Patent Description:
The general problem in audio reproduction with loudspeakers is that usually reproduction is optimal only within one or a small range of listener positions, within the "sweet spot area".

This problem has been addressed by previous publications:
<CIT> discloses a method for detecting a plurality of available sound output devices when audio data is played back, and for detecting user position information and user direction information is provided. The method includes generating a plurality of pieces of sound information from the audio data, based on at least one of the detected user position information and the user direction information, and distributing each of the plurality of pieces of sound information to a corresponding sound output device from among the plurality of sound output devices.

<CIT> discloses an embodiment, in which an audio system may include a first set of speakers arranged in a first area, a second set of speakers arranged in a second area, an audio source for supplying sound signals to the speakers, and at least one detector for detecting the location of a user and for supplying a location signal to the audio source. The first area and the second area may be substantially non-overlapping. The audio source may be configured for controlling the sound signals to the speakers so as to produce a sound field having a position. The audio source may further be configured for adjusting, in response to the at least one location signal, the position of the sound field when a user moves from the first area to the second area. As a result, the position of the sound field may substantially coincide with the location of the user.

<CIT> discloses an audio processing apparatus with a receiver which receives audio data including audio components and render configuration data including audio transducer position data for a set of audio transducers. A renderer generating audio transducer signals for the set of audio transducers from the audio data. The renderer is capable of rendering audio components in accordance with a plurality of rendering modes. A render controller selects the rendering modes for the renderer from the plurality of rendering modes based on the audio transducer position data. The renderer can employ different rendering modes for different subsets of the set of audio transducers the render controller can independently select rendering modes for each of the different subsets of the set of audio transducers. The render controller can select the rendering mode for a first audio transducer of the set of audio transducers in response to a position of the first audio transducer relative to a predetermined position for the audio transducer. The approach may provide improved adaptation, e.g. to scenarios where most speakers are at desired positions whereas a subset deviate from the desired position(s).

Previous publications also include [<NUM>] by tracking a listener's position. The in [<NUM>] proposed systems aim at optimizing the perceived sound image in a specific user-dependent point, or within a certain area in which the listener is allowed to move.

Usually this area is bound by the layout of the loudspeaker setup, since as soon as a listener moves outside the loudspeaker setup, sound cannot be reproduced as intended anymore.

Another trend in sound reproduction are multi-room playback systems. With those, for example, one or multiple playback sources can be routed to different loudspeakers that are spread out over an area, e.g. in different rooms of a house.

Accordingly, there is a need for an audio signal processor for providing a plurality of loudspeaker signals, which provide a better tradeoff between complexity and the audio experience of a listener.

Embodiments according to the present invention are defined by the independent claims. Optional improvements are defined in the dependent claims. It should be noted, that any embodiments described herein, which do not comprise all features of one of the independent claims, or equivalents thereof, are for explanatory purposes and are helpful for understanding the invention.

An embodiment according to the invention is an audio signal processor for providing a plurality of loudspeaker signals, or loudspeaker feeds, on the basis of a plurality of input signals, like channel signals and/or object signals. The audio signal processor is configured to obtain an information about the position of a listener. The audio signal processor is further configured to obtain an information about the position of a plurality of loudspeakers, or sound transducers, which may, for example, be placed within the same containment, e.g. a soundbar. The audio signal processor is further configured to dynamically allocate loudspeakers for playing back the objects and/or channel objects and/or adapted signals, like adapted channel signals, derived from the input signals, like channel signals or channel objects. The adaptation of the location depends on the information about the position of the listener and on the information about the positions of the loudspeakers. For example, the audio signal processor can select a subset of loudspeakers for usage, in dependence on, for example, the distance between the listener and the loudspeakers. In other words, the audio signal processor decides which loudspeakers should be used in the rendering of the different channel objects or adapted signals. The audio signal processor is further configured to render the objects and/or the channel objects and/or the adapted signals derived from the input signals, in dependence on the information about the position of the listener, on the information about positions of the loudspeakers and in dependence on the allocation, in order to obtain the loudspeaker signals, such that a rendered sound follows a listener, when the listener moves or turns. The audio signal processor is further configured to identify loudspeakers dynamically in a predetermined environment of the listener, based on a distance between the listener and the loudspeaker. The audio signal processor is also configured to adapt a configuration of the input signals to the number of identified loudspeakers. Moreover, the audio signal processor is configured to dynamically allocate the identified loudspeakers for playing back the objects and/or channel objects and/or adapted signals, and to render objects and/or channel objects and/or adapted signals to loudspeaker signals of associated loudspeakers in dependence on position information of objects and/or channel objects and/or adapted signals and in dependence on the default loudspeaker position.

In other words, the audio signal processor uses knowledge about the position of loudspeakers and the position of the listener, or listeners, in order to optimize the audio reproduction and render the audio signals by using the already available loudspeakers. For example, one or more listeners can freely move within a room or an area in which different audio playback means, like passive loudspeakers, active loudspeakers, smartspeakers, soundbars, docking stations, television sets are located at different positions. The invented system facilitates that the listener can enjoy the audio playback as he/she would be in the center of the loudspeaker layout, given the current loudspeaker installment in the surrounding area.

In a preferred embodiment, the audio signal processor is configured to obtain an information about an orientation of the listener. The audio signal processor is further configured to dynamically allocate loudspeakers for playing back an object and/or a channel object and/or of adapted signals, like adapted channel signals, derived from the input signals, like channel signals or channel objects, or like upmixed or downmixed signals, in dependence on the information about the orientation of the listener. The audio signal processor is further configured to render the objects and/or the channel objects and/or the adapted signals derived from the input signals, in dependence on the information about the orientation of the listener, in order to obtain the loudspeaker signals, such that a rendered sound follows the orientation of the listener.

Rendering the objects and/or the channel objects and/or the adapted signals according to the orientation of the listener is, for example, a loudspeaker analogy of headphone behavior for a listener's head rotation. For example, the position of perceived sources stays fixed in relation to the listener's head orientation while the listener is rotating his view direction.

In a preferred embodiment, the audio signal processor is configured to obtain an information about an orientation and/or about an acoustical characteristic and/or about a specification of the loudspeakers. The audio signal processor is further configured to dynamically allocate loudspeakers for playing back the objects and/or channel objects and/or of adapted signals, like adapted channel signals, derived from the input signals, like channel signals or channel objects, or like upmixed or downmixed signals, in dependence on the information about an orientation and/or about a characteristic and/or about a specification of the loudspeakers. The audio signal processor is further configured to render the object and/or the channel objects and/or the adapted signals derived from the input signals, in dependence on the information about an orientation and/or about a characteristic and/or about specification of the loudspeakers, in order to obtain the loudspeaker signals such that the rendered sound follows the listener and/or the orientation of the listener when the listener moves or turns. An example for the characteristic of the loudspeaker can be information, whether the loudspeaker is part of a speaker array or not, or whether the loudspeaker is an array speaker or not, or whether the loudspeaker can be used for beamforming or not. A further example for the characteristics of the loudspeaker is its radiation behavior, e.g. how much energy it radiates into different directions for different frequencies.

Obtaining information about an orientation and/or about characteristics and/or about a specification of the loudspeakers can improve the listener's experience. For example, the allocation can be improved by choosing the loudspeakers with the correct orientation and characteristics. Or, for example, the rendering can be improved by correcting the signal according to the orientation and/or the characteristics and/or the specification of the loudspeakers.

In a preferred embodiment, the audio signal processor is configured to smoothly and/or dynamically change an allocation of loudspeakers for playing back an object, or of a channel object, or of adapted signals, like adapted channel signals, derived from the input signals, like channel signals or channel objects, or like upmixed or downmixed signals, from a first situation to a second situation. In the first situation the objects and/or channel objects and/or adapted signals of an input signal are allocated to a first loudspeaker setup, like for example <NUM>, corresponding to a channel-based input signal, and/or the channel configuration, like for example <NUM>, of the input signal. In other words, in the first situation, there is a one-to-one allocation of channel objects to loudspeakers. In the second situation the objects and/or channel objects and/or the adapted signals of the channel-based input signal are allocated to a true subset of the loudspeakers of the first loudspeaker setup and to at least one additional loudspeaker, which does not belong to the first loudspeaker setup.

In other words, the listener's experience could be improved, for example by allocating the nearest subset of the loudspeakers of a given setup and at least one additional loudspeaker which happens to be nearby, or closer than other loudspeakers of the loudspeaker setup. Accordingly, it is not necessary to render an input signal which has a given channel configuration to a set of loudspeakers having a fixed association to that channel configuration.

In a preferred embodiment, the audio signal processor is configured to smoothly and/or dynamically allocate loudspeakers of a first loudspeaker setup for playing back the objects and/or of channel objects and/or of adapted signals, like adapted channel signals, derived from the input signals, like channel signals or channel objects, or like upmixed or downmixed signals, from a first situation to a second situation. In the first situation the objects and/or channel objects and/or the adapted signals of an input signal are allocated to a first loudspeaker setup, like <NUM>, corresponding to the channel configuration, like <NUM>, of the a channel-based input signal with a first loudspeaker layout. In other words, for example, in the first situation there is a one-to-one allocation of channel objects to loudspeakers with a first loudspeaker layout. In the second situation the objects and/or channel objects and/or the adapted signals of the input signal are allocated to a second loudspeaker setup, like <NUM>, which corresponds to a channel-based channel configuration, like <NUM>, of the input signal with a second loudspeaker layout. In other words, in the second situation there is a one-to-one allocation of channel objects to loudspeakers with a second loudspeaker layout.

The experience of the listener can be improved by adapting the allocation and rendering between two loudspeaker setups with different loudspeaker layouts. For example, the listener moves from a first loudspeaker setup with a first loudspeaker layout, where the listener is oriented towards the center loudspeaker, to a second loudspeaker setup with a loudspeaker layout, where, for example, the listener is oriented towards one of the rear loudspeakers. In this exemplary case, the orientation of the sound field follows the listener, wherein the allocation of channels of the input signal to loudspeakers may deviate from a standard or a "natural" allocation.

