(19)
(11)EP 2 975 864 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
13.05.2020 Bulletin 2020/20

(21)Application number: 14177369.7

(22)Date of filing:  17.07.2014
(51)Int. Cl.: 
H04S 5/00  (2006.01)

(54)

Signal processing apparatus for a vehicle sound system and signal processing method for a vehicle sound system

Signalverarbeitungsvorrichtung für ein Fahrzeug und Signalverarbeitungsverfahren für ein Kraftfahrzeug-Soundsystem

Appareil de traitement de signal pour système audio pour automobile et procédé de traitement de signaux pour un système acoustique de véhicule


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(43)Date of publication of application:
20.01.2016 Bulletin 2016/03

(73)Proprietor: Alpine Electronics, Inc.
Tokyo (JP)

(72)Inventor:
  • Esser, Timo
    70567 Stuttgart (DE)

(74)Representative: Schmitt-Nilson Schraud Waibel Wohlfrom Patentanwälte Partnerschaft mbB 
Pelkovenstraße 143
80992 München
80992 München (DE)


(56)References cited: : 
EP-A1- 2 190 221
WO-A1-2008/108968
WO-A1-2014/088328
US-A1- 2012 008 789
EP-A1- 2 629 552
WO-A1-2010/027882
US-A1- 2006 222 187
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description


    [0001] The present invention is in the field of sound systems for passenger transport vehicles, such as cars, buses and trucks. In particular, the present invention is in the field of a signal processing apparatus for a vehicle sound system and a signal processing method for a vehicle sound system.

    [0002] It has long been known in the art to equip passenger transport vehicles with sound systems. Such sound systems are in use for listening to music, news, audio books, audio documentaries and other audio content. As compared to home sound systems, the room acoustics inside a vehicle provide a perceived sound quality that is significantly more inferior to a perfect listening room. Accordingly, it would be beneficial to provide means for a vehicle sound system that increase the perceived sound quality / sound experience for the user and that, in particular, provides an improved sound quality for various different types of audio content.

    [0003] EP 2 629 552 A1 discloses an audio surround processing system that receives an audio source signal having at least two audio channels and generates a number of additional surround sound signals in which an amount of artificially generated ambient energy is controlled in real-time at least in part by an estimate of ambient energy that is contained in the audio source signal. WO 2014/088328 discloses an appratus for upmixing signals to generate height signals using all available channels as input, without defining a specific equation for the upmix. WO 2010/027882 discloses the use of rear channels for generating height signals. US 2006/222187 discloses the use of front and rear channels to generate height signals, but in an application related to microphones and without separating left and right signals. US 2012/008789 discloses the use of front signals to generate height signals.

    [0004] The present invention is related to a signal processing apparatus, as claimed in claim 1, and a signal processing method, as claimed in claim 10. Further exemplary embodiments of the invention are disclosed in the dependent claims.

    [0005] The signal processing apparatus performs an up-conversion of the multi-channel audio signal. It generates at least two 3D audio signals, namely at least the left 3D signal and the right 3D signal, in addition to the multi-channel audio signal. As the left 3D signal and the right 3D signal are provided in addition to the left front signal, the left surround signal, the right front signal and the right surround signal, and as these signals are output via speakers in an upper portion of the vehicle, the passenger's audio experience is more voluminous. The passenger has the impression that he/she is listening to the audio content in a larger space. The left 3D signal and the right 3D signal are referred to as a left 3D height signal and a right 3D height signal, because these signals create the perceived height of the listening room, when output via the speakers in the upper portion of the vehicle.

    [0006] The left front signal and the left surround signal are separate inputs to the left room simulation function. Analogously, the right front signal and the right surround signal are separate inputs to the right room simulation function. With these signals being separate inputs, the room simulation functions are able to provide 3D sound that is adapted to the kind of audio content present. For example, with orchestra music having a large diffuse surround component, also referred to as uncorrelated sound component or reverb, the room simulation functions may provide strong 3D signals. In contrast thereto, in the example of the audio content being a news reader, which audio content typically has low or no reverb, the room simulation functions may provide weaker 3D signals. In this way, the signal processing apparatus allows for adding a high degree of 3D sound when appropriate in light of the type of audio content, while preventing an artificially sounding, excessive expansion of audio content when a large 3D sound component is not appropriate. At the same time, the signal processing apparatus allows for adding some 3D sound for all types of audio content, leading to an improved listening experience for all types of audio content. In other words, the signal processing apparatus comprises a room simulation module which always some 3D sound component, but only adds a large amount of 3D sound component when appropriate in light of the type of audio content. This can all be done in a fairly simple way through a single set of room simulation functions. No explicit distinction between different kinds of audio content and no application of different room simulation functions for different kinds of audio content is necessary.

    [0007] The room simulation functions simulate an auditory space. In other words, they add a simulated room effect to the multi-channel audio signal. They provide a simulated room transfer function to the multi-channel audio signal. While the room simulation functions rely on multiple inputs for adding the appropriate amount of room simulation, the overall perceived room is more than an extraction of particular signal components, such as reverb, from the source signal. The room simulation functions add a synthetic room which may depend in size and character on the room signal extracted from the original signal by the surround upmix at the input.

    [0008] The left 3D speaker and the right 3D speaker are positioned in an upper portion of an interior space of a vehicle. They may be positioned towards the front of the interior space or towards the rear of the interior space. It is also possible that there are more than two 3D speakers, such as four 3D speakers. In that case, the signal processing apparatus may provide the same 3D signal to two 3D speakers, respectively, or may provide distinct signals to all four 3D speakers. The term 3D speaker refers to a speaker that emits sounds in an upper portion of a vehicle, such as above a passenger's ear level and/or above the other main loudspeakers.

    [0009] The signal input section is coupled to the room simulation module. Further, the room simulation module is coupled to the signal output section. In addition, the signal output section may be coupled to the signal input section. In particular, the multi-channel audio signal may be provided directly from the signal input section to the signal output section. The signal input section may comprise a first stage of signal processing. However, it is also possible that the signal input section is only provided for passing an audio signal on from an audio source.

    [0010] The term speaker, as used throughout this disclosure, may refer to a single speaker, also referred to as loudspeaker. However, the term speaker may also refer to a set of speakers, covering different frequency ranges. For example, the term speaker may refer to a set of two speaker of selected frequencies. In particular, the term speaker may refer to the combination of a low frequency speaker and a high frequency speaker. It is equally possible that the term speaker refers to a set of three speakers, outputting low, medium and high frequencies, respectively. In the example of a right 3D speaker, it is possible that two or three speakers of different frequencies are provided in the right upper portion of the vehicle. These limited frequency speakers may be arranged in one housing or in separate housings in proximity of each other.

