Patent Description:
This disclosure generally relates to automobile sound stage control. More particularly, the disclosure relates to approaches and related systems for controlling the phantom center image of an audio output in an automobile.

In some automobile audio systems, processing is applied to the audio signals provided to each speaker based on the electrical and acoustic response of the total system, that is, the responses of the speakers themselves and the response of the vehicle cabin to the sounds produced by the speakers. Such a system is highly individualized to a particular automobile model and trim level, taking into account the location of each speaker and the absorptive and reflective properties of the seats, glass, and other components of the car, among other things. Such a system is generally designed as part of the product development process of the vehicle and corresponding equalization and other audio system parameters are loaded into the audio system at the time of manufacture or assembly.

Conventional automobile audio systems, with stereo speakers in front of and behind the front seat passengers, include controls generally called fade and balance. The same stereo signal is sent to both front and rear sets of speakers, and the fade control controls the relative signal level of front and rear signals, while the balance control controls the relative signal level of left and right signals. While fade and balance control permit users to modify some aspects of the automobile audio output, conventional automobile audio systems do not allow users to make additional modifications to the audio output, such as center image placement, stereo image width and/or presentation of uncorrelated content. These limited controls can hinder the user experience.

<CIT>, <CIT> and <CIT> illustrate relevant prior art in the field.

The above-mentioned drawbacks are solved with a method according to claim <NUM> and an audio system according to claim <NUM>. Optional features of the method and system are defined in the corresponding dependent claims.

In certain aspects, the designated position of sound produced by the set of speakers in the audio system is detectable by a user and includes an inter-aural phase and inter-aural level as perceived by the user that is consistent with a source from the designated position.

In some implementations, the phantom center image is initially set to a default designated position. In particular cases, the default designated position is defined by a user or according to a characteristic of the automobile.

In certain aspects, the at least one user interface command includes a control value command for shifting the phantom center image of the audio output.

In particular cases, the perceived location of the phantom center image of the audio output is adjusted by modifying a filter weight on at least one speaker in the audio system.

In some implementations, the perceived location of the phantom center image is adjustable across a range of pre-defined angles, the adjusting including matching the at least one user interface command to a nearest one of the pre-defined angles to provide the adjusted perceived location of the phantom center image of the audio output.

In particular aspects, the user interface command includes a user profile command or a preset command attributed to a user of the automobile, where the user profile command or the preset command is obtained from an identification file attributed to the user.

In some cases, adjusting the perceived location of the phantom center image of the audio output includes adjusting at least one of a center image azimuth angle of the audio output, a center image distance of the audio output or a center image elevation of the audio output.

In certain implementations, the computer-implemented method further includes: receiving at least one additional user interface command to modify at least one of a left channel output, a right channel output or content produced through an up-mixing of an audio system signal or additional audio channels across the audio system; and adjusting an additional spatial placement of the audio output from the audio system based upon the at least one additional user interface command.

In particular cases, the control system is further configured to: apply a first set of filters that causes sound produced by the set of speakers to have characteristics at an intended position of a user's head of sound produced by a sound source located at a first designated position other than the physical locations of the set of speakers; and in response to the at least one user interface command, apply a second set of filters that causes sound produced by the set of speakers to have characteristics at the intended position of the user's head of sound produced by a sound source located at a second designated position other than the physical locations of the set of speakers and different from the first designated position.

In certain implementations, the control system is further configured to: receive at least one additional user interface command to modify at least one of a left channel output, a right channel output or a phase difference across the set of speakers; and adjust an additional spatial placement of the audio output from the set of speakers based upon the at least one additional user interface command.

Other features, objects and benefits will be apparent from the description and drawings, and from the claims.

It is noted that the drawings of the various implementations are not necessarily to scale. The drawings are intended to depict only typical aspects of the disclosure, and therefore should not be considered as limiting the scope of the implementations.

This disclosure is based, at least in part, on the realization that a control system can be beneficially incorporated into an automobile audio system. For example, an automobile audio system can be programmatically controllable to modify aspects of a soundstage in the automobile, such as the placement of the phantom center image, the width of the stereo image or presentation of uncorrelated content. The system and related method can significantly improve the user experience when compared with conventional automobile audio systems.

Commonly labeled components in the FIGURES are considered to be substantially equivalent components for the purposes of illustration, and redundant discussion of those components is omitted for clarity.