In a preferred embodiment, the audio signal processor is configured to smoothly and/or dynamically allocate loudspeakers of a first loudspeaker setup for playing back the objects and/or channel objects and/or adapted signals, like adapted channel signals, derived from the input signals, like channel signals or channel objects, or like upmixed or downmixed signals, according to a first allocation scheme, in agreement with the first loudspeaker layout. The audio signal processor is further configured to smoothly and/or dynamically allocate loudspeakers of a second loudspeaker setup for playing back the allocate objects and/or channel objects and/or adapted signals derived from the input signals, according to a second allocation scheme, which differs from the first allocation scheme, in agreement with a second loudspeaker layout. In other words, the audio signal processor is capable of smoothly allocating objects and/or channel objects and/or adapted signals between, for example, different loudspeaker setups with different loudspeaker layouts. As, for example, the listener moves from the first loudspeaker setup to the second loudspeaker setup, the audio image follows the listener. The audio signal processor is configured to, for example, allocate objects and/or channel objects and/or adapted signals, even if the loudspeaker setups are different (e.g. comprise a different number of loudspeakers), for example the first loudspeaker setup is <NUM> audio system, and the second loudspeaker setup is a stereo system.

In a preferred embodiment, the loudspeaker setup corresponds to a channel configuration, like <NUM>, of the input signals. The audio signal processor is configured to dynamically allocate loudspeakers of the loudspeaker setup for playing back the objects and/or channel objects and/or adapted signals, such that the allocation deviates from the correspondence, in response to a difference between the listener's position and/or orientation from a default, or standard, listener's position and/or orientation associated with the loudspeaker setup.

In other words, for example, the audio signal processor can change the orientation of the sound image, such that the channel objects are not allocated to those loudspeakers to which they would be allocated normally in accordance with the default or standardized correspondence between channel signals and loudspeakers, but to different loudspeakers. For example, if the orientation of the listener is different from the orientation of the loudspeaker layout of the loudspeaker setup, the audio signal processor can, for example, allocate the objects and/or channel objects and/or adapted signals to loudspeakers of the loudspeaker setup, in order to, for example, correct the orientation difference between the listener and the loudspeaker layout, thus resulting in a better audio experience of the listener.

In a preferred embodiment, the first loudspeaker setup corresponds to a channel configuration, like <NUM>, according to a first correspondence. The audio signal processor is configured to dynamically allocate loudspeakers of the first loudspeaker setup for playing back the objects and/or channel objects and/or adapted signals according to this first correspondence. That means, for example, a default or standardized allocation of audio signals or channels complying with a given audio format, like <NUM> audio format, to loudspeakers of a loudspeaker setup complying with the given audio format. The second loudspeaker setup corresponds to a channel configuration according to a second correspondence. The audio signal processor is configured to dynamically allocate loudspeakers of the second loudspeaker setup for playing back the objects and/or channel objects and/or adapted signals, such that the allocation to loudspeakers deviates from this second correspondence.

In other words, for example, the audio signal processor is configured to keep the orientation of the sound image between loudspeaker setups, even if the orientation of the loudspeaker setups or loudspeaker layouts are different from each other. If, for example, the listener moves from a first loudspeaker setup, where the listener is oriented towards the center loudspeaker, to a second loudspeaker layout, where the listener is oriented towards a rear loudspeaker, the audio signal processor adapts the allocation of the objects and/or channel objects and/or adapted signals to the loudspeakers of the second loudspeaker setup, such that the orientation of the sound image remains.

In a preferred embodiment, the audio signal processor is configured to dynamically allocate a subset of all the loudspeakers of all the loudspeaker setups for playing back the objects and/or channel objects and/or adapted signals, like adapted channel signals, derived from the input signals, like channel signals or channel objects, or like upmixed or downmixed signals.

For some situations, it is advantageous that the audio signal processor is configured to, for example, allocate objects and/or channel objects and/or adapted signals to a subset of all the loudspeakers, based on, for example, the orientation of the loudspeakers or the distance between the loudspeakers and the listener, thus allowing, for example, an audio experience in areas between loudspeaker setups. For example, if a listener is between the first and the second loudspeaker setups, the audio signal processor can, for example, allocate only the rear loudspeakers of the two loudspeaker setups.

In a preferred embodiment the audio signal processor is configured to dynamically allocate a subset of all the loudspeakers of all the loudspeaker setups for playing back the objects and/or channel objects and/or adapted signals, like adapted channel signals, derived from the input signals, like channel signals or channel objects, or like upmixed or downmixed signals, such that the subset of the loudspeakers surround the listener.

In other words, for example, the audio signal processor is selecting a subset of all available loudspeakers, such that the listener is located between or amongst the selected loudspeakers. The selection of the loudspeakers can be based, for example, on the distance between the loudspeakers and the listener, on the orientation of the loudspeakers, and on the position of the loudspeakers. The audio experience of the listener is considered better if, for example, the listener is surrounded with the loudspeakers.

In a preferred embodiment, the audio signal processor is configured to render the objects and/or channel objects and/or adapted signals derived from the input signals, like channel signals or channel objects, or like upmixed or downmixed signals, with defined follow-up times, such that, the sound image follows the listener in a way, that rendering is adapted smoothly over time.

In a preferred embodiment, the audio signal processor is configured to identify loudspeakers in a predetermined environment of the listener. The audio signal processor is further configured to adapt a configuration, the number of signals available for the rendering, of the input signals, like channel signals and/or object signals, to the number of identified loudspeakers, that means adapting signals via upmix and/or downmix. The audio signal processor is further configured to dynamically allocate the identified loudspeakers for playing back the objects and/or channel objects and/or adapted signals. The audio signal processor is further configured to render objects and/or channel objects and/or adapted signals to loudspeaker signals of associated loudspeakers in dependence on position information of objects and/or channel objects and/or adapted signals and in dependence on the default or standardized loudspeaker position.

In other words, the audio signal processor selects loudspeakers according to a predetermined requirement, for example, based on the orientation of the loudspeaker and/or the distance between the listener and the loudspeaker. The audio signal processor adapts the number of channels to which the input signals are upmixed or downmixed (to obtain adapted signals) to the number of selected loudspeakers. The audio signal processor allocates the adapted signals to the loudspeakers, based on, for example, the orientation of the listener and/or the orientation of the loudspeaker. The audio signal processor renders the adapted signals to loudspeaker signals of allocated loudspeakers based on, for example, the default or standardized loudspeaker position and/or on the position information about the objects and/or channel objects and/or adapted signals.

The audio signal processor improves the listener's audio experience by, for example, choosing the loudspeakers around the listener, adapting the input signal to the chosen loudspeakers, allocating the adapted signals to the loudspeakers based on the orientation of the loudspeaker and the listener, and rendering the adapted signals based on the position information or the default loudspeaker position. Thus, for example, a situation can result where the listener, surrounded by different loudspeaker setups, is experiencing the same sound image while the listener is moving from one loudspeaker setup to another loudspeaker setup and/or moving between the loudspeaker setups, even if, for example, the loudspeaker setups are oriented differently and/or have a different number of channels.

In a preferred embodiment, the audio signal processor is configured to compute a position or an absolute position of the objects and/or channel objects on the basis of information about the position and/or the orientation of the listener. Calculating the positions of objects and/or channel objects improves the listener experience further by, for example, allocating the objects to the nearest loudspeaker with respect to, for example, the orientation of the listener.

According to an embodiment, the audio signal processor is configured to physically compensate the rendered objects and/or channel objects and/or adapted signals in dependence on the default loudspeaker position, on the actual loudspeaker position, and on the relationship between a sweet spot and the listener's position. The audio experience can be improved by, for example, adjusting the volume and the phase-shift of the loudspeakers, if, for example, the listener is not in a sweet spot of the default or standard loudspeaker setup.

According to a further embodiment, the audio signal processor is configured to dynamically allocate one or more loudspeakers for playing back the objects and/or channel objects and/or adapted signals, in dependence on the distances between the position of the objects and/or of the channel objects and/or of the adapted signals and the loudspeakers.

According to a further embodiment, the audio signal processor is configured to dynamically allocate one or more loudspeaker having a smallest distance or smallest distances from the absolute position of the objects and/or channel objects and/or adapted signals for playing back the objects and/or channel objects and/or adapted signals to. In an exemplary situation, the object and/or channel object can be positioned within a predefined range of one or more loudspeakers. In this example, the audio signal processor is able to allocate the object and/or channel object to all of this/these loudspeakers.

According to a further embodiment, the input signal has an ambisonics and/or higher order ambisonics and/or binaural format. The audio signal processor is able to handle, for example, audio formats which includes positional information as well.

According to further embodiments, the audio signal processor is configured to dynamically allocate loudspeakers for playing back the objects and/or channel objects and/or adapted signals, such that a sound image of the objects and/or channel objects and/or adapted signals follows a translational and/or orientation movement of the listener. Whether, for example, the listener is changing position and/or orientation, the sound image is following the listener.

In a further embodiment, the audio signal processor is configured to dynamically allocate loudspeakers for playing back the objects and/or channel objects and/or adapted signals, such that a sound image of the objects and/or channel objects and/or adapted signals follow a change of the listener's position and a change of a listener's orientation. In this rendering mode the audio signal processor is capable of, for example, imitating headphones, such that the sound objects are having the same position relative to the listener, even if the listener moves around.

According to a further embodiment, the audio signal processor is configured to dynamically allocate loudspeakers for playing back the objects and/or channel objects and/or adapted signals following a change of the listener's position, but remains stable against changes of the listener's orientation. This rendering mode can result in a sound experience, in which the sound objects in the sound field have a fixed direction but still follow the listener.

In a preferred embodiment, the audio signal processor is configured to dynamically allocate loudspeakers for playing back the objects and/or channel objects and/or adapted signals, in dependence on information about positions of two or more listeners, such that the sound image of the objects and/or channel objects and/or adapted signals is adapted depending on a movement or turn of two or more listener. For example, the listeners can move independently, such that, for example, a single sound image can be rendered to split up into two or more sound images, for example using different subsets of loudspeakers. If, for example, the first listener is moving towards the first loudspeaker setup and the second listener is moving towards the second loudspeaker setup starting from the same position, then, for example, both of them can be followed by the same sound image.

In a preferred embodiment, the audio signal processor is configured to track the position of the one or more listener in close to real time. Real-time or close to real-time tracking allows, for example, a faster speed for the listener, or a smoother movement of the sound image following the listener.

According to an embodiment, the audio signal processor is configured to fade the sound image between two or more loudspeaker setups in dependence on the positional coordinates of the listener, such that the actual fading ratio is dependent on the actual position of the listener or on the actual movement of the listener. For example, as a listener moves from the first loudspeaker setup to a second loudspeaker setup, the volume of the first loudspeaker setup lowers and the volume of the second loudspeaker setup increases, according to the position of the listener. If, for example, the listener stops, the volume of the first and second loudspeaker setups does not change further, as long as the listener remains in his/her position. A position-dependent fading allows for a smooth transition between the loudspeaker setups.