    [0011] According to the present invention, the left room simulation function weighs the left front signal and the left surround signal differently and the right room simulation function weighs the right front signal and the right surround signal differently. In other words, the left room simulation function has different weighing coefficients for the inputs of the left front signal and the left surround signal. Analogously, the right room simulation function has different weighing coefficients for the right front signal and the right surround signal. The room simulation functions then performs the room simulation on this weighed combination of the respective front and surround signals. This weighing of the front and surround signals provides for a fairly simple, closed implementation of the room simulation functions, applicable to all kinds of audio content.

    [0012] According to the present invention, the left room simulation function comprises a left room simulation component calculated as f11 LS + β1 LF), with LS denoting the left surround signal and LF denoting the left front signal and with a, being greater than β1, and wherein the right room simulation function comprises a right room simulation component calculated as f22 Rs + β2 RF), with Rs denoting the right surround signal and RF denoting the right front signal and with α2 being greater than β2. The given formulas with the given relationship between the weighing coefficients α and β allow for an optimized addition of room simulation, depending on the type of audio content, implemented as a single set of room simulation functions. The diffuse surround component is weighed stronger than the uncorrelated front signal. This leads to a very natural sound experience to the passenger, with the reverb portion of the multi-channel audio signal being the dominant portion in the processing and in the 3D speaker outputs. At the same time, a comparatively smaller 3D component is provided on the basis of the correlated front signal, leading to a voluminous sound experience also for highly correlated audio sources.

    [0013] The expressions "f1" and "f2" refer to functions that simulate an auditory space, thus contributing a room simulation that is an addition as compared to the multi-channel audio signal and that cannot be merely extracted from the multi-channel audio signal. In a particular embodiment, f1 and f2 can be the same. In other words the left room simulation component may be calculated in accordance with the same function as the right room simulation component. However, it is also possible that f1 and f2 are different functions. Also, while it is possible that α1 equals α2 and/or that β1 equals β2, it is also possible that α1 is different from α2 and/or that β1 is different from β2. In a particular embodiment, α1, is much greater than β1, i.e. more than 10 times greater. It is also possible that α2 is much greater than β2, i.e. at least 10 times greater. Such a relationship between the weighing coefficients allows for a particularly good compromise between some added room simulation for all types of audio content and a strong addition of room simulation when appropriate in light of the type of audio content in question.

    [0014] The left room simulation function may have the left room simulation component as the only signal component or may have other signal components, as discussed below. Analogously, the right room simulation function may have the right room simulation component as the only signal component or may have other signal components.

    [0015] According to a further embodiment, the left room simulation function comprises the left front signal and/or the left surround signal as an additive term, weighed by a respective coefficient, and the right room simulation function comprises the right front signal and/or the right surround signal as an additive term, weighed by a respective coefficient. The expression "additive term" refers to a component that contributes to the room simulation functions purely by addition. In other words, it refers to a linear term. For this additive term, no function adding room simulation or any other simulation is applied to the front signal and/or surround signal. The inclusion of such an additive term results in a greater sound stability, increasing the ease of listening as compared to a pure room simulation component being output via the 3D speakers.

    [0016] According to a further embodiment, the left room simulation function comprises a left sound stability component calculated as (γ1 LS + δ1 LF), with LS denoting the left surround signal and LF denoting the left front signal and with γ1 being greater than δ1, and the right room simulation function comprises a right sound stability component calculated as (γ2 RS + δ2 RF), with RS denoting the right surround signal and RF denoting the right being greater than δ2. In this way, both the respective front signal as well as the respective surround signal are included into the room simulation functions in a linear manner. Accordingly, above described addition of stability may be implemented in a straightforward manner on the basis of the same front signal and surround signal inputs, without a distinction with respect to the type of audio content being necessary. With the surround signal being weighed stronger than the front signal, a hollow overall sound due to the front signal being output from the upper portion of the vehicle in a dominant manner is prevented. In a particular embodiment γ1 is much greater than δ1, i.e. at least 10 times greater. It is also possible that γ2 is much greater than δ2, i.e. at least 10 times greater. Again, it is possible that γ1, and γ2 are the same or different and that δ1 and δ2 are the same or different.

    [0017] According to a further embodiment, α1, α2, β1 and β2 are greater than γ1, γ2, δ1 and δ2. In this way, it may be ensured that the respective room simulation components are greater than the respective sound stability components. In particular, α1, α2, β1 and β2 may be much greater than γ1 γ2, δ1, and δ2, i.e. at least 10 times greater. However, it is also possible that the particular implementations of f1 and f2 ensure that the room simulation components are greater than the sound stability components.

    [0018] According to a further embodiment, the left room simulation function comprises a left room simulation component and a left sound stability component, with the left room simulation component being greater than the left sound stability component, and wherein the right room simulation function comprises a right room simulation component and a right sound stability component, with the right room simulation component being greater than the right sound stability component. In this way, a comparatively larger room simulation component is combined with a comparatively smaller sound stability component, thus allowing for a dominant 3D room simulation, while at the same time ensuring a relaxing listening experience to the passenger. In a particular embodiment, the respective room simulation components may be much greater than the respective sound stability components, i.e. at least 10 times greater. The comparison between the components may be carried out on the basis of the component amplitudes or component powers or any other suitable metric. In a particular embodiment, the respective room simulation functions may consist of the respective room simulation component and the respective sound stability component. In other words, the respective room simulation and sound stability components may be the only components of the room simulation function in question.

    [0019] According to a further embodiment, the left and right room simulation functions are configured to simulate an auditory space that is larger than an interior space of a vehicle. In this way, the vehicle sound system makes the passenger feel like he is listening to the audio content in a room that is larger than the actual interior of the vehicle. In this way, superior acoustics can be simulated than can be achieved within the interior of the vehicle with prior art sound systems. In particular, the left and right room simulation functions may be adapted to simulate the reverb generated in an enclosed space when an audio source is played. In a particular embodiment, the left and right room simulation functions are configured to simulate an ideal auditory space. In a further particular embodiment, the left and right room simulation functions are configured to simulate an ideal auditory space of 4m x 6m x 2.5m.

    [0020] According to a further embodiment, the left 3D signal is a left front 3D signal and the right 3D signal is a right front 3D signal. Accordingly, the left 3D signal and the right 3D signal may be provided to the signal output section for being output to a left front 3D speaker and to a right front 3D speaker. Accordingly, the left 3D speaker may be a left front 3D speaker and the right 3D speaker may be a right front 3D speaker.

    [0021] According to a further embodiment, the room simulation module further comprises a left rear room simulation function generating a left rear 3D signal, with the left front signal and the left surround signal being inputs thereto, and a right rear room simulation function generating a right rear 3D signal, with the right front signal and the right surround signal being inputs thereto. In this way, front and rear signals are generated in the third dimension, leading to a surrounding of the passenger with speakers from all sides. In other words, an additional stereo surround sound is created in the upper portion of the vehicle, leading to an even more voluminous listening experience. The left rear 3D signal and the right rear 3D signal may be output to a left rear 3D speaker and a right rear 3D speaker. Accordingly, the output signal section may be configured for outputting the left rear 3D signal and the right read 3D signal to a left rear 3D speaker and a right rear 3D speaker.

