step  535 . At step  535 , the infotainment system  116  may determine whether the secondary audio signal has a higher priority than the primary audio signal. For instance, vehicle system alerts and prompts may have a higher priority than text-to-speech content from a connected mobile device  122 . In turn, the text-to-speech content received from the connected mobile device  122  may take priority over entertainment audio signal content such as music playback. Therefore, if the primary audio signal is a spoken email or SMS message and the secondary audio signal has lower priority, the primary audio signal may continue without interruption. If, for example, the secondary audio signal is a navigation prompt, however, the secondary audio signal may take priority. If the primary audio signal has a higher priority than the secondary audio signal, the method may return to step  525  and the primary audio signal may continue to be delivered to the group of loudspeakers  106  according to the primary tuning profile. On the other hand, if the secondary audio signal has a higher priority than the primary audio signal, the method may proceed to step  540 . 
     Similar to step  520 , the secondary tuning profile including secondary audio settings to be applied to the secondary audio signal may be loaded at step  540 . According to one or more embodiments of the present disclosure, the secondary tuning profile may be selected based on the content of the secondary audio signal, the source of the secondary audio signal, or both. For instance, if the secondary audio signal is a vehicle system alert, traffic alert, navigation prompt or the like, the infotainment system  116  may select and load Profile S 1  as the secondary tuning profile so that the sound field can be acoustically optimized for the seat position, S 1 , belonging to the driver. As another example, if the secondary audio signal is a text-to-speech signal corresponding to an SMS message or an email message from a user&#39;s connected mobile device  122 , the infotainment system  116  may select and load an audio tuning profile associated with the seat location of the user. 
     At step  545 , the infotainment system  116  may transmit the secondary audio signal to a group of loudspeakers  106  according to the secondary tuning profile. According to one or more embodiments, the primary audio signal may be completely interrupted in lieu of the secondary audio signal when the secondary audio signal has priority over the primary audio signal. Alternatively, the primary audio signal may be attenuated at one or more of the loudspeakers  106  in favor of the secondary audio signal. 
     At step  550 , the infotainment system  116  may determine whether delivery of the secondary audio signal has been completed. If delivery of the secondary audio signal is not complete, the method may return to step  545  and so that delivery of the secondary audio signal may continue. If, however, delivery of the secondary audio signal is complete, the method may return to step  525  and the primary audio signal may continue to be delivered to the group of loudspeakers  106  according to the primary tuning profile. 
     While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the disclosed subject matter. 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 subject matter presented herein. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the present disclosure.