According to further embodiments, the audio signal processor is configured to fade the sound image from a first loudspeaker setup to a second loudspeaker setup, wherein a number of loudspeakers of the second loudspeaker setup is different from the number of loudspeakers of the first loudspeaker setup. In an exemplary situation, the sound image will follow the listener from a first loudspeaker setup to a second loudspeaker setup, even if the number of loudspeakers of the two loudspeaker setups are different. The audio signal processor can, for example, apply a panning, a downmix, or an upmix, in order to adapt the input signal to the different number of loudspeakers of the first and/or second loudspeaker setup.

Upmixing is not the only option for the adaptation of the input signal, for example, to a greater number of loudspeakers of the given loudspeaker setup. A simple panning can be also applied, which means, the same signal is played over two or more loudspeakers. In contrast, upmix means, at least in this document, that entirely new signals are generated potentially Fusing a sophisticated analysis and/or separating the components of the input signal.

Similarly to upmix, downmix means, that entirely new signals are generated, potentially using a sophisticated analysis and/or merging together the components of the input signal.

According to an embodiment, the audio signal processor is configured to adaptively upmix or downmix the objects and/or channel objects in dependence on the number of the objects and/or channel objects in the input signal and in dependence on the number of loudspeakers dynamically allocated to the objects and/or channel objects, in order to obtain adapted signals. For example, the listener moves from the first loudspeaker setup to the second loudspeaker setup and the number of loudspeakers in the loudspeaker setups are different. In this exemplary case, the audio signal processor adapts the number of channels to which the input signal is upmixed or downmixed, from the number of loudspeakers in the first loudspeaker setup to the number of loudspeakers in the second loudspeaker setup. Adaptively upmixing or downmixing the input signal results in a better listener's experience, in which, for example, the listener can experience all the channels and/or objects in the input signal, even if there are less or more loudspeakers available.

In a further embodiment, the audio signal processor is configured to smoothly transit the sound image from a first state to a second state. In the first state a full audio content is rendered to a first loudspeaker setup, while no signals are applied to a second loudspeaker setup. In the second state an ambient sound of the audio content, represented by the input signals, is rendered to the first loudspeaker setup, or to one or more loudspeakers of the first loudspeaker setup, while directional components of the audio content are rendered to the second loudspeaker setup. For example, the input signal may comprise ambience channels and direct channels. However it is also possible, to derive ambient sound (or ambient channels) and directional components (or direct channels) from the input signals using an upmix or using an ambience extraction. In an exemplary scenario, the listener is moving from the first loudspeaker setup to the second loudspeaker setup, while only the directional components, like a dialog of a movie, are following the listener. This rendering method allows the listener, for example, to focus more on the directional components of the audio content, as the listener moves from the first loudspeaker setup to the second loudspeaker setup.

According to further embodiments the audio signal processor is configured to smoothly transit the audio image from a first state to a second state. In the first state a full audio content is rendered to a first loudspeaker setup, while no signals are applied to a second loudspeaker setup. In the second state an ambient sound of the audio content, represented by the input signals, and directional components of the audio content are rendered to different loudspeakers in the second loudspeaker setup. For example, the input signal may comprise ambience channels and direct channels. However it is also possible, to derive ambient sound (or ambient channels) and directional components (or direct channels) from the input signals using an upmix or using an ambience extraction. In an exemplary scenario, the listener moves from a first loudspeaker setup to a second loudspeaker setup, where the number of loudspeakers in the second loudspeaker setup is, for example, higher than the number of loudspeakers in the first loudspeaker setup or the number of channels and/or objects in the input signal. In this exemplary case, all the channels and/or objects in the input signal could be allocated to a loudspeaker of the second loudspeaker setup and the remaining non-allocated loudspeakers of the second loudspeaker setup can, for example, play the ambient sound component of the audio content. As a result, the listener, for example, can be more surrounded with the ambient content.

In a preferred embodiment, the audio signal processor is configured to associate a position information to an audio channel of a channel-based audio content, in order to obtain a channel object, wherein the position information represents a position of a loudspeaker associated with the audio channel. For example, if the input signal contains audio channels without position information, the audio signal processor allocates position information to the audio channel in order to obtain a channel object. The position information can, for example, represent a position of a loudspeaker associated with the audio channel, thus creating channel objects from audio channels.

In a preferred embodiment, the audio signal processor is configured to dynamically allocate a given single loudspeaker for playing back the objects and/or channel objects and/or adapted signals, which is positioned closest to the listener, as long as a listener is within a predetermined distance range from the given single loudspeaker. In this rendering method, for example, the audio signal processor allocates the objects and/or channel objects and/or adapted signals to a single loudspeaker. For example, using a definable adjustment- and/or fading- and/or cross-fade-time, the objects and/or channel objects are reproduced using the loudspeaker closest to their position relative to the listener. In other words, for example, using a definable adjustment- and/or fading- and/or cross-fade-time, the objects and/or channel objects are reproduced by the loudspeaker closest to and within a predetermined distance from the listener's position.

In a preferred embodiment, the audio signal processor is configured to fade out a signal of the given single loudspeaker, in response to a detection that the listener leaves the predetermined range. If, for example, the listener is too far away from the loudspeaker, the audio signal processor fades out the loudspeaker, making for example the audio reproducing system more energy-efficient.

In a preferred embodiment, the audio signal processor is configured to decide, to which loudspeaker signals the objects and/or channel objects and/or adapted signals are rendered. The rendering depends on the distance of two loudspeakers, like adjacent loudspeakers, and/or depends on an angle between the two loudspeakers when seen from a listener's position. For example, the audio signal processor can decide between rendering an input signal pairwise to two loudspeakers or rendering the input signal to a single loudspeaker. This rendering method allows, for example, the sound image to follow a listener's orientation.

Further embodiments according to the invention create respective methods.

However, it should be noted that the methods are based on the same considerations as the corresponding audio signal processor. Moreover, the methods can be supplemented by any of the features, functionalities and details which are described herein with respect to the audio signal processor, both individually and taken in combination.

As a further general remark, it should be noted that the loudspeaker setups mentioned herein may optionally be overlapping. In other words, one or more loudspeakers of a "second loudspeaker setup" may optionally also be part of a "first loudspeaker setup". Alternatively, however, the "first loudspeaker setup" and the "second loudspeaker setup" may be separate and may not comprise any common loudspeakers.

Embodiments according to the present application will subsequently be described taking reference to the enclosed figures, in which:.

In the following, different inventive embodiments and aspects will be described. Also, further embodiments will be defined by the enclosed claims.

Moreover, features and functionalities disclosed herein relating to a method can also be used in an apparatus (configured to perform such functionality). Furthermore, any features and functionalities disclosed herein with respect to an apparatus can also be used in a corresponding method. In other words, the methods disclosed herein can be supplemented by any of the features and functionalities described with respect to the apparatuses.

The invention will be understood more fully from the detailed description given below and from the accompanying drawings of embodiments of the invention, which, however, should not be taken to limit the invention to the specific embodiments described, but are for explanation and understanding only.

<FIG> shows an audio system <NUM> and a listener <NUM>. The audio system <NUM> comprises an audio signal processor <NUM> and a plurality of loudspeaker setups 1420a-c. Each loudspeaker setup 1420a, 1420b, 1420c comprises one or more loudspeakers <NUM>. All the loudspeakers <NUM> of the loudspeaker setups 1420a, 1420b, 1420c are connected (directly or indirectly) to the output terminal of the audio signal processor <NUM>. Inputs of the audio signal processor <NUM> are the position of the listener <NUM>, position of the loudspeakers <NUM>, and an input signal <NUM>. The input signal <NUM> comprises audio objects <NUM> and/or channel objects <NUM> and/or adapted signals <NUM>.

The audio signal processor <NUM> is dynamically providing a plurality of loudspeaker signals <NUM> from the input signal <NUM>, such that a sound follows a listener. Based on the information about the position of a listener <NUM> and the information about the position of the loudspeakers <NUM>, the audio signal processor <NUM> dynamically allocates the objects <NUM> and/or the channel objects <NUM> and/or the adapted signals <NUM> of the input signal <NUM> to the loudspeakers <NUM>. As the listener <NUM> changes position the audio signal processor <NUM> adapts the allocation of the objects <NUM> and/or channel objects <NUM> and/or adapted signals <NUM> to different loudspeakers <NUM>. Based on the position of the listener <NUM> and the position of the loudspeakers <NUM> the audio signal processor <NUM> dynamically renders the audio objects <NUM> and/or channel objects <NUM> and/or adapted signals <NUM> in order to obtain the loudspeaker signals <NUM> such that the sound follows the listener <NUM>.

In other words, the audio signal processor <NUM> uses knowledge about the position of the loudspeakers <NUM> and the position of listener <NUM>, in order to optimize the audio reproduction and render the audio signal by advantageously using the available loudspeakers <NUM>. The listener <NUM> can freely move within a room or a large area in which different audio playback means, like passive loudspeakers, active loudspeakers, smartspeakers, sound bars, docking stations, TVs, are located at different positions. The listener <NUM> can enjoy the audio playback as he/she would be in the center of the loudspeaker layout, given the current loudspeaker installment in the surrounding area.

<FIG> shows a simplified block diagram <NUM> which comprises the main functions of the audio signal processor <NUM>, which may be similar to the audio signal processor <NUM> on <FIG>. Inputs of the audio signal processor <NUM> are the position of the listener <NUM>, the position of the loudspeakers <NUM> and the input signals <NUM>. The audio signal processor <NUM> has two main functions: the allocation of signals to loudspeakers <NUM>, which is followed by the rendering <NUM> or which may be combined with the rendering. Inputs of the signal allocation <NUM> are the input signals <NUM>, the position of the listener <NUM> and the position of the loudspeakers <NUM>. The output of the signal allocation <NUM> is connected to the rendering <NUM>. Further inputs of the rendering <NUM> are the position of the listener <NUM> and the position of the loudspeakers <NUM>. The output of the rendering <NUM>, which is the output of the audio signal processor <NUM> as well, are the loudspeaker signals <NUM>. The audio signal processor <NUM>, the position of the listener <NUM>, the position of the loudspeakers <NUM>, the input signals <NUM> and the loudspeaker signals <NUM> may be respectively similar to the audio signal processor <NUM>, to the position of the listener <NUM>, to the position of the loudspeakers <NUM>, to the input signal <NUM> and to the loudspeaker signals <NUM> on <FIG>.