    [0022] Above discussed features and modifications of the left room simulation function and the right room simulation function can be implemented with respect to the the left rear room simulation function and the right rear room simulation function in an analogous manner. According to a further embodiment, the multi-channel audio signal is an input signal stemming from an audio source. For example, the vehicle sound system may comprise a DVD drive or CD drive or a hard disk drive or any other suitable means for reading out a memory containing the audio source signal. It is also possible that the audio source signal is transferred to the vehicle in a wireless manner. Notwithstanding which source the audio input signal is coming from, the input signal may be a multi-channel signal that already contains the left front signal, the left surround signal, the right front signal, and the right surround signal. An example for such an input signal is a 5.1 surround sound signal. It is also possible that the input signal is a different kind of multi-channel audio signal having above discussed four signals.

    [0023] According to an alternative embodiment, the input signal section comprises an audio signal conversion module, with the audio signal conversion module being adapted to generate the multi-channel audio signal from an input signal missing at least one of the left front signal, the left surround signal, the right front signal and the right surround signal, such as from a two-channel stereo input signal. In this way, the room simulation module can also be put to use for audio source signals that lack one of above discussed four signals. In particular, the audio signal conversion module may be adapted to extract a left surround signal and a right surround signal from a two-channel stereo input signal. Accordingly, above-discussed features of room simulation simulation can be achieved via subsequent operations of audio signal conversion and room simulation generation. For this purpose, the audio signal conversion module may be coupled to the room simulation module, either directly or via other signal processing modules, such as via a volume and/or fading and/or balance adaptation module. With an appropriate audio signal conversion module, any kind of audio source can be pre-processed for the ensuing room simulation simulation by the room simulation module. For example, the audio source may be any of a 1.0 mono source, a 2.0 stereo source, a 5.1 surround source, a 5.2 surround source, a 7.1 surround source or any other audio source. In an exemplary embodiment, the audio signal conversion module may be implemented in any of the manners described in EP 1 722 598 A2 with respect to the audio device of said document. The contents of said document is incorporated herein in its entirety.

    [0024] Exemplary embodiments of the invention further include a vehicle sound system comprising a plurality of speakers, the plurality of speakers comprising a left 3D speaker and a right 3D speaker, the left 3D speaker and the right 3D speaker being configured to be disposed in an upper portion of a vehicle, the vehicle sound system further comprising a signal processing apparatus in accordance with any of the embodiments described above, with the signal processing apparatus being coupled to the left 3D speaker and the right 3D speaker for outputting the left 3D signal and the right 3D signal thereto. The additional features and modifications described above with respect to the signal processing apparatus may equally be applied to the vehicle sound system. Above discussed advantages are also attainable with the vehicle sound system.

    [0025] The plurality of speakers of the vehicle sound system may comprise a left front speaker, a left surround speaker, a right front speaker, a right surround speaker. It may also include additional speaker, such as a center front speaker, a subwoofer, left and right rear speakers. The left and right 3D speakers may be left and right front 3D speakers or left and right rear 3D speakers. It is also possible that the vehicle sound system has left and right front 3D speakers as well as left and right rear 3D speakers. The signal processing apparatus may be coupled to all speakers present in the vehicle sound system. The vehicle sound system may also comprise an audio source reading apparatus, such as a CD player or DVD player or hard disk drive, and/or an audio signal reception apparatus, such as a radio receiver.

    [0026] Exemplary embodiments of the invention further include a passenger transport vehicle, such as a car, bus or truck, comprising a vehicle sound system, as described above, which includes a signal processing apparatus, as described in any of the embodiments above, with the vehicle sound system being installed in the passenger transport vehicle with the left 3D speaker and the right 3D speaker being disposed in an upper portion of the passenger transport vehicle. The additional features and modifications described above with respect to the signal processing apparatus and with respect to the vehicle sound system may equally be applied to the passenger transport vehicle. Above discussed advantages are also attainable with the passenger transport vehicle.

    [0027] Exemplary embodiments of the invention further include a signal processing method for a vehicle sound system, the method comprising the steps of receiving a multi-channel audio signal comprising at least a left front signal, a left surround signal, a right front signal and a right surround signal, generating at least a left 3D signal and a right 3D signal for providing a room simulation by the vehicle sound system, with the left front signal and the left surround signal being inputs to a left room simulation function that generates the left 3D signal and with the right front signal and the right surround signal being inputs to a right room simulation function that generates the right 3D signal, and outputting the left 3D signal and the right 3D signal to a left 3D speaker and a right 3D speaker disposed in an upper portion of a vehicle. The additional features and modifications described above with respect to the signal processing apparatus may equally be applied to the signal processing methods. According modifications of the signal processing methods are herewith disclosed. Above discussed advantages are also attainable with the signal processing method.

    [0028] Embodiments of the invention are described in greater detail below with reference to the figures, wherein:

    Fig. 1 shows a perspective schematic view of an exemplary vehicle having an exemplary vehicle sound system in accordance with the invention installed therein.

    Fig. 2 shows a block diagram of an exemplary signal processing apparatus in accordance with the invention.



    [0029] Fig. 1 shows a perspective schematic diagram of a passenger transport vehicle 4, having a vehicle sound system 2 in accordance with an exemplary embodiment of the invention. The vehicle sound system 2 comprises twelve speakers. In particular, the vehicle sound system comprises a left front speaker 21, a left rear speaker 31, a left surround speaker 23, a right front speaker 22, a right rear speaker 32, a right surround speaker 24, a left front 3D speaker 25, a right front 3D speaker 26, a left rear 3D speaker 27, a right rear 3D speaker 28, a center front speaker 29, and a subwoofer 30. All of these speakers are coupled to a signal processing apparatus 6 by individual signal lines (shown in dashed lines in Fig. 1). It is also possible that all of the speakers 21-32 and the signal processing apparatus 6 are coupled via a bus architecture or any other means of signal communication.

    [0030] The vehicle sound system 2 may comprise an audio signal receiving apparatus, such as a tuner, for receiving wireless audio source signals, such as radio broadcast waves or any other kind of signal / data transmission. Additionally/alternatively, it is possible that the vehicle sound system 2 is coupled to an audio source reading apparatus, such as a CD player or a DVD player or a hard disk drive or any other kind of signal / data storage device. The audio signal receiving apparatus and/or the audio source reading apparatus may be coupled to the signal processing apparatus 6 for providing the audio source signal to the signal processing apparatus 6. No matter what the audio source is, the signal processing apparatus is adapted to receive the audio source signal and to generate respective output signals for the plurality of speakers.