Conventional car audio systems are based around a set of four or more speakers, two on the instrument panel or in the front doors and two generally located on the rear package shelf, in sedans and coupes, or in the rear doors or walls in wagons and hatchbacks. The audio system <NUM> shown in <FIG> depicts a wagon or hatchback configuration including a speaker on each of the four doors. It is understood that this configuration is only one example of an audio system used to illustrate various implementations of the disclosure, and that a variety of additional configurations can be utilized with these implementations.

Audio system <NUM> is shown including a combined source/processing/amplifying unit <NUM>. In some examples, the different functions may be divided between multiple components. In particular, the source is often separated from the amplifier, and the processing is provided by either the source or the amplifier, though the processing may also be provided by a separate component. The processing may also be provided by software loaded onto a general purpose computer providing functions of the source and/or the amplifier. We refer to signal processing and amplification provided by "the system" generally, without specifying any particular system architecture or technology.

The audio system <NUM> shown in <FIG> has four sets of speakers <NUM>, <NUM>, <NUM>, <NUM> permanently attached to the vehicle structure. We refer to these as "fixed" speakers. In the example of <FIG>, each set of fixed speakers includes two speaker elements, commonly a tweeter <NUM>, <NUM>, <NUM>, <NUM> and a low-to-mid range speaker element <NUM>, <NUM>, <NUM>, <NUM>. In another common arrangement, the smaller speaker is a mid-to-high frequency speaker element and the larger speaker is a woofer, or low-frequency speaker element. The two or more elements may be combined into a single enclosure or may be installed separately. The speaker elements in each set may be driven by a single amplified signal from the source/processing/amplifying unit <NUM>, with a passive crossover network (which may be embedded in one or both speakers) distributing signals in different frequency ranges to the appropriate speaker elements. Alternatively, the source/processing/amplifying unit <NUM> may provide a band-limited signal directly to each speaker element. In other examples, full range speakers are used, and in still other examples, more than two speakers are used per set. Each individual speaker shown may also be implemented as an array of speakers, which may allow more sophisticated shaping of the sound, or simply a more economical use of space and materials to deliver a given sound pressure level.

As described herein, the source/processing/amplifying unit <NUM> can include (or be coupled with) a control system <NUM> configured to aid in controlling the audio output in the audio system <NUM>. In particular implementations, as described herein, control system <NUM> is configured to adjust a perceived location of the phantom center image of the audio output from audio system <NUM>. The perceived location of the phantom center image is the location from which the synthesized output of the speakers <NUM>, <NUM>, <NUM>, <NUM> appears to originate. In certain cases, the phantom center image sounds as though it is originating from the same physical distance between the listener and the directionally nearest physical speaker <NUM>, <NUM>, <NUM>, <NUM>. This phantom center image can be differentiated from many uses of "virtual" speakers, which rely upon near field (headrest-type) speakers to produce a sound that appears to originate from a location at which speakers are not physically present. This virtual speaker configuration often adds distance from the listener to the physical speaker (e.g., the near field speaker), which makes the virtual speaker configuration sound less like a naturally occurring playback than a phantom center image in an automobile setting.

While the control system <NUM> can include hardware and/or software for controlling signal processing and additional functions described herein, it is understood that one or more aspects of the control system <NUM> (and its corresponding functions) can be implemented using one or more remote computing devices (e.g., cloud computing devices) which are programmatically linked with the source/processing/amplifying unit <NUM>. As noted herein, the control system <NUM> can include any software-based, electrical and/or electro-mechanical control configuration capable of receiving control instructions (e.g., via an interface or other communication protocol) and adjusting a perceived location of the phantom center image of the audio output from audio system <NUM> (including speakers <NUM>, <NUM>, <NUM>, <NUM>) via the source/processing/amplifying unit <NUM>.

Control system <NUM> may actuate adjustment of the perceived location of the phantom center image in response to a command received locally, e.g., at an interface <NUM> such as a user interface (UI) or application programming interface (API), or via a network-connected device. An example interface <NUM> is illustrated in <FIG>. It is understood that this interface <NUM> is shown in phantom because the interface may be integrated into the control system <NUM>, part of an existing control interface for the audio system <NUM>, or part of any linked interface (e.g., a software application interface) for providing an interface command to control system <NUM>. In particular implementations, the control system <NUM> can be configured to receive commands via interface <NUM>, either directly or from a network connected device such as a remote control, smartphone, tablet, wearable electronic device, voice-controlled command system, etc., and may communicate over any network connection (e.g., cloud-based or distributed computing system).