Based on the position of the listener <NUM> and the position of the loudspeakers <NUM> the audio signal processor <NUM> allocates <NUM> the input signals <NUM> to the loudspeakers <NUM> on <FIG>. As a next step, the audio signal processor <NUM> renders <NUM> the input signals <NUM> based on the position of the listener <NUM> and the position of the loudspeakers <NUM>, resulting in the loudspeaker signals <NUM>.

<FIG> shows a more detailed block diagram <NUM> which comprises the functions of an audio signal processor <NUM>, which may be similar to the audio signal processor <NUM> on <FIG>. The block diagram <NUM> is similar to the simplified block diagram <NUM> but it is more detailed. Inputs of the audio signal processor <NUM> are the position of the listener <NUM>, the position of the loudspeakers <NUM> and the input signals <NUM>. Outputs of the audio signal processor <NUM> are the loudspeaker signals <NUM>. Functions of the audio signal processor <NUM> are computing or reading and/or extracting the object positions <NUM>, which is followed by identifying loudspeakers <NUM>, which is followed by upmixing and/or downmixing <NUM>, which is followed by allocating signals to loudspeakers <NUM>, which is followed by the rendering <NUM>, which is followed by a physical compensation <NUM>. Inputs of the function computing object positions <NUM> are the position of the listener <NUM>, position of the loudspeakers <NUM> and the input signals <NUM>. The output of this function is connected to the function identifying loudspeakers <NUM>. Inputs of the function identifying loudspeakers <NUM> are the position of the listener <NUM>, the position of the loudspeakers <NUM> and the computed object positions. The output of this function is connected to the function upmixing and/or downmixing <NUM>. This function takes no other input and its output is connected to the function allocating signals to loudspeakers <NUM>. The inputs of the function allocating signals to loudspeakers <NUM> are the position of the listener <NUM>, the position of the loudspeakers <NUM> and the upmixed/downmixed signals. The output of the function allocating signals to loudspeakers <NUM> is connected to the function rendering <NUM>. The inputs of the function rendering are the position of the listener <NUM>, the position of the loudspeakers <NUM> and the allocated signals. The output of the function rendering is connected to the function physical compensation <NUM>. The inputs of the function physical compensation <NUM> are the position of the listener <NUM>, the position of the loudspeakers <NUM> and the rendered signals. The output of the function physical compensation <NUM>, which is the output of the audio signal processor <NUM>, are the loudspeaker signals <NUM>.

The audio signal processor <NUM>, the position of the listener <NUM>, the position of the loudspeakers <NUM>, the input signals <NUM> and the loudspeaker signals <NUM> may be respectively similar to the audio signal processor <NUM>, to the position of the listener <NUM>, to the position of the loudspeakers <NUM>, to the input signal <NUM> and to the loudspeaker signals <NUM> on <FIG>.

The block diagram <NUM>, the audio signal processor <NUM>, the position of the listener <NUM>, the position of the loudspeakers <NUM>, the input signals <NUM>, the loudspeaker signals <NUM> and the functions signal allocation <NUM> and rendering <NUM> may be respectively similar to the block diagram <NUM>, to the audio signal processor <NUM>, to the position of the listener <NUM>, to the position of the loudspeakers <NUM>, to the input signal <NUM>, to the loudspeaker signals <NUM> and to the functions signal allocation <NUM> and rendering <NUM> on <FIG>.

As a first step the audio signal processor <NUM> computes the object positions <NUM> of the objects and/or channel objects of the input signals <NUM>. The position of the objects can be an absolute position and/or relative to the position of the listener <NUM> and/or relative to the position of the loudspeakers <NUM>. As a next step the audio signal processor <NUM> is identifying and selecting loudspeakers <NUM> within a predefined range from the position of the listener <NUM> and/or within a predefined range from the computed object positions. As a next step the audio signal processor <NUM> adapts the number of channels and/or number of objects in the input signals <NUM> to the number of loudspeakers selected. If the number of channels and/or number of objects in the input signal <NUM> differs from the number of selected loudspeakers, the audio signal processor <NUM> is upmixing and/or downmixing <NUM> the input signals <NUM>. As a next step the audio signal processor <NUM> allocates the adapted, upmixed and/or downmixed signals to the selected loudspeakers <NUM>, based on the position of the listener <NUM> and the position of the loudspeakers <NUM>. As a next step the audio signal processor <NUM> renders <NUM> the adapted and allocated signals in dependence on the position of the listener <NUM> and on the position of the loudspeakers <NUM>. As a next step, the audio signal processor <NUM> physically compensates the difference between a standard loudspeaker layout and the current loudspeaker layout, and/or the difference between the current position of the listener <NUM> and the sweet spot position of the standard and/or default loudspeaker layout. The physically compensated signals are the output signals of the audio signal processor <NUM> and are sent to the loudspeakers <NUM> in <FIG>, as loudspeaker signals <NUM>.

<FIG> shows a basic representation of the audio signal processor <NUM>, which may be similar to the audio signal processor <NUM> on <FIG>. The inputs of the audio signal processor <NUM> are the audio input or input signals <NUM>, information about the listener position and orientation <NUM>, information about the position and orientation of the loudspeakers <NUM>, and information about the radiation characteristics of the loudspeakers <NUM>. The output of the audio signal processor <NUM> is an audio output or loudspeaker signals <NUM>.

The audio signal processor <NUM> receives and processes audio input or input signals <NUM>, information about the position and/or orientation of the listener <NUM>, information about position and orientation of the loudspeakers <NUM> and information about the radiation characteristics of the loudspeakers <NUM> in order to create an audio output or loudspeaker signals <NUM>.

In other words <FIG> shows a basic implementation of an audio signal processor <NUM>. One or more audio channels are received (e.g. in the form of the audio input <NUM>), processed, and outputted. The processing is determined by the positioning and/or orientation of the listener <NUM> and by the position and/or orientation and characteristics of the loudspeaker <NUM>,<NUM>. The inventive system facilitates that the listener can enjoy the audio playback as he/she would be in the center of the loudspeaker layout, given the current loudspeaker installments in the surrounding area.

<FIG> shows a schematic representation of an audio reproduction system <NUM>, which may correspond to the audio reproduction system <NUM> on <FIG>, and a plurality of playback devices <NUM>. The audio reproduction system <NUM> comprises an audio signal processor <NUM>, which may be similar to the audio signal processor <NUM> on <FIG>, and a plurality of loudspeakers <NUM>. The plurality of loudspeakers <NUM> may comprise, for example a mono smart speaker <NUM> (which may, for example, become part of a setup) and/or a stereo system <NUM> (which may, for example, form a setup, and which may, for example become a part of a larger setup) and/or a soundbar <NUM> (which may, for example, become part of a setup and which may, for example comprise multiple loudspeaker drivers which are arranged in the soundbar). The plurality of loudspeakers <NUM> are connected to the output of the audio signal processor <NUM>. The input of the audio signal processor <NUM> is connected to a plurality of playback devices <NUM>. Additional inputs of the audio signal processor <NUM> are information about the listener's position and orientation <NUM> and information about loudspeaker position and orientation <NUM> and information about loudspeaker radiation characteristics <NUM>.

The audio reproduction system <NUM>, the audio signal processor <NUM>, the position of the listener <NUM>, the position of the loudspeakers <NUM>, the input signals <NUM>, the loudspeaker signals <NUM> and the loudspeakers <NUM> may be respectively similar to the audio reproduction system <NUM>, to the audio signal processor <NUM>, to the position of the listener <NUM>, to the position of the loudspeakers <NUM>, to the input signal <NUM>, to the loudspeaker signals <NUM> and to the loudspeakers <NUM> on <FIG>.

Different playback devices <NUM> are sending different input signals <NUM> to the audio signal processor <NUM>. The audio signal processor <NUM> based on the information about the listener's position and orientation <NUM> and on the information about the loudspeaker position and orientation <NUM> and on the information about loudspeaker radiation characteristics <NUM> selects a subset of loudspeakers <NUM>, adapts and allocates the input signals <NUM> to the selected loudspeakers <NUM> and renders the processed input signals <NUM> in dependence on the information about the position of the listener and on the position and orientation of the loudspeaker and on the radiation characteristics of the loudspeaker <NUM>, in order to produce the loudspeaker's feeds or loudspeaker signals <NUM>. The loudspeaker feeds or loudspeaker signals <NUM> are transmitted to the selected loudspeakers <NUM>, such that a sound follows a listener.

<FIG> shows technical details and example implementations of a proposed system. The inventive method adaptively selects a loudspeaker setup, e.g. a subset or group of loudspeakers <NUM>, from the set of all available loudspeakers <NUM>. The selected subsets are the currently active or addressed loudspeakers <NUM>. It depends on the listener's position <NUM> and the chosen user settings which loudspeakers <NUM> are selected to be part of the subset. The selected group of loudspeakers <NUM> is then the active reproduction setup. Additionally, different user selectable settings can be chosen to influence the paradigm that is followed during the rendering process. The audio signal processor needs to know (or should know) the position of the listener <NUM> in <FIG>. The listener position <NUM> can be tracked, for example, in real-time. For some embodiments, additionally the orientation, or look direction of the listener can be used for the adaptation of the rendering. The audio signal processor also needs to know (or should know) the position and orientation or setup of the loudspeakers. In this application or document, we do not cover the topic of how the information about the user's position and orientation is detected or signaled to the system. We also do not cover the topic of how the position and characteristics of the loudspeakers are signaled to the system. Many different methods are available to achieve that. The same applies for the position of walls, doors, etc. We assume, that this information is known to the system.

<FIG> further explains an upmix and/or downmix function, similar to <NUM> on <FIG>, of an audio signal processor similar to <NUM> on <FIG>. <FIG> shows a mixing matrix 800a which has an input signal 803a with x input channels and an output signal 807a with y output channels. The mixing matrix 800a calculates the output signal 807a with y channels from linear combinations of the x input channels of the input signal 803a, for example, by duplicating or combining one or more of the input channels. For example, the mixing matrix may be simple. For example, the mixing matrix may perform a simple re-use (or multiple-use) of a given signal, possibly selected with simple factors, such as, for example, constant/multiplicative volume factors or gain factors or loudness factors.