    [0031] Fig. 2 shows a signal processing apparatus 6 in accordance with an exemplary embodiment of the invention. The signal processing apparatus 6 comprises a signal input section 62, a room simulation module 64, and a signal output section 66. The exemplary signal processing apparatus 6 is described with a stereo signal being the audio source, which consists of the left source signal LSource and the right source signal RSource, and with the output signal consisting of twelve signals for being output to the twelve speakers of the vehicle 4 described above.

    [0032] The signal input section 62 comprises an audio signal conversion module 70 and a audio signal conditioning module 72. The audio signal conversion module 70 performs an up-conversion of the two-channel stereo input signal. In particular, the audio signal conversion module 70 generates a left front signal LF, a right front signal RF, a left surround signal Ls, a right surround signal RS, a center front signal C and a subwoofer signal LFE (with LFE denoting "low frequency effects"). Such up-conversion of a two-channel stereo signal into a 5.1 surround signal via the audio signal conversion module 70 is per se known in the art.

    [0033] The up-converted audio signal is then input into the audio signal conditioning module 72. The audio signal conditioning module 72 is configured to adapt the volume, fading, balance and subwoofer levels of the audio signals. Such signal conditioning is also per se known in the art. Depending on the complexity of the vehicle sound system, the audio signal conditioning module 72 may have different functionality and different degrees of signal conditioning. It is also possible that the audio signal conditioning module 72 is dispensed with and that only a simple volume scaling takes place. The only essential aspect with respect to the signal input section 62 is that a multi-channel signal is provided via the signal input section, which multi-channel audio signal contains a left front signal, a left surround signal, a right front signal and a right surround signal. If the audio source already provides such multi-channel audio signal, such as a 5.1 surround signal, the signal input section may consist of a mere passing on of the source signal.

    [0034] The room simulation module 64 is coupled to the signal input section 62 in such a way that the left front signal LF, the left surround signal LS, the right front signal RF and the right surround signal RL are provided by the signal input section 62 to the room simulation module 64. Based on these four signals, the room simulation module 64 generates four 3D signals, which are configured to be output to four speakers disposed in the upper portion of the vehicle. In particular, the room simulation module 64 generates a left front 3D signal, a right front 3D signal, a left rear 3D signal and a right rear 3D signal. These four 3D signals are generated by the room simulation module 64 in the manner described below.

    [0035] The left front 3D signal LF3D is generated by a left front room simulation function in accordance with the following formula:



    [0036] The right front 3D signal RF3D is generated by a right front room simulation function in accordance with the following formula:



    [0037] The left rear 3D signal LR3D is generated by a left rear room simulation function in accordance with the following formula:



    [0038] The right rear 3D signal RR3D is generated by a right rear room simulation function in accordance with the following formula:



    [0039] The parameters αx, βx, γx and δx are weighing coefficients that allow for a relative scaling of the impact of the left front signal LF, the left surround signal LS, the right front signal RF and the right surround signal RS on the respective 3D signal. In the exemplary embodiment described, αx is much greater than βx, in particular at least 10 times greater, for x being 1, 2, 3 and 4. Also, in the exemplary embodiment described, γx is much greater than δx, in particular at least 10 times greater, for x being 1, 2, 3 and 4. In the exemplary embodiment of Fig. 2, αx and βx are greater than yx and δx, in particular much greater, i.e. at least 10 times greater, for x being 1, 2, 3 and 4.

    [0040] The four room simulation functions given above each comprise a room simulation component and a sound stability component. The room simulation components are calculated via the functions f1, f2, f3 and f4. These functions simulate an auditory space. In particular, the functions f1, f2, f3 and f4 are adapted - on the basis of the weighed inputs - to mimic the audio experience a listener would have in a space that is larger than the interior of the passenger transport vehicle. In particular, the functions f1, f2, f3 and f4 may be configured to generate the reverb that would be generated by the structure of an enclosed room. In particular, the functions f1, f2, f3 and f4 may simulate an ideal auditory space, such as an auditory space of 4m x 6m x 2.5m.

    [0041] The respective sound stability components consist of an addition of the respective left or right surround signal and of the respective left or right front signal, weighed by a respective weighing coefficient γx or δx. No further function apart from the weighing coefficients is applied to the inputs for the sound stability components.

    [0042] In this way, multiple effects are achieved, as already discussed in detail above. As the room simulation is dependent on both the respective surround signal and the respective front signal and as these two inputs are weighed differently, an appropriate room simulation is generated for all types of audio content. Audio content with a large surround sound component, such as orchestra music, leads to strong 3D signals, i.e. to a strong room simulation. In this way, an appropriate amount of 3D simulation is presented to the listener. In contrast thereto, for audio content not having a large surround component, such as news speakers or similar content, the room simulation functions generate a lower amount of room simulation. This lower amount of room simulation ensures that the news speaker is not perceived as talking in a large hall with a lot of echo effect on the one hand. On the other hand, the generation of a comparatively low level of room simulation still provides for a voluminous sound experience in the vehicle environment.

    [0043] The signal output section 66 is coupled to both the signal input section 62 and the room simulation module 64. It is configured to receive the left front signal, the left surround signal, the right front signal, the right surround signal, the center front signal and the subwoofer signal from the input section 62. Further, it is configured to receive above discussed four 3D signals, namely the left front 3D signal LF3D, the right front 3D signal RF3D, the left rear 3D signal LR3D, and right rear 3D signal RR3D from the room simulation module 64. The signal output section 66 is provided for outputting twelve signals to the respective speakers in the passenger transport vehicle.

    [0044] In the exemplary embodiment of Fig. 2, the signal output section 66 comprises a mixer module 74. This mixer module 74 allows for a combining or shuffling of the signals before being output to the speakers. In the exemplary embodiment of Fig. 2, the mixer module 74 passes some of the signals on and generates some signals by combination. In particular, the mixer module 74 passes on the left front signal LF, the right front signal RF, the center front signal C, the subwoofer signal LFE, the left front 3D signal LF3D, the right front 3D signal RF3D, the left rear 3D signal LR3D, and right rear 3D signal RR3D to the left front speaker 21, the right front speaker 22, the center front speaker 29, the subwoofer 30, the left front 3D speaker 25, the right front 3D speaker 26, the left rear 3D speaker 27, and the right rear 3D speaker 28, respectively. The mixer module 74 further generates an updated left surround signal LS', an updated right surround signal RS', a left rear signal LR, and a right rear signal RR. The updated left surround signal LS', the updated right surround signal RS', the left rear signal LR, and the right rear signal RR. are output to the left surround speaker 23, the right surround speaker 24, the left rear speaker 31, and the right rear speaker 31. These signals are generated in accordance with the following formulas:









    [0045] In the exemplary embodiment of Fig. 2, αx is much greater than βx, in particular at least 10 times greater, for x being 5 and 6. In this way, the updated surround signals LS' and RS' are dominated by the surround signals LS and RS, but have a slight component of the respective front signal LF and RF for a more voluminous sound experience. In the exemplary embodiment of Fig. 2, αx and βx are comparable in magnitude, i.e. they are less than a factor 10 different, in particular less than a factor 5 different, even more in particular less than a factor 2 different, for x being 7 and 8. In this way, the sound from the left and right rear speakers 31 and 32 provides for a natural sound experience between the left and right front speakers 21 and 22 on the one side and the left and right surround speaker 23 and 24 on the other side.