<FIG> shows two user's (or, listener's) heads <NUM>, <NUM> as they are expected to be located relative to the speakers <NUM>, <NUM>, <NUM>, <NUM> (shown in simplified view in <FIG>, and in greater detail in <FIG>). Heads <NUM>, <NUM> of users are illustrated relative to the automobile seats <NUM>, <NUM>, which each include a base and a back. Driver <NUM> has a left ear <NUM> and right ear <NUM>, and the ears of passenger <NUM> are labeled <NUM> and <NUM>. Dashed arrows show various paths sound takes from the speakers <NUM>, <NUM>, <NUM>, <NUM> to the user's ears <NUM>, <NUM> and <NUM>, <NUM> as described below. We refer to these arrows as "signals" or "paths," though in actual practice, we are not assuming that the speakers can control the direction of the sound they radiate, though that may be possible. Multiple signals assigned to each speaker <NUM>, <NUM>, <NUM>, <NUM> are superimposed to create the ultimate output signal, and some of the energy from each speaker may travel omnidirectionally, depending on frequency and the speaker's acoustic design. The arrows merely show conceptually the different combinations of speaker and ear for easy reference. If arrays or other directional speaker technology are used, the signals may be provided to different combinations of speakers to provide some directional control. These arrays could be in the headrest or in other locations relatively close to the listener including locations in front of the listener.

Combinations of speakers can be used, with appropriate signal processing, to expand the spaciousness of the sound perceived by the user(s), and more precisely control the frontal sound stage. Different effects may be desired for different components of the audio signals-center signals, for example, may be tightly focused, while surround signals may be intentionally diffuse. In addition to differences due to the distance between each speaker and each ear, what each ear hears from each speaker will vary due to the angle at which the signals arrive and the anatomy of the listener's outer ear structures (which may not be the same for their left and right ears). Human perception of the direction and distance of sound sources is based on a combination of arrival time differences between the ears, signal level differences between the ears, and the particular effect that the user's anatomy has on sound waves entering the ears from different directions, all of which is also frequency-dependent. We refer to the combination of these factors at both ears, for a source at a given location, as the binaural response for that location. Binaural signal filters are used to shape sound that will be reproduced at a speaker at one location to sound like it originated at another location.

One aspect of the audio experience that is controlled by the tuning of the car is the sound stage. "Sound stage" refers to the listener's perception of where the sound is coming from. In particular, it is generally desired that a sound stage be wide (sound comes from both sides of the listener), deep (sound comes from both near and far), and precise (the listener can identify where a particular sound appears to be coming from). In an ideal system, someone listening to recorded music can close their eyes, imagine that they are at a live performance, and point out where each musician is located. A related concept is "envelopment," by which we refer to the perception that sound is coming from all directions, including from behind the listener, independently of whether the sound is precisely localizable. Perception of sound stage and envelopment (and sound location generally) is based on level and arrival-time (phase) differences between sounds arriving at both of a listener's ears, and the sound stage can be controlled by manipulating the audio signals produced by the speakers to control these inter-aural level and time differences. As described in <CIT>, various speakers in a car audio system may be used cooperatively to control spatial perception.

In some examples, the audio source provides only two channels, i.e., left and right stereo audio. Two other common options are four channels, i.e., left and right for both front and rear, and five channels for surround sound sources (usually with a sixth "point one" channel for low-frequency effects). Four channels are normally found when a standard automotive head unit is used, in which case the two front and two rear channels will usually have the same content, but may be at different levels due to "fader" settings in the head unit. To properly mix sounds for a system as described herein, the two or more channels of input audio are up-mixed into an intermediate number of components corresponding to different directions from which the sound may appear to come, and then re-mixed into output channels meant for each specific speaker in the system. One example of such up-mixing and re-mixing is described in <CIT>.