<FIG> shows a downmixing matrix 800b which converts an input signal 803b with m channels into an output signal 807b with n-channels, where m is higher than n. The downmixing matrix 800b uses active signal processing in order to reduce the number of channels from m to n.

<FIG> shows the upmix 800c use-case of a mixing matrix. In this case the mixing matrix is converting an input signal 803c with n-channels into an output signal 807c with m-channels, where m is higher than n. The upmixing matrix 800c uses active signal processing in order increase the number of channels from n to m.

The upmix 800c and/or the downmix 800b function of an audio signal processor offer(s) a solution in cases, when the channel number of the input audio signal is different from the number of chosen loudspeakers and when an active signal processing is used to convert the number of channels between the input audio signal and the number of chosen loudspeakers.

For example, downmix or upmix can be active and more complex signal processing processes when compared to the pure mixing matrix. Such as, for example using an analysis of one or more input signals and a time- and/or frequency-variable adjustment of gain factors.

<FIG> shows an exemplary use scenario <NUM> of an audio reproduction system similar to <NUM> on <FIG>. The use scenario <NUM> comprises two <NUM> loudspeaker setups: Setup_1, <NUM>, and Setup_2, <NUM>, driven by an audio signal processor similar to <NUM> on <FIG>. Setup_1, <NUM>, and Setup_2, <NUM>, can optionally be separated by a wall <NUM>, or other acoustic obstacles. Both Setup_1, <NUM>, and Setup_2, <NUM>, may have a default, or standard, loudspeaker layout. The loudspeaker layout of Setup_2, <NUM>, is rotated, for example, by <NUM>°, in comparison to Setup_1, <NUM>. Both loudspeakers setups, Setup_1, <NUM>, and Setup_2, <NUM>, have a sweet spot LP1, <NUM>, and LP2, <NUM>, respectively. <FIG> further shows a trajectory <NUM> of a listener moving from LP1, <NUM>, to LP2, <NUM>.

The loudspeaker setup Setup_1, <NUM>, corresponds, for example, to the channel configuration of the input signal. For example, in the beginning, the listener is at LP1, <NUM>, at the sweet spot of Setup_1, <NUM>. As the listener moves from LP1, <NUM>, to LP2, <NUM>, the audio signal processor described herein allocates and renders the input signals, as described in <FIG>, such that, the sound image and the orientation of the sound image follows the listener. That means, for example, the front and center channels of the loudspeaker setup Setup_1, <NUM>, (or of the input signal) are played by the rear loudspeakers of the loudspeaker setup Setup_2, <NUM>. And respectively, the rear loudspeaker channels of the loudspeaker setup Setup_1, <NUM>, (or of the input signal) is played by the front and center loudspeakers of the loudspeaker setup Setup_2, <NUM>, in order to keep the orientation of the sound image.

In other words, <FIG> shows a descriptive example, to illustrate the difference between the state-of-the-art, or conventional, zone switching system and the method according to the present invention. Setup_1, <NUM>, and Setup_2, <NUM>, both feature a <NUM>-channel surround loudspeaker setup. The difference is the orientation of the two setups. In traditional terms, the loudspeakers LSS1_L, LSS1_C, LSS1_R define the front, which is at the top in Setup_1, <NUM>, while in Setup_2, <NUM>, this traditional front (LSS2_L, LSS2_C, LSS2_R) is at the bottom. Usually, in traditional playback scenarios, the channels of a playback medium, like DVD, and of an attached amplifier are transmitted with a fixed mapping, for example according to ITU standards, which defines that e.g. the first output channel is attached to the left loudspeaker, the second channel to the right loudspeaker, and the third channel to the center loudspeaker, etc..

For example, a listener is changing position (or moving) from Setup_1, <NUM>, position LP1, <NUM>, to Setup_2, <NUM>, position LP2, <NUM>. A traditional, or conventional, on/off-multi-room system would simply switch between the two setups, whereas the loudspeakers would be associated with their associated channels of the medium/amplifier, thus, the front image of the reproduction would change to a different direction.

Using the inventive methods, the loudspeakers are not connected to the output of the playback device in a fixed manner. The processor uses the information about the position of the loudspeakers and the position of the user to produce a consistent audio playback. In the present example, in Setup_2, <NUM>, the channel content that has been produced by LSS1_L, LSS1_C and LSS1_R, would in the transition to Setup_2, <NUM>, be taken over by the LSS2_SR and LSS2_SL. Such, the traditional front-back distinction in the loudspeaker setup is withdrawn, and the rendering is defined by the actual circumstances.

For example, the audio signal processor described herein, may have no fixed channels. As the listener is moving from Setup_1, <NUM>, to Setup_2, <NUM>, the audio signal processor described above may constantly optimize the listening experience. An intermediate stage could be for example, that the audio signal processor provides loudspeaker signals only for the loudspeakers LSS1_L, LSS1_SL, LSS2_L, LSS2_SL, meaning the number of channels are reduced to four and they are not playing their conventional roles.

<FIG> shows an exemplary use scenario <NUM> of an audio reproduction system similar to <NUM> on <FIG>. The use scenario <NUM> comprises two loudspeaker setups, Setup <NUM>, <NUM>, and Setup <NUM>, <NUM>, driven by an audio signal processor similar to <NUM> on <FIG>. The loudspeaker setups are in different rooms, Room <NUM>, <NUM>, and Room <NUM>, <NUM>. The loudspeaker setups could be optionally separated by an acoustic obstacle, like a wall <NUM>. Both, Setup <NUM>, <NUM>, and Setup <NUM>, <NUM>, are a <NUM> stereo loudspeaker setup. Loudspeaker setup Setup <NUM>, <NUM>, has a standard <NUM> loudspeaker layout, comprises loudspeakers LSS1_1 and LSS1_2, with a sweet spot LP1. The loudspeaker setup Setup <NUM>, <NUM>, has a non-standard stereo loudspeaker layout, which comprises loudspeakers LSS2_1 and LSS2_2. <FIG> further shows two listener trajectories <NUM>, <NUM>. The first listener trajectory <NUM> is near to the sweet spot of Setup <NUM>, <NUM>, in which the listener moves from LP2_1 to LP2_2 to LP2_3 and back to LP2_1, within Room <NUM>, <NUM>. The second trajectory <NUM> goes from LP3_1 within Setup <NUM> to LP3_2 within Setup <NUM>, <NUM>.

For example, as the listener moves along the along the first trajectory <NUM> and/or the listener moves along the second trajectory <NUM>, the audio signal processor described herein allocates and renders the input signals, as described in <FIG>, such that, the sound image and the orientation of the sound image follows the listener.

In other words, <FIG> shows another example with two rooms <NUM>, <NUM> and/or two setups <NUM>, <NUM>. In Room_1 <NUM>, a traditional two-channel stereo system, with LSS1_1 and LSS1_2 loudspeakers, is arranged, such that, for standard, untracked, playback the listener can enjoy good performance in the chair positioned at the sweet spot, LP1. In the adjacent Room_2 <NUM>, which could be, for example, a corridor, two loudspeakers LSS2_1 and LSS2_2 are positioned in an arbitrary arrangement. In <FIG>, besides the sweet spot listening point LP1, two further possible listening scenarios are depicted. The first one is an example of a listener moving within Room_1 <NUM> from LP2_1 to LP2_2 and LP2_3. The second scenario shows a listener transitioning from position LP3_1 in Room_1 <NUM> to LP3_2 in Room_2 <NUM>.

For example, the audio signal processors described herein provide loudspeaker signals such that a sound image follows a listener when the listener is moving along the first trajectory <NUM> or along the second trajectory <NUM>.

<FIG> shows an exemplary use scenario <NUM> of an audio reproduction system similar to <NUM> on <FIG>. The use scenario <NUM> comprises three loudspeaker setups, driven by an audio signal processor similar to <NUM> on <FIG>. Setup <NUM>, <NUM>, is a <NUM> system, Setup <NUM>, <NUM>, and Setup <NUM>, <NUM>, are single loudspeakers. Setup <NUM>, <NUM>, and Setup <NUM>, <NUM>, are in the same room, while Setup <NUM>, <NUM>, is in a second room. Setup <NUM>, <NUM>, is optionally separated from Setup <NUM>, <NUM>, and Setup <NUM>, <NUM>, with a wall <NUM> or with other acoustic obstacles. <FIG> further shows a trajectory <NUM> of a listener, as the listener moves from LP2_1 from Setup <NUM>, <NUM>, to LP2_2 from Setup <NUM>, <NUM>, and to LP3_2 in Setup <NUM>, <NUM>. In this scenario, as the listener moves from Setup <NUM>, <NUM>, to Setup <NUM>, <NUM>, the audio signal processor described above is providing a downmixed version of the input signal to the loudspeakers LSS1_1 and LSS1_4 and LSS2_1. It is further possible that the loudspeakers LSS1_1 and LSS1_4 are playing an ambient version of the audio signal and the loudspeaker LSS2_1 is playing a directional content of the audio signal. As the listener moves further, from LP2_2 to LP3_2, the sound of the loudspeakers LSS1_1, LSS1_4 and LSS2_1 fades out and a downmixed version of the input signal is played by the loudspeaker LSS3_1.

Yet, another scenario is exemplified in <FIG>. Initially, a listener enjoys a <NUM> playback at LP1 using the surround sound loudspeaker setup comprising LSS1_1 to LSS1_5. After some time, the listener moves to LP2_2 to work in the kitchen for example. During this transition, LSS2_1 is starting to play a downmixed version of the signals that have previously been played by loudspeakers in Setup <NUM>, <NUM>. While the user is at position LP2_2, the system may, for example, according to the chosen preferred rendering settings, play either:.

If, for example, the listener further transitions into the adjacent room, Setup <NUM>, <NUM>, there is only a mono loudspeaker present in the room, then, for example, a mono downmix of the content will be played from loudspeaker LSS3_1 only.

The described system can also be used and adapted for multiple users. As an example, two people watch TV in Zone_1 or Setup <NUM>, <NUM>, one person goes to Zone_2 or Setup <NUM>, <NUM>, in order to get something from the kitchen.

A mono downmix follows this person, so that he/she does not miss anything from the program, while the other person stays in Zone_2 or Setup <NUM>, <NUM>, (or Setup <NUM>, <NUM>) and enjoys the full sound. Direct/ambience decomposition could be part of the system, to allow better adaptability to different circumstances, which can be, for example, a part of the upmix. As another example, only the speech content and/or another listener-selected part of the content and/or seected objects are following the listener.