    [0046] It is pointed out that the combining or shuffling provided by the mixer module 74 may be desirable in some application scenarios. However, it is also possible that the mixer module 74 be dispensed with, and that the audio signals may be passed on to the speakers as they are. In this case, it is for example possible to pass on the left surround signal Ls and the right surround signal Rs to the left and right surround speakers 23 and 24, as they are. It is further for example possible to provide the rear speakers 31 and 32 with the respective surround signals LS and RS or with the respective front signals LF and RF. In general, it is possible that the signal output section 66 is provided for passing on the audio signals to the speakers only.

    [0047] The signal input section, the room simulation module, and the signal output section may be implemented in any appropriate manner. They may be implemented in hardware, such as in digital signal processing components. They may also be implemented in software or in any appropriate combination of hardware and software.


    Claims

    1. Signal processing apparatus (6) for a vehicle sound system (2), comprising:

    a signal input section (62), through which in operation a multi-channel audio signal is provided, the multi-channel audio signal comprising at least a left front signal (LF), a left surround signal (LS), a right front signal (RF) and a right surround signal (RS),

    wherein the signal processing apparatus (6) further comprises:

    a room simulation module (64) adapted to receive the multi-channel audio signal and to generate at least a left 3D height signal (LF3D) and a right 3D height signal (RF3D), with the room simulation module (64) comprising a left room simulation function generating the left 3D height signal (LF3D), with the left front signal (LF) and the left surround signal (Ls) being inputs thereto, and a right room simulation function generating the right 3D height signal (RF3D), with the right front signal (RF) and the right surround signal (Rs) being inputs thereto,

    wherein the left room simulation function is a left front room simulation function, wherein the right room simulation function is a right front room simulation function, wherein the left 3D height signal (LF3D) is a left front 3D height signal and wherein the right 3D height signal (RF3D) is a right front 3D height signal, and

    wherein the left room simulation function comprises a left room simulation component calculated as f1,(α1 Ls + β1 LF), with LS denoting the left surround signal and LF denoting the left front signal and with α1 being greater than β1, and wherein the right room simulation function comprises a right room simulation component calculated as F22 RS + β2 RF), with RS denoting the right surround signal and RF denoting the right front signal and with α2 being greater than β2, and

    a signal output section (66) for outputting the left 3D height signal (LF3D) and the right 3D height signal (RF3D) to a left 3D speaker (25) and a right 3D speaker (26) disposed in an upper front portion of a vehicle.


     
    2. Signal processing apparatus (6) according to claim 1, wherein the left room simulation function comprises a left sound stability component calculated as (γ1 LS + δ1 LF), with LS denoting the left surround signal and LF denoting the left front signal and with y, being greater than δ1 and wherein the right room simulation function comprises a right sound stability component calculated as (γ2 RS + δ2 RF), with RS denoting the right surround signal and RF denoting the right front signal and with γ2 being greater than δ2.
     
    3. Signal processing apparatus (6) according to claim 1 or 2, wherein the left room simulation function comprises a left room simulation component and a left sound stability component, with the left sound stability component comprising the left front signal (LF) and the left surround signal (LS) as an additive term, weighed by a respective coefficient, and with the left room simulation component being greater than the left sound stability component, and wherein the right room simulation function comprises a right room simulation component and a right sound stability component, with the right sound stability component comprising the right front signal (RF) and the right surround signal (Rs) as an additive term, weighed by a respective coefficient, and with the right room simulation component being greater than the right sound stability component.
     
    4. Signal processing apparatus (6) according to any of the preceding claims, wherein the left and right room simulation functions are configured to simulate an auditory space that is larger than an interior space of a vehicle.
     
    5. Signal processing apparatus (6) according to any of the preceding claims, wherein the room simulation module (64) further comprises a left rear room simulation function generating a left rear 3D height signal (LR3D), with the left front signal (LF) and the left surround signal (LS) being inputs thereto, and a right rear room simulation function generating a right rear 3D height signal (RR3D), with the right front signal (RF) and the right surround signal (RS) being inputs thereto.
     
    6. Signal processing apparatus (6) according to any of the preceding claims, wherein the multi-channel audio signal is an input signal stemming from an audio source.
     
    7. Signal processing apparatus (6) according to any of claims 1 to 5, wherein the input signal section (62) comprises an audio signal conversion module (70), with the audio signal conversion module (70) being adapted to generate the multi-channel audio signal from an input signal missing at least one of the left front signal, the left surround signal, the right front signal and the right surround signal, such as from a two-channel stereo input signal.
     
    8. Vehicle sound system (2) comprising a plurality of speakers, the plurality of speakers comprising a left front 3D speaker (25) and a right front 3D speaker (26), the left front 3D speaker (25) and the right front 3D speaker (26) being configured to be disposed in an upper front portion of a vehicle (4),
    the vehicle sound system (2) further comprising a signal processing apparatus (6) according to any of the preceding claims, with the signal processing apparatus (6) being coupled to the left front 3D speaker (25) and the right front 3D speaker (26) for outputting the left 3D height signal (LF3D) and the right 3D height signal thereto (RF3D).
     
    9. Passenger transport vehicle (4), such as a car, bus or truck, comprising a vehicle sound system (2) according to claim 8, the vehicle sound system (2) being installed in the passenger transport vehicle with the left front 3D speaker (25) and the right front 3D speaker (26) being disposed in an upper front portion of the passenger transport vehicle (4).
     
    10. Signal processing method for a vehicle sound system, the method comprising the step of:
    receiving a multi-channel audio signal comprising at least a left front signal (LF), a left surround signal (LS), a right front signal (RF) and a right surround signal (RS),
    wherein the signal processing method further comprises the steps of:

    generating at least a left 3D height signal (LF3D) and a right 3D height signal (RF3D) for providing a room simulation by the vehicle sound system, with the left front signal (LF) and the left surround signal (LS) being inputs to a left room simulation function that generates the left 3D height signal (LF3D) and with the right front signal (RF) and the right surround signal (RS) being inputs to a right room simulation function that generates the right 3D height signal (RF3D),

    wherein the left room simulation function is a left front room simulation function, wherein the right room simulation function is a right front room simulation function, wherein the left 3D height signal is a left front 3D height signal and wherein the right 3D height signal is a right front 3D height signal, and

    wherein the left room simulation function comprises a left room simulation component calculated as f1,(α1 LS + β1 LF), with LS denoting the left surround signal and LF denoting the left front signal and with α1, being greater than β1, and wherein the right room simulation function comprises a right room simulation component calculated as f22 RS + β2 RF), with RS denoting the right surround signal and RF denoting the right front signal and with α2 being greater than β2, and

    outputting the left 3D height signal (LF3D) and the right 3D height signal (RF3D) to a left 3D speaker (25) and a right 3D speaker (26) disposed in an upper front portion of a vehicle.