Component signals up-mixed from the source material can each be distributed to different phantom center image locations for rendering by the audio system <NUM>. As described herein, the audio system <NUM> can permit user control of the phantom center image locations (e.g., the perceived location of the phantom center image of the audio output), which in various implementations, can be controlled via the interface <NUM> (<FIG>). As explained with regard to <FIG>, the various fixed speakers <NUM>, <NUM>, <NUM>, <NUM> can be used to make sound seem to be coming from phantom speakers at different locations. The actual number of phantom center image locations may depend on the processing power of the system used to generate them, or the acoustic needs of the system. Although phantom center image locations (or, phantom speakers) are shown in <FIG> with respect to different listener locations as a number of phantom center image locations in front of each listener, the phantom center image locations may be distributed in height as well as left, right, front, and back. It is further understood that the arrays of phantom speakers in <FIG> are illustrative of only some of the phantom speaker configurations possible for each listener. Each individual listener in the automobile can have control over his/her own phantom speaker location for audio playback, or a centralized control for all users can be provided.

A given up-mixed component signal may be distributed to any one or more of the phantom speakers, which not only allows repositioning of the component signal's perceived location, but also provides the ability to render a given component as either a tightly focused sound, from one of the phantom speakers, or as a diffuse sound, coming from several of the phantom speakers simultaneously. To achieve these effects, a portion of each component is mixed into each output channel (though that portion may be zero for some component-output channel combinations). For example, the audio signal for a right component will be mostly distributed to the right fixed front speaker <NUM>, but to position each phantom speaker on the right side of the head <NUM>, portions of the right component signal are also distributed to the right rear speaker <NUM> and the left rear speaker <NUM>, due to both the target binaural response of the phantom speaker. The audio signal for the center component will be distributed to the corresponding right and left fixed speakers <NUM> and <NUM>, with some portion also distributed to both the right and left rear speakers <NUM> and <NUM>, controlling the location from which the listener perceives the phantom center image to originate. The particular distribution of component content to the output channels will vary based on how many and which speakers are installed.

<FIG> illustrates example perceived phantom center image locations <NUM>, <NUM> and <NUM> for a user (listener) sitting in the driver's seat of the automobile. <FIG> shows example perceived phantom center image locations <NUM>, <NUM> and <NUM> for a user (listener) sitting in the passenger's seat of the automobile. <FIG> shows example perceived phantom center image locations <NUM>, <NUM>, and <NUM> for a user (similar to a user in <FIG>) sitting in the rear left seat of the automobile. <FIG> shows example perceived phantom center image locations <NUM>, <NUM>, and <NUM> for a user (similar to a user in <FIG>) sitting in the rear right seat of the automobile. These phantom center image locations for each user seating location are merely example locations adjustable by the user, e.g., via interface <NUM> (<FIG> and <FIG>, illustrated in <FIG> in simplified form for clarity of other illustrations). It is understood that in various implementations one or more interfaces similar to interface <NUM> can be located in the rear seat area of the vehicle, e.g., in a center console, on or proximate rear doors, or on the rear-facing surfaces of the front seats of the automobile. These additional interfaces <NUM> are illustrated in <FIG> and <FIG> on the rear-facing surfaces of the front seats of the automobile merely for illustrative purposes.

The term, "component" can refer to each of the intermediate directional assignments to which the original source material is up-mixed. In various implementations described herein, a stereo signal is up-mixed into an arbitrary number of component signals. In one example, there may be a total of five: front and surround for each of left and right, plus a center component. In such an example, the main left and right components may be derived from signals which are found only in the corresponding original left or right stereo signals. The center components may be made up of signals that are correlated in both the left and right stereo signals, and in-phase with each other. The surround components may be correlated but out of phase between the left and right stereo signals. Any number of up-mixed components may be possible, depending on the processing power used and the content of the source material. Various algorithms can be used to up-mix two or more signals into any number of component signals. One example of such up-mixing is described in <CIT>. Another example is the Pro Logic Ilz algorithm, from Dolby®, which separates an input audio stream into as many as nine components, including height channels. In general, components can be treated as being associated with left, right, or center. Left components are preferably associated with the left side of the vehicle, but may be located front, back, high, or low. Similarly, right components are preferably associated with the right side of the vehicle, and may be located front, back, high, or low. Center components are preferably associated with the centerline of the vehicle, but may also be located front, back, high, or low. Additional descriptions of up-mixing components can be found in <CIT>.