For example, the audio signal processor may determine, in dependence on the listener's position, which loudspeakers should be used for the audio playback, and provide the loudspeakers signals using an adapted rendering.

Different approaches for a listener adaptive rendering of an audio signal processor, similar to <NUM> on <FIG>, can be distinguished. One is an approach, in which the reproduced auditory objects are intended to have a fixed position within a reproduction area.

<FIG> shows an exemplary rendering approach <NUM> of a functionality of a rendering similar to <NUM> in <FIG>. In this rendering approach <NUM> the positions of the audio objects are fixed. <FIG> shows a listener <NUM> and two sound objects S_1 and S_2.

<FIG> shows the initial situation, the listener <NUM> perceiving S_1 and S_2 at the given positions.

<FIG> shows that the rendering is rotation invariant, if the listener <NUM> changes his/her orientation, he/she perceives the sound objects at the same positions or at the same absolute position.

<FIG> shows that the rendering is translation-invariant, if the listener <NUM> changes her position, he/she perceives the sound objects S_1, S_2 at the same position or at the same absolute position.

In other words, the inventive method can follow different, sometimes user-selectable, rendering schemes. One approach is, in which reproduced auditory objects are intended to have a fixed position within a reproduction area. They should keep this position even if a listener <NUM> within this area rotates his/her head or moves out of the sweet spot. This is exemplarily depicted in <FIG>. Two perceived auditory objects, S_1 and S_2 are produced by a playback system. In this figure, S_1 and S_2 are not loudspeakers, physical sound sources, but phantom sources, perceived auditory objects, that are rendered using a loudspeaker system that is not displayed in this figure. The listener <NUM> perceives S_1 slightly to the left, and S_2 towards the right. The target of such an approach is to keep the spatial position of those sound objects, independent of the position or look-direction of the listener.

For example, the audio signal processor may consider the desire to reproduce the auditory objects at fixed absolute positions, when determining the audio object positions or when deciding which loudspeakers should be used.

<FIG> shows an exemplary rendering approach <NUM> of a functionality of a rendering similar to <NUM> in <FIG>. In cases where the sound image follows the listener <NUM>, two basic different approaches can be distinguished, both are depicted in <FIG> shows different rendering scenarios of an audio signal processor, similar to <NUM> on <FIG>, where a listener <NUM> is perceiving two sound objects or phantom sources, S_1 and S_2.

<FIG> is the initial situation. <FIG> shows a rotation variant rendering where the listener <NUM> is changing his/her orientation and the perceived sound objects keeping their relative position to the listener <NUM>. The perceived sound objects are rotating with the listener <NUM>.

<FIG> shows a rotation invariant rendering, where the listener <NUM> changes his/her orientation and the perceived positions (or absolute positions) of the sound objects, phantom sources S_1, S_2 remain.

<FIG> shows a translation variant rendering, where the listener <NUM> changes his/her position and the perceived audio objects, phantom sources S_1, S_2 are keeping the relative positions to the listener <NUM>. As the listener <NUM> changes position, the audio objects are following him/her.

In other words, <FIG> shows a listener <NUM> and two perceived auditory objects.

<FIG> shows a rotational variant system. In this case the position of perceived sources stays fixed in relation to the listener's <NUM> head orientation. This is the loudspeaker analogy of a headphone behavior for a listener's <NUM> head rotation. Please note that this default behavior of headphone reproduction is not a default behavior for loudspeaker rendering, but requires sophisticated rendering technology to be available on loudspeakers.

<FIG> shows a rotationally invariant approach, where the perceived sources keep a fixed absolute position when the listener <NUM> rotates to a different view direction, so the perceived direction changes relative to the listener's <NUM> orientation.

<FIG> shows an approach that is variant to translational changes of the listener <NUM>. This is the loudspeaker analogy of a headphone behavior for translational listener head movement. Please note that this default behavior of headphone reproduction is not the default behavior for loudspeaker rendering, but requires sophisticated rendering technology to be available on loudspeakers. The different approaches can be mixed and applied according to definable rules to achieve different overall rendering results when the sound follows a listener <NUM>. Hence, the users of such a system or audio signal processor can even adjust the actual rendering scheme to their preference and liking. A perception similar to a virtual headphone can also be targeted by rotating and optionally translating the rendered sound image according to the listener's <NUM> movement.

Different rendering scenarios of the audio signal processor described above is shown in <FIG>. The audio signal processor may render the sound image, for example, in a rotation variant or a rotation invariant way, considering the translational movements of the listener as well. The rendering used by the audio signal processor may be defined by the use-case (e.g. gaming, movie or music) and/or may be defined by the listener as well.

<FIG> shows an exemplary rendering approach <NUM> of a functionality of a rendering, similar to <NUM> in <FIG>, of an audio signal processor. The rendering approach <NUM> comprises a listener <NUM> and stationary sound objects S_1 and S_2 rendered by an audio signal processor similar to <NUM> on <FIG>.

<FIG> shows the initial situation with one listener <NUM> and two audio objects, phantom sources. <FIG> shows that the listener <NUM> has changed his/her position while the audio objects, phantom sources S_1 and S_2 are keeping their absolute position.

In a stationary object rendering mode, the objects are positioned, rendered to a specific absolute position with respect to some room coordinates. This fixed position of the objects does not change when the listener <NUM> is moving. The rendering has to be adapted in such a way, that the listener <NUM> always perceives the sound objects as their sound are coming from the same absolute position in the room.

For example, the audio signal processor may reproduce the auditory objects at fixed absolute positions, when determining the audio object positions or when deciding which loudspeakers should be used. In other words, the audio signal processor renders the audio objects in a way, that the perceived location of the audio objects remains nearly stationary, even if the listener changes his/her position.

<FIG> shows an exemplary rendering approach <NUM> of a functionality of a rendering similar to <NUM> in <FIG>. The rendering approach <NUM> comprises a listener <NUM> and two sound objects S_1 and S_2 rendered by an audio signal processor similar to <NUM> on <FIG>. In the rendering approach <NUM> the audio signal processor considers the translational and rotational movement of the listeners <NUM> as well.

<FIG> shows the initial situation with one listener <NUM> and two audio objects, S_1 and S_2.

<FIG> shows an exemplary situation, where the listener <NUM> changed his/her position. In this case, the two audio objects S_1 and S_2 are following a listener <NUM>, that means, the two audio objects are keeping their relative positions to the listener <NUM> the same.

<FIG> shows an example, where the listener <NUM> changes his/her orientation. The two audio objects S_1 and S_2 are keeping their relative positions from the listener <NUM> the same. That means, the audio objects are turning with the listener <NUM>.

In other words, in a "virtual headphone" rendering mode, the sound image moves according to the listener's <NUM> orientation, or rotation, and position, or translation. The sound image is fully incurred to the listener's <NUM> position and orientation, that means relative to the listener <NUM>, the position of objects, in contrast to the stationary object mode, changed their absolute position in the room depending on the listener's <NUM> movement. The reproduced audio objects are not stationary in relation to an absolute position in the room, but always stationary relative to the listener <NUM>. They follow the listener's <NUM> position, and optionally, also the listener's <NUM> orientation.

For example, the audio signal processor may reproduce the auditory objects at a fixed relative position to the listener, when determining the audio object positions or when deciding which loudspeakers should be used. In other words, the audio signal processor renders the audio objects in a way, that the audio objects are changing their positions and orientations with the listener.

<FIG> shows an exemplary rendering approach <NUM> of a functionality of a rendering similar to <NUM> in <FIG>. The rendering approach <NUM> comprises a listener <NUM> and two sound objects S_1 and S_2 rendered by an audio signal processor similar to <NUM> on <FIG>. In the rendering approach <NUM> the audio signal processor considers only the translational movement of the listeners <NUM>.

13a shows the initial situation with one listener <NUM> and two audio objects S_1 and S_2.

As the listener <NUM> changes her position, as <FIG> shows, the two audio objects S_1 and S_2 are following the listener <NUM>. That means the relative positions of the audio objects S_1 and S_2 from the listener's <NUM> position remain the same.

<FIG> shows that as the listener <NUM> changes his/her orientation, and the absolute position of the two audio objects S_1 and S_2 remains.

In other words, in the rendering mode "incurred primary direction", the sound image is rendered by the audio signal processor in such a way, that the sound image moves according to the listener's <NUM> position, translation, but is stable against changes in listener's <NUM> orientation, rotation.

<FIG> shows a detailed schematic representation of a sound reproduction system <NUM>, which may be similar to the sound reproduction system <NUM> from <FIG>. The sound reproduction system <NUM> comprises loudspeaker setups <NUM>, an audio signal processor <NUM>, similar to the audio signal processor <NUM> on <FIG>, and a channel to object converter <NUM>. The channel-based content <NUM> of the input signal <NUM> on <FIG> is connected to the channel-to-object converter <NUM>. An additional input of the channel-to-object converter <NUM> is an information about the loudspeaker positions and orientations in an ideal loudspeaker layout <NUM>. The channel-to-object converter <NUM> is connected to the audio signal processor <NUM>. Inputs of the audio signal processor <NUM> are the channel objects <NUM> created by the channel-to-object converter <NUM>, objects from object-based content <NUM>, the selected rendering mode <NUM>, selected by a listener over a user interface <NUM>, the position and orientation of the listener <NUM> collected by a user tracking device <NUM> and the position and orientation <NUM> and a radiation characteristic <NUM> of a loudspeaker and optionally other environmental characteristics <NUM> (like, for example, information about acoustic obstacles, or for example, information about the room accoustics). <FIG> shows two main functions of the audio signal processor <NUM>: the object rendering logic <NUM> followed by the physical compensation <NUM>. The output of the physical compensation <NUM>, which is the output of the audio signal processor <NUM>, are the loudspeaker feeds or loudspeaker signals <NUM> which are connected to the loudspeakers <NUM> of the loudspeaker setups <NUM>.