     


    Ansprüche

    1. Signalverarbeitungsvorrichtung (6) für ein Fahrzeug-Soundsystem (2), die umfasst:

    einen Signaleingabeabschnitt (62), durch den im Betrieb ein Mehrkanalaudiosignal bereitgestellt wird, wobei das Mehrkanalaudiosignal mindestens ein Signal (LF) für links vorne, ein Surround-Signal (LS) für links, ein Signal (RF) für rechts vorne und ein Surround-Signal (RS) für rechts umfasst, wobei

    die Signalverarbeitungsvorrichtung (6) ferner umfasst:

    ein Raumsimulationsmodul (64), das dafür ausgebildet ist, das Mehrkanalaudiosignal zu empfangen und mindestens ein 3D-Höhe-Signal (LF3D) für links und ein 3D-Höhe-Signal (RF3D) für rechts zu erzeugen, wobei das Raumsimulationsmodul (64) eine Simulationsfunktion für den linken Raum, die das 3D-Höhe-Signal (LF3D) für links erzeugt, wobei das Signal (LF) für links vorne und das Surround-Signal (LS) für links Eingaben darin sind, und eine Simulationsfunktion für den rechten Raum, die das 3D-Höhe-Signal (RF3D) für rechts erzeugt, wobei das Signal (RF) für rechts vorne und das Surround-Signal (RS) für rechts Eingaben darin sind, umfasst,

    wobei die Simulationsfunktion für den linken Raum eine Simulationsfunktion für den linken vorderen Raum ist, wobei die Simulationsfunktion für den rechten Raum eine Simulationsfunktion für den rechten vorderen Raum ist, wobei das 3D-Höhe-Signal (LF3D) für links ein 3D-Höhe-Signal für links vorne ist und wobei das 3D-Höhe-Signal (RF3D) für rechts ein 3D-Höhe-Signal für rechts vorne ist, und

    wobei die Simulationsfunktion für den linken Raum eine Simulationskomponente für den linken Ram umfasst, die als f11 LS + β1 LF) berechnet wird, wobei LS das Surround-Signal für links kennzeichnet und LF das Signal für links vorne kennzeichnet und wobei α1 größer ist als β1 und wobei die Simulationsfunktion für den rechten Raum eine Simulationskomponente für den rechten Raum umfasst, die als f22 RS + β2 RF) berechnet wird, wobei RS das Surround-Signal für rechts kennzeichnet und RF das Signal für rechts vorne kennzeichnet und wobei α2 größer ist als β2,

    und

    einen Signalausgabeabschnitt (66) für die Ausgabe des 3D-Höhe-Signals (LF3D) für links und des 3D-Höhe-Signals (RF3D) für rechts an einen linken 3D-Lautsprecher (25) und einen rechten 3D-Lautsprecher (26), die in einem oberen vorderen Teils eines Fahrzeugs angeordnet sind.


     
    2. Signalverarbeitungsvorrichtung (6) nach Anspruch 1, wobei die Simulationsfunktion für den linken Raum eine Soundstabilitätskomponente für links umfasst, die als (γ1 LS + δ1 LF) berechnet wird, wobei LS das Surround-Signal für links kennzeichnet und LF das Signal für links vorne kennzeichnet und wobei γ1 größer ist als δ1 und wobei die Simulationsfunktion für den rechten Raum eine Soundstabilitätskomponente für rechts umfasst, die als (γ2 RS + δ2 RF) berechnet wird, wobei Rs das Surround-Signal für rechts kennzeichnet und RF das Signal für rechts vorne kennzeichnet und wobei γ2 größer ist als δ2.
     
    3. Signalverarbeitungsvorrichtung (6) nach Anspruch 1 oder 2, wobei die Simulationsfunktion für den linken Raum eine Simulationskomponente für den linken Raum und eine Soundstabilitätskomponente für links umfasst, wobei die Soundstabilitätskomponente für links das Signal (LF) für links vorne und das Surround-Signal (LS) für links als einen zusätzlichen Term umfasst, der mit einem entsprechenden Koeffizienten gewichtet wird, und wobei die Simulationskomponente für den linken Raum größer ist als die Soundstabilitätskomponente für links und wobei die Simulationsfunktion für den rechten Raum eine Simulationskomponente für den rechten Raum und eine Soundstabilitätskomponente für rechts umfasst, wobei die Soundstabilitätskomponente für rechts das Signal (RF) für rechts vorne und das Surround-Signal (RS) für rechts als einen zusätzlichen Term umfasst, der mit einem entsprechenden Koeffizienten gewichtet wird, und wobei die Simulationskomponente für den rechten Raum größer ist als die Soundstabilitätskomponente für rechts.
     
    4. Signalverarbeitungsvorrichtung (6) nach einem der vorhergehenden Ansprüche, wobei die Simulationsfunktionen für den linken und rechten Raum dazu ausgelegt sind, einen Hörraum zu simulieren, der größer ist als ein Innenraum eines Fahrzeugs.
     
    5. Signalverarbeitungsvorrichtung (6) nach einem der vorhergehenden Ansprüche, wobei das Raumsimulationsmodul (64) ferner eine Simulationsfunktion für den linken hinteren Raum, die ein 3D-Höhe-Signal (LR3D) für links hinten erzeugt, wobei das Signal (LF) für links vorne und das Surround-Signal (LS) für links Eingaben darin sind, und eine Simulationsfunktion für den rechten hinteren Raum, die ein 3D-Höhe-Signal (RR3D) für rechts hinten erzeugt, wobei das Signal (RF) für rechts vorne und das Surround-Signal (RS) für rechts Eingaben darin sind, umfasst.
     
    6. Signalverarbeitungsvorrichtung (6) nach einem der vorhergehenden Ansprüche, wobei das Mehrkanalaudiosignal ein Eingangssignal ist, das von einer Audioquelle stammt.
     
    7. Signalverarbeitungsvorrichtung (6) nach einem der Ansprüche 1 bis 5, wobei der Eingangssignalabschnitt (62) ein Audiosignalumwandlungsmodul (70) umfasst, wobei das Audiosignalumwandlungsmodul (70) dafür ausgebildet ist, das Mehrkanalaudiosignal aus einem Eingangssignal, dem mindestens eines des Signals für links vorne, des Surround-Signals für links, des Signals für rechts vorne und des Surround-Signals für rechts fehlt, wie z.B. aus einem zwei-Kanal-Stereo-Eingangssignal, zu erzeugen.
     