In certain implementations, there may not be a (discrete) center component, but one can be created by upmixing a stereo signal. Filters may be used to convert weighted sums of up-mixed component signals into a signal corresponding to sound coming from the perceived phantom center image locations (e.g., locations <NUM>, <NUM>, <NUM> in <FIG> or locations <NUM>, <NUM><NUM> in <FIG>). While each of the filters can receive all of the component signals, in practice, each phantom center image location may reproduce sounds from only a subset of the component signals, such as those signals associated with the corresponding side of the vehicle. As with the component signals, a phantom center image signal may actually be a combination of left and right phantom images. Various topologies of signal re-mixing are possible, and may be selected based on the processing capabilities of the system used to implement the filters, or on the processes used to define the tuning of the vehicle, for example.

With continuing reference to <FIG>, in contrast to conventional automobile audio systems, the audio system <NUM> can provide user-selectable modifications to the spatial placement of the audio output. In some particular implementations, the audio system <NUM> permits selection of a perceived phantom center image location of audio output across a range of pre-defined locations (e.g., phantom speaker locations, as described herein). As noted herein, the phantom center image of the audio output is a designated position of sound produced by a set of speakers (e.g., one or more of speakers <NUM>, <NUM>, <NUM>, <NUM>) in the audio system <NUM> other than physical locations of those speakers in the automobile. In one example, the phantom center image of an audio output of a song (e.g., a studio recording or live concert) is designated as the perceived location of the lead vocalist in a band, or the soloist in an orchestra. While some users may prefer a spatial placement such that the lead singer appears to be located directly ahead (e.g., approximately straight in front of the user), others may prefer a spatial placement such that the band is accurately spaced across the soundstage (e.g., such as they may be spaced on a physical stage). These preferences can lead to distinct spatial placement of the perceived phantom center image, e.g., a vocalist appearing to sing from directly in front of the driver versus from a center of the dashboard, or a center of the vehicle (e.g., at a mid-car location). That is, the audio system <NUM> permits one or more users to vary the sound presentation across a range between a symmetric stage with a center image mid-car, and an asymmetric stage with a center image directly in front of the user(s).

Employing audio system <NUM>, the user can actuate a control value command through the interface <NUM> (<FIG>) for shifting the perceived location of the phantom center image of the audio output. In response to that control value command, the control system <NUM> can apply/modify a filter on at least one of the speakers <NUM>, <NUM>, <NUM>, <NUM> (e.g., via source/processing/amplifying unit <NUM>) to adjust the perceived location of the phantom center image, providing an updated phantom center image of the audio output as perceived by the listener.

In adjusting the perceived location of the phantom center image of the audio output, it is understood that the audio system <NUM> maintains an approximately static left channel output and an approximately static right channel output. This sound produced by speakers <NUM>, <NUM>, <NUM>, <NUM> is detectable by the user, and includes an inter-aural phase and inter-aural level as perceived by the user that is consistent with a source from the designated position. This differentiates audio system <NUM> from conventional systems which perform balance control by moving the entire sound stage in response to a user command (e.g., by turning a balance dial). That is, audio system <NUM> is configured to adjust the perceived location of the phantom center image with no more than nominal movement of the left channel output and the right channel output. The scale of this nominal (or less than nominal movement) is determined by the number of speakers (and degrees of freedom) in the audio system <NUM>. This is in contrast to a conventional balance adjustment, which changes the center placement of the audio output through a maximum perceptual change of the left or right channel output, whereby the change to the center output is affected only through gain changes in the left channel output or right channel output.

As described herein, the spatial placement of the perceived phantom center image can be adjusted in various ways according to implementations. In some cases, the control system <NUM> is configured to adjust the perceived location of the phantom center image by adjusting one or more of: a) a center image azimuth angle of the audio output, b) a center image distance of the audio output, or c) a center image elevation of the audio output. The phantom center image azimuth angle can be adjusted by modifying a filter weight on at least one of the speakers <NUM>, <NUM>, <NUM>, <NUM> to adjust the angle at which the phantom center image appears relative to the user. The azimuth angle adjusts the angle at which the phantom center image is located relative to a user along a horizontal plane. The phantom center image distance can be adjusted, similarly by modifying a filter weight on at least one of the speakers <NUM>, <NUM>, <NUM>, <NUM>, to adjust the relative distance (closer or farther) at which the phantom center image appears with respect to the user. This distance adjustment moves the phantom center image closer to the user or farther from the user along a line at the same azimuth angle with respect to the user. The phantom center image elevation can be adjusted, similarly by modifying a filter weight on at least one of the speakers <NUM>, <NUM>, <NUM>, <NUM>, to adjust the relative elevation (higher or lower) at which the phantom center image appears with respect to the user. Elevation adjustment moves the phantom center image along a vertical axis that is perpendicular to the horizontal plane. In various particular implementations, the azimuth angle, distance and/or elevation can be modified using one or more speaker filter adjustments. In this sense, audio system <NUM> is configured to make three-dimensional adjustments to the perceived phantom center image location (along with other audio spatial placements described herein).