The channel-based content <NUM> is converted by the channel-to-object converter <NUM> to channel objects <NUM> on the basis of the information about the standard or ideal loudspeaker positions and (optionally) orientations <NUM> of the ideal loudspeaker setup. The channel objects <NUM> along with the objects, or object-based content <NUM>, are the audio input signals of the audio signal processor <NUM>. The object rendering logic <NUM> of the audio signal processor <NUM> renders the channel objects <NUM> and audio objects <NUM> based on the selected rendering mode <NUM>, the listener's position and (optionally) orientation <NUM>, the position and (optionally) orientation of the loudspeakers <NUM>, the characteristics of the loudspeakers <NUM> (optionally) and optionally other environmental characteristics <NUM>. The rendering mode <NUM> is optionally selected by a user interface <NUM>. The rendered channel objects and audio objects are physically compensated by the physical compensation mode <NUM> of the audio signal processor <NUM>. The physically compensated rendered signals are the loudspeaker feeds or loudspeaker signals <NUM>, which are the output of the audio signal processor <NUM>. The loudspeaker signals <NUM> are the inputs of the loudspeakers <NUM> of the loudspeaker setups <NUM>.

In other words, the channel-to-object converter <NUM> converts each channel signal intended for a particular loudspeaker <NUM> of a loudspeaker setup <NUM>, wherein the intended loudspeaker setup does not necessarily have to be part of the currently available loudspeaker setups in the actual playback situation, into an audio object <NUM>, that means to a waveform plus associated metadata on intended loudspeaker position and (optionally) orientation <NUM> using the knowledge of the ideally intended production loudspeaker position and orientation <NUM>, or to a channel object <NUM>. We could coin (or define) the term channel object here. A channel object <NUM> consists of (or comprises) the audio waveform signal of a specific channel and as metadata, the position of the accompanying loudspeaker <NUM> that has been selected for reproduction of this specific channel during production of the channel-based content <NUM>.

It should be noted, that the loudspeakers <NUM> shown in <FIG> represent (or illustrate) the actually available loudspeakers or loudspeaker setups. For example, an intended loudspeaker setup may comprise one or more of the actually available loudspeakers, wherein, for example, individual loudspeakers of one or more actually available loudspeaker setups may be included into an intended loudspeaker setup without using all of the loudspeakers of the respective available loudspeaker setups.

In other words, the intended loudspeaker setup may "pick out" loudspeakers from the actually available loudspeaker setups. For example, the loudspeaker setups <NUM> may (each) comprise a plurality of loudspeakers.

The next step after conversion is the rendering <NUM>. The renderer decides which loudspeaker setups <NUM> are involved in the playback, and/or in the active setups. The renderer <NUM> generates a suitable signal for each of these active setups, possibly including downmix, which could be all the way down to mono, or upmix. These signals represent how the original multi-channel sound can be played back best to a listener who would be located at the sweet spot, creating setup-adapted signals. These adapted signals are then allocated to the loudspeakers and converted into virtual loudspeaker objects, which are subsequently fed into the next stage.

The next stage is signal panning and rendering. This part renders the virtual loudspeaker object to the actual loudspeaker signals considering the apparent user position and optionally orientation <NUM>, the loudspeaker position and optionally orientation <NUM> and optionally a radiation characteristic <NUM>, as well as the rendering mode selected <NUM> by the listener, like the virtual headphone, or the absolute rendering modes.

In the end, the physical compensation layer <NUM> compensates the physical consequences of the listener not being in the sweet spot of the respective loudspeaker setup <NUM>, for example, changing the delay, and/or the gain, and/or compensating the radiation characteristics, based on the listener's position and optionally orientation <NUM> and on the real loudspeaker positions and optionally orientation <NUM> and (optionally) characteristics <NUM>. See also application [<NUM>] for underlying technology.

The output of the object rendering logic are channel signals or loudspeaker feeds <NUM>, for a reproduction setup <NUM>. This means that the signals are adjusted, rendered relative to a defined reference listener position with a defined forward direction.

The physical compensation <NUM> does the gain, and/or delay, and/or frequency adjustment relative to a defined listener position, possibly with a defined forward direction, such that the object rendering logic can assume the reproduction setup to consist of loudspeakers <NUM> that are equidistant from the defined reference listener position, like delay adjustment, equally loud, like gain adjustment, and facing the listener, like frequency response adjustment.

In other words, the physical compensation may, for example, compensate for a non-ideal placement of the loudspeakers and/or from a difference between the listener's position and a sweet spot, while the rendering may, for example, assume that the listener is at a sweet spot of a loudspeaker setup.

<FIG> shows an audio signal processor <NUM>, which may be similar to <NUM> on <FIG>. Inputs of the audio signal processor <NUM> are the object-based input signals, like audio objects <NUM> and channel objects <NUM>, the selected rendering mode <NUM>, the user or listener position and optionally orientation <NUM>, the position and optionally orientation of the loudspeaker <NUM>, optionally the radiation characteristics of the loudspeakers <NUM>, and optionally other environment characteristics <NUM>. The outputs of the audio signal processor <NUM> are loudspeaker signals <NUM>. The functions of the audio signal processor <NUM> are separated into two main categories, a logical category <NUM> and the rendering <NUM>. The logical functional category <NUM> comprises identifying and selecting loudspeakers <NUM>, which is followed by a suitable signal generation, e.g. upmix/downmix <NUM>, which is followed by a signal allocation <NUM>. These steps are performed on the basis of the selected rendering mode <NUM>, on the position and optionally orientation of the listener <NUM>, the position and optionally orientation of the loudspeakers <NUM>, optionally the radiation characteristics of the loudspeakers <NUM> and optionally other environment characteristics <NUM>. The rendering <NUM> is based on the listener's position and optionally orientation <NUM>, on the position and optionally orientation of the loudspeakers <NUM>, optionally the radiation characteristics of the loudspeakers <NUM> and optionally other environment characteristics <NUM>.

The object-based input signals, like channel objects <NUM> and audio objects <NUM> are fed into the audio signal processor <NUM>. Based on the selected rendering mode <NUM>, the listener position and optionally orientation <NUM>, the loudspeaker position and optionally orientation <NUM>, the optionally radiation characteristics of the loudspeakers <NUM>, possibly other environment characteristics <NUM> and the object-based input signals <NUM>,<NUM>, the audio signal processor identifies and selects the loudspeakers <NUM>, followed by a generation of suitable signals or upmix/downmix <NUM> followed by a signal allocation to loudspeakers <NUM>. As a next step the allocated signals are rendered to the loudspeakers <NUM>, in order to create loudspeaker signals <NUM>.

In other words, the reproduction of the sound field is intended to be based on the listener's actual position <NUM>, as a sound follows a listener. To this end, the channel objects created from the channel-based content are repositioned based on, or follow, the position, and possibly the orientation, of the listener or user. Based on the adapted, repositioned target positions of the channel object(s), the loudspeakers that are going to be used for the reproduction of this channel object are selected out of all available loudspeakers. Preferably, the loudspeakers that are closest to the target position of the channel object are selected. The channel object(s) can then be rendered, like using standard panning techniques, using the selected subset of all loudspeakers. If the content that is to be played back is already available in object-based form, the exact same procedure for selecting the subset of loudspeakers and rendering the content can be applied. In this case, the intended position information is already included in the object-based content.

It should be noted that any embodiments described herein can be used individually or in combination with any other described herein. The features, functionalities and details can optionally be introduced in any other embodiments disclosed herein.

A first further embodiment of an audio signal processor is presented, which adjusts a reproduction or a rendering of one or more audio signals, based on a listeners positioning and a loudspeaker positioning with the aim of achieving an optimized audio reproduction for at least one listener.

Embodiments of a first sub-embodiment group, which deals with a listening space, is presented below.

In a second further embodiment, which is based on the first further embodiment, a variable of loudspeakers can be positioned in different setups and/or in different zones and/or different rooms.

In a third further embodiment, which is based on the first further embodiment, different information about the loudspeakers is known. For example their specific characteristics and/or their orientation and/or their on axis direction and/or their positioning in a specific layout (e.g. two-channel stereo setup; <NUM> channel surround setup according to ITU recommendation, etc.).

In a fourth further embodiment, based on a preceding embodiment, the position of the loudspeakers are known inside the room and/or relative to the room boundaries and/or relative to objects (e.g. furniture, doors) in the room.

In a fifth further embodiment, based on a preceding embodiment, the reproduction system has information about the acoustic characteristics (e.g. absorption coefficient, reflection characteristics) of objects (walls, furniture, etc.) in the environment around the loudspeaker(s).

Embodiments of a second sub-embodiment group, which deals with rendering strategies, is presented below.

In a sixth further embodiment, based on a preceding embodiment, the sound is switched between different loudspeakers. Moreover, the sound can be faded and/or crossfaded between different loudspeakers.

In a seventh further embodiment, based on a preceding embodiment, the loudspeakers in the setup are not linked to specific channels of a reproduction medium (e.g. channel1=Left, channel2=Right), but the rendering generates individual loudspeakers signals based on information about the actual content and/or information about the actual reproduction setup.

In an 8th further embodiment, based on a preceding embodiment, the downmix or upmix of the input signal is reproduced by all loudspeakers, whereas the level of the loudspeakers is adjusted according to the listener's position; or by the loudspeakers closest to the listener; or by some of the loudspeakers, which are selected by their position relative to the listener and/or relative to the other loudspeakers.

In a 9th further embodiment, based on a preceding embodiment, the sound or the sound image is rendered, such that it is moved translational with a listener. In other words the sound image is rendered, such that it follows the translational movement of the listener. For example, a perceived spatial image or sound image (as perceived by the listener) is moved. (for example, in dependence on a movement of the listener).

In a 10th further embodiment, based on a preceding embodiment, the sound or the sound image (for example, as generated using the loudspeaker signal and as perceived by the listener) is rendered, such that it is always moving according to a listener's orientation. In other words the sound image is rendered, such that it follows orientation of the listener.

In the following, it will be described how embodiments according to the invention help to improve conventional solutions.

A conventional simple solution for a multi-room playback system or an audio reproduction system is an amplifier or an audio/video receiver that offers multiple outlets for loudspeaker systems. This can be, for example, four outlets for two <NUM>-channels stereo pairs, or seven outlets for five channels surround plus one <NUM>-channel stereo pair. The selection which loudspeaker setups is/are playing can be done by switchover on the amplifier or audio/video receiver (AVR). In contrast to conventional solutions, according to an aspect, the current invention allows an automatic switching based on the listener's position, and the played back signal (e.g. automatically) is adapted to the listener's position or the actual setup of the loudspeaker system.