    8. Fahrzeug-Soundsystem (2), das eine Mehrzahl von Lautsprechern umfasst, wobei die Mehrzahl von Lautsprechern einen linken vorderen 3D-Lautsprecher (25) und einen rechten vorderen 3D-Lautsprecher (26) umfasst, wobei der linke vordere 3D-Lautsprecher (25) und der rechte vordere 3D-Lautsprecher (26) dazu ausgelegt sind, in einem oberen vorderen Teil eines Fahrzeugs (4) angeordnet zu sein,
    wobei das Fahrzeug-Soundsystem (2) ferner eine Signalverarbeitungsvorrichtung (6) nach einem der vorhergehenden Ansprüche umfasst, wobei die Signalverarbeitungsvorrichtung (6) mit dem linken vorderen 3D-Lautsprecher (25) und dem rechten vorderen 3D-Lautsprecher (26) für die Ausgabe des 3D-Höhe-Signals (LF3D) für links und des 3D-Höhe-Signals (RF3D) für rechts gekoppelt ist.
     
    9. Personenbeförderungsfahrzeug (4), wie ein Auto, Bus oder Lastwagen, das ein Fahrzeug-Soundsystem (2) nach Anspruch 8 umfasst, wobei das Fahrzeug-Soundsystem (2) so in dem Personenbeförderungsfahrzeug eingebaut ist, dass der linke vordere 3D-Lautsprecher (25) und der rechte vordere 3D-Lautsprecher (26) in einem oberen vorderen Teil des Personenbeförderungsfahrzeugs (4) angeordnet sind.
     
    10. Signalverarbeitungsverfahren für ein Fahrzeug-Soundsystem, wobei das Verfahren die Schritte umfasst von:

    Empfangen eines Mehrkanalaudiosignals, das mindestens ein Signal (LF) für links vorne, ein Surround-Signal (LS) für links, ein Signal (RF) für rechts vorne und ein Surround-Signal (RS) für rechts umfasst, wobei

    das Signalverarbeitungsverfahren ferner die Schritte umfasst von:

    Erzeugen mindestens eines 3D-Höhe-Signals (LF3D) für links und eines 3D-Höhe-Signals (RF3D) für rechts zum Bereitstellen einer Raumsimulation durch das Fahrzeug-Soundsystem, wobei das Signal (LF) für links vorne und das Surround-Signal (LS) für links Eingaben in eine Simulationsfunktion für einen linken Raum sind, die das 3D-Höhe-Signal (LF3D) für links erzeugt, und wobei das Signal (RF) für rechts vorne und das Surround-Signal (RS) für rechts Eingaben in eine Simulationsfunktion für einen rechten Raum sind, die das 3D-Höhe-Signal (RF3D) für rechts erzeugt,

    wobei die Simulationsfunktion für den linken Raum eine Simulationsfunktion für den linken vorderen Raum ist, wobei die Simulationsfunktion für den rechten Raum eine Simulationsfunktion für den rechten vorderen Raum ist, wobei das 3D-Höhe-Signal (LF3D) für links ein 3D-Höhensignal für links vorne ist und wobei das 3D-Höhe-Signal (RF3D) für rechts ein 3D-Höhensignal für rechts vorne ist, und

    wobei die Simulationsfunktion für den linken Raum eine Simulationskomponente für den linken Ram umfasst, die als f11 LS + β1 LF) berechnet wird, wobei LS das Surround-Signal für links kennzeichnet und LF das Signal für links vorne kennzeichnet und wobei α1 größer ist als β1 und wobei die Simulationsfunktion für den rechten Raum eine Simulationskomponente für den rechten Raum umfasst, die als f22 RS + β2 RF) berechnet wird, wobei Rs das Surround-Signal für rechts kennzeichnet und RF das Signal für rechts vorne kennzeichnet und wobei α2 größer ist als β2,

    und

    Ausgeben des 3D-Höhe-Signals (LF3D) für links und 3D-Höhe-Signals (RF3D) für rechts an einen linken 3D-Lautsprecher (25) und einen rechten 3D-Lautsprecher (26), die in einem oberen vorderen Teil eines Fahrzeugs angeordnet sind.


     


    Revendications

    1. Appareil de traitement de signaux (6) pour un système audio (2) destiné à un véhicule, comprenant :

    une partie (62) réservée à l'entrée des signaux, par l'intermédiaire de laquelle, en état de marche, un signal audio à canaux multiples est produit, le signal audio à canaux multiples comprenant au moins un signal avant gauche (LF), un signal d'ambiance gauche (LS), un signal avant droit (RF) et un signal d'ambiance droit (Rs) ;

    dans lequel l'appareil de traitement de signaux (6) comprend en outre :

    un module de simulation acoustique de salle (64) conçu pour recevoir le signal audio à canaux multiples et pour générer au moins un signal de hauteur gauche en 3D (LF3D) et un signal de hauteur droit en 3D (RF3D), le module de simulation acoustique de salle (64) comprenant une fonction de simulation acoustique de salle gauche générant le signal de hauteur gauche en 3D (LF3D), le signal avant gauche (LF) et le signal d'ambiance gauche (LS) y représentant des entrées, et une fonction de simulation acoustique de salle droite générant le signal de hauteur droit en 3D (RF3D), le signal avant droit (RF) et le signal d'ambiance droit (RS) y représentant des entrées ;

    dans lequel la fonction de simulation acoustique de salle gauche représente une fonction de simulation acoustique de salle avant gauche ; dans lequel la fonction de simulation acoustique de salle droite représente une fonction de simulation acoustique de salle avant droite ; dans lequel le signal de hauteur gauche en 3D (LF3D) représente un signal de hauteur avant gauche en 3D et le signal de hauteur droit en 3D (RF3D) représente un signal de hauteur avant droit en 3D ; et

    dans lequel la fonction de simulation acoustique de salle gauche comprend une composante de simulation acoustique de salle gauche calculée sous la forme f11 LS + β1 LF), LS désignant le signal d'ambiance gauche et LF désignant le signal avant gauche, et α1 étant supérieur à β1 ; et dans lequel la fonction de simulation acoustique de salle droite comprend une composante de simulation acoustique de salle droite calculée sous la forme f2(a2 RS + β2 RF), Rs désignant le signal d'ambiance droit et RF désignant le signal avant droit, et α2 étant supérieur à β2 ; et une partie (66) réservée à la sortie des signaux, destinée à envoyer le signal de hauteur gauche en 3D (LF3D) et le signal de hauteur droit en 3D (RF3D) à un haut-parleur gauche en 3D (25) et à un haut-parleur droit en 3D (26) disposés dans une partie supérieure avant d'un véhicule.