In some implementations, the phantom center image of the audio output is initially set to a default designated position. For example, the phantom center image of the audio output can be defined by default settings of the automobile, such as factory settings, and may place the phantom center image at the mid-car location (e.g., centered over the dashboard, such as where interface <NUM> is located in <FIG>). However, in particular implementations, the default designated position can be defined by a user (e.g., via a user profile command) or according to a characteristic of the automobile. For example, a user can designate phantom center image location(s) and save that location data as a profile command in a profile or other in other automobile settings (e.g., via pre-set actuatable interface buttons). The profile can be connected with one or more additional user-defined settings (e.g., seat position, volume, temperature control), or may be accessible by an identification mechanism (e.g., via an identification file) such as a particular key fob identification, smart device identification, visual or auditory personal identification, etc. attributed to the user. Settings for multiple users can also be saved and/or retrieved by control system <NUM> to tailor the location(s) of the phantom center image in the automobile.

As described herein, in particular implementations, the perceived location of the phantom center image is adjustable across a range of pre-defined angles (e.g., azimuth angles), elevations and/or distances. In these cases, the audio system <NUM> matches the user interface command to a nearest one of the pre-defined angles, elevations and/or distances to provide the adjusted perceived location of the phantom center image. In particular implementations, the perceived location of the phantom center image is adjustable between two or more settings for each of the seating positions in the vehicle. In more specific cases, <NUM>-<NUM> settings are available for selection by the user. However, in still further implementations, five or more settings are available for selection by the user. The number of settings can be limited in some cases by the available storage of filters in the control system <NUM> (and associated storage device). In some cases, an even greater of settings can be available, e.g., using interpolation.

In some additional implementations, the location(s) of the phantom center image is user-adjustable and not necessarily predefined, such that the source/processing/amplifying unit <NUM> calculates and implements filter modifications in real-time or near real-time. In some cases, this real-time or near real-time calculation is performed by an algorithm stored in the source/processing/amplifying unit <NUM>, and may interpolate between one or more fixed settings (e.g., as between locations Ni-Nn in Table I, included herein), or calculate a location of the phantom center image independently of the fixed settings.

As noted herein, in other particular implementations, the audio system <NUM> permits individualized selection of the perceived location of the phantom center image of the audio output. In these implementations, the interface command includes a plurality of commands from distinct interface controls (e.g., a plurality of interfaces <NUM>, as illustrated in <FIG>) to modify a plurality of phantom center images of the audio output, each relative to distinct seating locations. In these examples, each user is capable of individually adjusting the perceived phantom center image of audio output for their relative seating location (as described herein, based upon the expected binaural characteristics of the user's head at the seating location).

In additional implementations, a single (or global) interface can be used to permit all users to adjust one or more phantom center image locations. For example, interface <NUM> can be located in a center console of the vehicle and permit users at each of the seating locations to adjust their respective perceived phantom center image of audio output. This global interface can take the form of any other interface <NUM> shown or described herein. In still other implementations, the global interface can be accessible via one or more connected devices and/or smart devices. For example, a hard-wired or wireless controller can be coupled (e.g., physically or via a wireless communications protocol such as a Bluetooth protocol) to the control system <NUM> and allow user(s) to perform interface controls as described herein. Additionally, the control system <NUM> can be programmed to receive interface commands from a software application such as a mobile phone application or other smart device application. In these cases, one or more users can access a global control interface for perceived phantom center image locations relative to one or more seat locations using the software application on a connected device and/or smart device.

In some additional implementations, audio system <NUM> permits user(s) to adjust additional characteristics of the audio output, in addition to perceived phantom center image location. For example, in some implementations, control system <NUM> is configured to receive at least one additional interface command (e.g., via interface <NUM>) to modify at least one of: a) a left channel output, b) a right channel output, or c) content produced through up-mixing of an audio system signal or additional audio channels across the audio system <NUM>. Based upon this user interface command, the control system <NUM> is configured to adjust an additional spatial placement of the audio output.