Today more advance multi-room systems are available which often consist of some main or control device, and additional devices, like wireless, active loudspeakers. Wireless means that they can receive signals wirelessly from either the control device, or from a mobile device as for example a smartphone. With some of those conventional systems, it is already possible to control the sound playback from the mobile smart device, so that the listener can play back music in the actual room he/she is in, even if the wireless loudspeaker is present there. Some conventional systems, even allow simultaneous playback of the same or different content in different rooms, and/or can be controlled via voice commands. In contrast to the conventional solutions, the present invention includes an automatic following of the listener into different rooms. In conventional solutions, the playback rather follows the playback device, and the pairing with a present loudspeaker has to be performed manually. Further, according to an aspect of the current invention, the playback signal is adapted to the listener's position or the actual setup of the loudspeaker system.

Some of such conventional systems using wireless loudspeakers offer the option to combine two of the wireless active mono loudspeakers to act as a stereo loudspeaker pair. Also, some conventional systems offer a stereo or multi-channel main device, like a sound bar, which can be extended by up to two wireless active loudspeakers that act as surround loudspeakers. Some advanced conventional systems, as part of home automation systems, with a large central control device are also offered and can be equipped with loudspeakers. These conventional solutions include already personalization options, based on, for example, time information, like a system can wake you up in the morning with your favorite song. Another form of personalization is that this conventional system can start playing music as soon as a person enters a room. This is achieved by coupling the playback to a motion sensor, or alternatively, a switch button, like next to the light switch can switch on and off the music in this room. While the conventional approach can already include some kind of an automatic following of the listener into different rooms, it only starts and stops playback using the loudspeakers in this room. In contrast, according to an aspect, the inventive solution continuously adapts the playback to the listener's position or to the actual setup of the loudspeaker system, for example loudspeakers in different rooms are seen as different zones, and such as individual separated playback systems.

Conventional methods for audio rendering that are aware of the listener's position have been proposed, e.g. as described in [<NUM>] by tracking a listener's position and adjusting gain and delay to compensate deviations from the optimal listening position. Listener tracking has also been used with crosstalk cancelation (XTC), for example in [<NUM>]. XTC requires extremely precise positioning of a listener, which makes listener tracking almost indispensable. In contrast to conventional methods of rendering with listener tracking, according to an aspect, the inventive solution allows to involve different loudspeaker setups or loudspeakers in different rooms as well.

In contrast to conventional solutions for audio following the listener as described, according to an aspect, the inventive method not only switches on and off the loudspeakers in different rooms or zones, but generates a seamless adaptation and transition. For example, while the listener is transitioning between two zones, or setups, both systems are not only switched on and off, but used to generate a pleasant sound image even in the transition zone. This is achieved by rendering specific loudspeaker feeds that take into account available information about the loudspeakers, like position relative to the listener and relative to the other loudspeakers, and frequency characteristics.

Embodiments of the invention relate to a system for reproducing audio signals in sound reproduction systems comprising a varying number of loudspeakers of potentially different kinds and at various positions. The loudspeakers can be located, for example, in different rooms and belong to, for example, individual separated loudspeaker setups, or loudspeaker zones. According to a main focus of the invention, the audio playback is adapted such that for a moving listener a desired playback is achieved throughout a large listening area instead of just a single point or a limited area, by tracking the user location and (optionally) orientation and adapting the orientation and adapting the rendering procedure accordingly. According to a second focus of the invention, such advanced user-adaptive rendering can even be carried out between several different rooms and loudspeaker zones or loudspeaker setups. Utilizing knowledge about the position of loudspeakers and the position and/or orientation of a listener, the audio reproduction is optimized and the audio signal is optimally rendered using the available loudspeakers, or reproduction systems. According to an aspect, the proposed invented method combines the benefits of a multi-room system and a playback system with listener tracking, in order to provide a system that automatically tracks a listener and allows, that the sound playback follows the listener through a space, like different rooms in a house, always making the best possible use of available loudspeakers in a room or a rear to produce a faithful and pleasing auditory impression.

The inventive method can follow different, user selectable, rendering schemes. The complete spatial image of the audio reproduction can follow the listener either by translational movement, that is with constant spatial orientation, and by rotational movement, where the spatial image is oriented relative to the listener's orientation. The spatial image can follow the listener smoothly, with defined follow times. This means that changes do not happen immediately, but the translational or rotational changes, or a combination of both, adapt within adjustable time constants to the new listener position.

The position of the loudspeakers can either be explicit, meaning the coordinates are in a fixed coordinate system, or implicit, where the loudspeakers are set up according to an ITU setup with a given radius.

The system can optionally have knowledge about the surroundings of the known loudspeakers, that means it knows for example that if we have two rooms with two loudspeaker setups that there are walls between those rooms, it may know the position of the walls, and the position of the doors and/or passages, that means it can know the partitioning of the acoustic space. Moreover, the system can possess information about the acoustical characteristic, such as absorption and/or reflection, etc., of the environment, walls, etc..

The spatial image can follow the listener within definable time constants. For some situations, it can be advantageous if the following of the sound image does not happen immediately, but with a time constant such that the spatial image slowly follows the listener.

The described inventive method and concepts can also similarly be applied if the input sound has been recorded or is delivered in ambisonics format or higher order ambisonics format. Also, binaural recordings, and similar other recording and production format can be processed by the inventive method.

A further rendering example is the best efforts rendering. While the listener is moving, situations may occur in which, for example, only a single loudspeaker is present in the area where one or more objects should be rendered, or the present loudspeakers in this area are spaced far from each other or cover a very large angle. In such cases, best efforts rendering is applied. As a parameter, for example the maximum allowed distance between two loudspeakers, or a maximum angle can be defined up to which, for example pair-wise panning will be used. If the available loudspeakers exceed the specified limit, like distance or angle, only the single closest loudspeaker will be selected for the reproduction of an audio object. If this results in cases where more than one object have to be reproduced from only a single loudspeaker, an (active) downmix is used to generate loudspeaker feed or a loudspeaker signal from the audio object signals.

A further example to loudspeaker selection is the snap-to-closest loudspeaker method. One specific example of the described approach is the snap-to-closest loudspeaker case. In this example, always only a single closest loudspeaker (or, alternatively, a plurality of the closest loudspeakers) is selected to reproduce an object, or a downmix of objects. Using a definable adjustment time or fading time or crossfade time, the objects are always reproduced using the loudspeaker closest to their position relative to the listener (or, alternatively, by the selected group of the closest loudspeakers). While the listener is moving, the selected group of (one or more) loudspeakers used for reproduction is constantly adapted to the listener's position. One parameter in the system defines a minimum respectively maximum distance that the loudspeakers have to have, respectively are allowed to have. Loudspeakers are only considered for inclusion if they are closer to the listener than the predefined minimum distance, or maximum distance. Similarly, if a listener moves away from a specific loudspeaker, exceeding the defined maximum distance, then the loudspeaker, respectively its contribution, is faded out and eventually switched off, respectively not considered for reproduction any longer.

The term 'loudspeaker layout' is used above in different meanings. For clarification, the following distinction is made.

The reference layout is an arrangement of loudspeakers as it has been used during the monitoring of the audio production during the mixing and mastering process.

It is defined by a number of loudspeakers at defined positions like azimuth and elevation, usually all loudspeakers are tilted such that they are directly facing the listener in the sweet spot, the place equidistant from all loudspeakers. Usually for channel based productions, a direct mapping between the content on the medium and the associated loudspeakers is made.

For example by a two channel stereo: two loudspeakers are positioned equidistantly in front of a listener, at ear height, with an azimuth of -<NUM>° for the left channel, and <NUM>° for the right channel. On two-channel media, the signal for the left channel, which is associated to the left loudspeaker, is conventionally the first channel, the signal for the right channel is conventionally the second channel.

We denote the actual loudspeaker setup that we find in the listening environment or in the reproduction environment as reproduction layout. Audio enthusiasts take care that their domestic reproduction layout is compliant with the reference layout for the inputs they use, for example a two channel stereo, or <NUM> surround, or <NUM>+<NUM> immersive sound. However, standard consumers often do not know how to set up loudspeakers correctly, and such the actual reproduction layout deviates from the intended reference layout. This has drawbacks, since:
Only if the reproduction layout matches the reference layout, a correct playback as intended by the producer is possible. Every deviation of the reproduction layout from the reference layout will lead to deviations in the perceived sound image from the intended sound image. The inventive method helps to remedy this problem.

The term "setup" or "loudspeaker setup" is also used above. By that, we mean a group of loudspeakers that is capable of generating a complete sound image in itself. The loudspeakers belonging to a setup are simultaneously addressed or fed with signals. Such, a setup can be a subset of all loudspeakers available in an environment.

The terms layout and setup are closely related. So, similar to the definition above, we can speak of a reference layout and a reproduction layout.

Claim 1:
An audio signal processor (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) for providing a plurality of loudspeaker signals (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) on the basis of a plurality of input signals (<NUM>, <NUM>,<NUM>, <NUM>, <NUM>),
wherein the audio signal processor is configured to obtain an information about a position of a listener (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>);
wherein the audio signal processor is configured to obtain an information about positions of a plurality of loudspeakers (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>);
wherein the audio signal signal processor is configured to dynamically allocate loudspeakers (<NUM>, <NUM>, <NUM>, LSS1_L, LSS1_C, LSS1_R, LSS1_SL, LSS1_SR, LSS2_L, LSS2_C, LSS2_R, LSS2_SL, LSS2_SR, LSS1_1, LSS1_2, LSS1_3, LSS1_4, LSS1_5, LSS2_1, LSS2_2, LSS3_1) for playing back objects and/or channel objects (<NUM>, <NUM>, <NUM>) and/or adapted signals (807a, 807b, 807c, <NUM>) derived from the input signals, in dependence on the information about the position of the listener and in dependence on the information about positions of the loudspeakers;
wherein the audio signal processor is configured to render (<NUM>, <NUM>, <NUM>, <NUM>) the objects and/or the channel objects and/or the adapted signals derived from the input signals, in dependence on the information about the position of the listener and in dependence on the information about positions of the loudspeakers, in order to obtain the loudspeaker signals such that a rendered sound follows the listener (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) when the listener moves or turns;
wherein the audio signal processor is configured
to identify loudspeakers dynamically in a predetermined environment of the listener, based on a distance between the listener and the loudspeaker, and
to adapt a configuration of the input signals to the number of identified loudspeakers, and
to dynamically allocate the identified loudspeakers for playing back the objects and/or channel objects and/or adapted signals, and
to render objects and/or channel objects and/or adapted signals to loudspeaker signals of associated loudspeakers in dependence on position information of objects and/or channel objects and/or adapted signals and in dependence on a default loudspeaker position.