     
    2. Appareil de traitement de signaux (6) selon la revendication 1, dans lequel la fonction de simulation acoustique de salle gauche comprend une composante de stabilité audio gauche calculée sous la forme (γ1 Ls + δ1 LF), Ls désignant le signal d'ambiance gauche et LF désignant le signal avant gauche, et γ1 étant supérieur à δ1 ; et dans lequel la fonction de simulation acoustique de salle droite comprend une composante de stabilité audio droite calculée sous la forme (γ2 RS + δ2 RF), RS désignant le signal d'ambiance droit et RF désignant le signal avant droit, et γ2 étant supérieur à δ2.
     
    3. Appareil de traitement de signaux (6) selon la revendication 1 ou 2, dans lequel la fonction de simulation acoustique de salle gauche comprend une composante de simulation acoustique de salle gauche et une composante de stabilité audio gauche, la composante de stabilité audio gauche comprenant le signal avant gauche (LF) et le signal d'ambiance gauche (LS) sous la forme d'un terme additif, pondérés par l'intermédiaire d'un coefficient respectif, et la composante de simulation acoustique de salle gauche étant supérieure à la composante de stabilité audio gauche, et dans lequel la fonction de simulation acoustique de salle droite comprend une composante de simulation acoustique de salle droite et une composante de stabilité audio droite, la composante de stabilité audio droite comprenant le signal avant droit (RF) et le signal d'ambiance droit (RS) sous la forme d'un terme additif, pondérés par l'intermédiaire d'un coefficient respectif, et la composante de simulation acoustique de salle droite étant supérieure à la composante de stabilité audio droite.
     
    4. Appareil de traitement de signaux (6) selon l'une quelconque des revendications précédentes, dans lequel les fonctions de simulation acoustique de salle gauche et droite sont configurées pour simuler un espace auditif qui est plus grand qu'un habitacle de véhicule.
     
    5. Appareil de traitement de signaux (6) selon l'une quelconque des revendications précédentes, dans lequel le module de simulation acoustique de salle (64) comprend en outre une fonction de simulation acoustique de salle arrière gauche générant un signal de hauteur arrière gauche en 3D (LR3D), le signal avant gauche (LF) et le signal d'ambiance gauche (LS) y représentant des entrées, et une fonction de simulation acoustique de salle arrière droite générant un signal de hauteur arrière droit en 3D (RR3D), le signal avant droit (RF) et le signal d'ambiance droit (RS) y représentant des entrées.
     
    6. Appareil de traitement de signaux (6) selon l'une quelconque des revendications précédentes, dans lequel le signal audio à canaux multiples représente un signal d'entrée qui émane d'une source audio.
     
    7. Appareil de traitement de signaux (6) selon l'une quelconque des revendications 1 à 5, dans lequel la partie (62) réservée à l'entrée des signaux comprend un module de conversion de signaux audio (70), le module de conversion de signaux audio (70) étant conçu pour générer le signal audio à canaux multiples à partir d'un signal d'entrée dans lequel ne figure pas au moins un signal choisi parmi le signal avant gauche, le signal d'ambiance gauche, le signal avant droit et le signal d'ambiance droit, comme par exemple à partir d'un signal d'entrée stéréo à deux canaux.
     
    8. Système audio (2) destiné à un véhicule comprenant un certain nombre de haut-parleurs, lesdits plusieurs haut-parleurs comprenant un haut-parleur avant gauche en 3D (25) et un haut-parleur avant droit en 3D (26), le haut-parleur avant gauche en 3D (25) et le haut-parleur avant droit en 3D (26) étant configurés pour venir se disposer dans une partie supérieure avant d'un véhicule (4) ;
    le système audio (2) destiné à un véhicule comprenant en outre un appareil de traitement de signaux (6) selon l'une quelconque des revendications précédentes, l'appareil de traitement de signaux (6) étant couplé au haut-parleur avant gauche en 3D (25) et au haut-parleur avant droit en 3D (26) pour la production du signal de hauteur gauche en 3D (LF3D) et du signal de hauteur droite en 3D (RF3D) aux haut-parleurs en question.
     
    9. Véhicule (4) destiné au transport de passagers, tel qu'un car, un bus ou une camionnette, comprenant un système audio (2) destiné à un véhicule selon la revendication 8, le système audio (2) destiné à un véhicule étend monté dans le véhicule destiné au transport de passagers, le haut-parleur avant gauche en 3D (25) et le haut-parleur avant droit en 3D (26) étant disposés dans une partie supérieure avant du véhicule (4) destiné au transport des passagers.
     
    10. Procédé de traitement de signaux pour un système audio destiné à un véhicule, le procédé comprenant l'étape consistant à

    recevoir un signal audio à canaux multiples comprenant au moins un signal avant gauche (LS), un signal d'ambiance gauche (LS), un signal avant droit (RF) et un signal d'ambiance droit (RS) ;

    dans lequel le procédé de traitement de signaux comprend en outre les étapes consistant à :

    générer au moins un signal de hauteur gauche en 3D (LF3D) et un signal de hauteur droit en 3D (RF3D) dans le but d'obtenir une simulation acoustique de salle par l'intermédiaire du système audio destiné à un véhicule, le signal avant gauche (LF) et le signal d'ambiance gauche (Ls) représentant des entrées dans une fonction de simulation acoustique de salle gauche qui génère le signal de hauteur gauche en 3D (LF3D), et le signal avant droit (RF) et le signal d'ambiance droit (RS) représentant des entrées dans une fonction de simulation acoustique de salle droite qui génère le signal de hauteur droit en 3D (RF3D) ;

    dans lequel la fonction de simulation acoustique de salle gauche représente une fonction de simulation acoustique de salle avant gauche, dans lequel la fonction de simulation acoustique de salle droite représente une fonction de simulation acoustique de salle avant droite, dans lequel le signal de hauteur gauche en 3D représente un signal de hauteur avant gauche en 3D et dans lequel le signal de hauteur droite en 3D représente un signal de hauteur avant droit en 3D ; et

    dans lequel la fonction de simulation acoustique de salle gauche comprend une composante de simulation acoustique de salle gauche calculée sous la forme f11 Ls + β1 LF), Ls désignant le signal d'ambiance gauche et LF désignant le signal avant gauche, et α1 étant supérieur à β1 ; et dans lequel la fonction de simulation acoustique de salle droite comprend une composante de simulation acoustique de salle droite calculée sous la forme f2(a2 RS + β2 RF), RS désignant le signal d'ambiance droit et RF désignant le signal avant droit, et α2 étant supérieur à β2 ; et

    envoyer le signal de hauteur gauche en 3D (LF3D) et le signal de hauteur droit en 3D (RF3D) à un haut-parleur gauche en 3D (25) et un haut-parleur droit en 3D (26) disposés dans une partie supérieure avant d'un véhicule.


     




    Drawing









    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description