<FIG> shows an example of an interface <NUM> for controlling the phantom center image placement of audio output from the audio system <NUM> according to various implementations. As shown, the interface <NUM> can include one or more interface command controls <NUM> for controlling aspects of the audio output as described herein. In some cases, interface command controls <NUM> can include a touch-screen, one or more actuatable buttons or knobs, a motion sensor, voice sensor (microphone) or any other interface control capable of receiving commands from a user. While in some cases the interface <NUM> is located in the automobile, such as an integrated interface within other audio control functions presented to the users, in other cases, the interface <NUM> can be accessible via a connected device such as a smart device, or via one or more voice, gesture and/or tactile commands. In the example shown in <FIG>, the command controls can include an actuatable knob (knob) <NUM> along with an actuatable slider (slider) <NUM>. It is understood that any interface command control <NUM>, such as the knob <NUM> and the slider <NUM> can be physical components (e.g., three-dimensional objects) or touch-screen displays representing such components. The interface command controls <NUM>, regardless of their display mechanism, can be actuatable to send control value commands to the control system <NUM> (FIG. <NUM>) to modify at least one filter (in the set of filters) on the audio output in order to adjust a perceived location of the phantom center image of the audio output. In some cases, a command control <NUM> such as knob <NUM> can enable three-dimensional adjustment of the phantom center image location (e.g., via multi-dimensional toggle, rotation and/or compression), however, in other cases, command controls <NUM> can combine to enable three-dimensional adjustment (e.g., where slider <NUM> controls azimuth and knob <NUM> controls distance and elevation).

In an additional example implementation shown in <FIG>, the interface <NUM> can include a touch screen <NUM> with an icon <NUM> that can be dragged in both the X and Y dimension (as well as diagonally between these axes) to adjust the azimuth or the elevation of the perceived location of the phantom center image for a user at a seating location. In some cases, the icon <NUM> can be be double-tapped, held, twisted (left or right) or otherwise manipulated to adjust the distance of the perceived location of the phantom center image from the user at the seating location.

According to the invention, the control system <NUM> includes programmable processor, programmed to apply/modify at least one filter on the audio output in response to receiving the control value command. The control system <NUM> is programmed to adjust the perceived location of the phantom center image across a range of pre-defined locations (e.g., locations <NUM>, <NUM>, <NUM> in <FIG> or locations <NUM>, <NUM>, <NUM> in <FIG>). In these implementations, the pre-defined locations and their associated speaker filters are stored in control system <NUM> or otherwise accessible by control system <NUM> (e.g., via a network interface or cloud-based communication system). These location/filter correlations can allow the control system <NUM> to provide real-time adjustment of the perceived location of the phantom center image in response to the control value command at interface <NUM>. Table I shows a simplified example correlation table for particular phantom center image locations with respect to one seating location (e.g., the location of any one of the users in <FIG>). As illustrated in Table I, the filter weights applied to the left channel and right channel remain the same across all locations of the perceived phantom center image (e.g., locations <NUM>, <NUM>, <NUM> in <FIG> or locations <NUM>, <NUM><NUM> in <FIG>). That is, the weights applied to the left channel output (left upmixing filter) and right channel output (right upmixing filter) remain the same regardless of the location of the perceived phantom center image. However, the weight applied to the center upmixing filter is varied across these locations (e.g., locations <NUM>, <NUM>, <NUM> in <FIG> or locations <NUM>, <NUM><NUM> in <FIG>). In this sense, the control system <NUM> is configured to apply a distinct weight to the center upmixing filter at each of the distinct phantom center image locations for each user (at a unique seating location).

In some additional implementations not falling under the scope of the claims, the weights applied to the left channel output (left upmixing filter) and right channel output (right upmixing filter) can be modified slightly across the center image locations, e.g., due to interaction between components, while the weight applied to the center upmixing filter is varied significantly. While the constant-weight configurations for the left upmixing filter and right upmixing filters are shown the Table I, it is understood that these weights may be modified slightly across the center image locations.

The weighting on the central upmixing filters can be used to control modification of one or more of azimuth angle, elevation and/or distance of the phantom center image relative to the user, while maintaining a substantially fixed right channel output and fixed left channel output.

In some implementations, Table I can be updated according to user feedback, e.g., as requested by control system <NUM>, in order to improve the response of the audio system <NUM> to user commands. As noted herein, in some implementations, the user can actuate command control(s) <NUM> or touch screen <NUM> which have pre-defined values correlated with locations along the array of phantom center image locations. In the example of a knob or a slide, the user can actuate the command control <NUM> (<FIG>) or touch screen <NUM> (<FIG>) to a specific value (e.g., in increments of X) that is directly correlated with a location (e.g., location <NUM>, <FIG>) and associated filter configuration (e.g., as in Table I). However, in other cases, the command control <NUM> (<FIG>) or touch screen <NUM> (<FIG>) permits the user to select values that are "between" adjacent locations (e.g., locations <NUM> and <NUM>, <FIG>), such that a pre-defined filter configuration is not necessarily saved for that location. In these scenarios, the control system <NUM> is configured to detect the control command value and choose a closest location to that value in order to select a corresponding weight (Wy) to apply to the filter configuration.

In still other implementations, as noted herein, the location(s) of the perceived phantom center image is not necessarily predefined, such that the control system <NUM> calculates and implements filter modifications in real-time or near real-time. In some cases, the control system <NUM> can include a machine learning engine, which may include an artificial neural network (ANN) or other artificial intelligence component configured to enhance the ability of audio system <NUM> to adjust the perceived location of the phantom center image in response to user commands. Additionally, the machine learning engine <NUM> can be used to update the stored location/filter correlations, e.g., in Table I in order to enhance the ability of audio system <NUM> to adjust the perceived location of the phantom center image in response to user commands.

The functionality described herein, or portions thereof, and its various modifications (hereinafter "the functions") can be implemented, at least in part, via a computer program product, e.g., a computer program tangibly embodied in an information carrier, such as one or more non-transitory machine-readable media, for execution by, or to control the operation of, one or more data processing apparatus, e.g., a programmable processor, a computer, multiple computers, and/or programmable logic components.

Actions associated with implementing all or part of the functions can be performed by one or more programmable processors executing one or more computer programs to perform the functions of the calibration process. All or part of the functions can be implemented as, special purpose logic circuitry, e.g., an FPGA and/or an ASIC (application-specific integrated circuit). Components of a computer include a processor for executing instructions and one or more memory devices for storing instructions and data.

Additionally, actions associated with implementing all or part of the functions described herein can be performed by one or more networked computing devices. Networked computing devices can be connected over a network, e.g., one or more wired and/or wireless networks such as a local area network (LAN), wide area network (WAN), personal area network (PAN), Internet-connected devices and/or networks and/or a cloud-based computing (e.g., cloud-based servers).

In various implementations, components described as being "coupled" to one another can be joined along one or more interfaces. In some implementations, these interfaces can include junctions between distinct components, and in other cases, these interfaces can include a solidly and/or integrally formed interconnection. That is, in some cases, components that are "coupled" to one another can be simultaneously formed to define a single continuous member. However, in other implementations, these coupled components can be formed as separate members and be subsequently joined through known processes (e.g., soldering, fastening, ultrasonic welding, bonding). In various implementations, electronic components described as being "coupled" can be linked via conventional hard-wired and/or wireless means such that these electronic components can communicate data with one another. Additionally, subcomponents within a given component can be considered to be linked via conventional pathways, which may not necessarily be illustrated.

Claim 1:
A computer-implemented method of controlling an audio system (<NUM>) with at least two inputs in an automobile, the two inputs respectively corresponding to a left and a right channel, the method comprising:
receiving at least one user interface command to modify a phantom center image of audio output from the audio system in the automobile,
wherein the phantom center image of the audio output comprises a designated position of sound produced by a set of speakers (<NUM>, <NUM>, <NUM>, <NUM>) in the audio system other than physical locations of the set of speakers in the audio system; and
adjusting a perceived location (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>) of the phantom center image of the audio output from the audio system based upon the at least one user interface command to modify the phantom center image of the audio output,
wherein the at least one user interface command comprises a plurality of commands from distinct user interface controls to modify a plurality of phantom center images of audio output, each relative to distinct seating locations, from the audio system in the automobile,
characterised in that the adjusting the perceived location comprises:
applying filter weights to the left channel output and the right channel output that remain the same regardless of the perceived location of the phantom center image of the plurality of phantom center images; and
applying a distinct filter weight to a center upmixing filter at each perceived location of the phantom center image of the plurality of phantom center images, wherein the upmixing filter is applied to an upmixed center component generated by upmixing the left and right channels