WO2019175347A1

WO2019175347A1 - Device and method for defining at least one private acoustic area in the passenger compartment of a vehicle

Info

Publication number: WO2019175347A1
Application number: PCT/EP2019/056484
Authority: WO
Inventors: Laurent LANCERICA; Patrice Bertrand; Thierry GIACCONE; Christophe Comps
Original assignee: Renault S.A.S
Priority date: 2018-03-14
Filing date: 2019-03-14
Publication date: 2019-09-19
Also published as: FR3078931B1; FR3078931A1

Abstract

The invention relates to a device for defining at least one private acoustic area in the passenger compartment of a vehicle, comprising: - a plurality of reception elements (M1, M2, M3, M4, M5, M6, M7, M8, M9, M10, M11, M12) for receiving at least one initial audio signal, distributed in the passenger compartment of the vehicle, - at least one audio emission element (HP1, HP2, HP3, HP3, HP4, HP5, HP6, HP7, HP8, HP9, HP10, HP10, HP11, HP12) designed to emit an attenuating audio signal in an area of the passenger compartment outside of the first private acoustic area, and - a control unit programmed to a) receive and process information relating to each initial audio signal transmitted by said reception elements, in order to identify an emission location of this initial audio signal, b) determine, on the basis of each initial audio signal and its emission location, said attenuating audio signal such that, in at least part of the area of the passenger compartment outside of the private acoustic area, the amplitude of the overall audio signal resulting from the superimposition of each initial audio signal and of the attenuating audio signal is less than the amplitude of said initial audio signal, and c) command the emission of this attenuating audio signal by said at least one audio emission element.

Description

DEVICE AND METHOD FOR THE ARRANGEMENT OF AT LEAST ONE ACOUSTIC ZONE

PRIVATE IN THE COCKPIT OF A VEHICLE

TECHNICAL FIELD TO WHICH THE INVENTION REFERS

The present invention relates to a device and a method for the arrangement of at least one private acoustic zone in the passenger compartment of a vehicle.

BACKGROUND

Devices and methods are known for limiting the amplitude of engine sounds heard by the passengers of a vehicle.

To do so, means for receiving engine noise are arranged near the noisy elements of the engine. All the noises received by these reception means are then attenuated by the emission, throughout the cabin, of a sound signal adapted to interfere with the engine noise to limit their amplitude to a position of given observation of the cabin.

These devices and methods limit the ambient noise of the engine in the passenger compartment and provides greater comfort to the passengers of the vehicle. On the other hand, they do not make it possible to select a particular sound signal from the detected noise in order to limit the amplitude thereof in a specific area of the vehicle.

It is therefore not possible to selectively attenuate certain sound signals in a part of the passenger compartment.

OBJECT OF THE INVENTION

In order to overcome the aforementioned drawback of the state of the art, the present invention proposes a device for selectively attenuating a sound signal in a part of the passenger compartment of the vehicle.

More particularly, there is provided according to the invention a device for the arrangement of at least one private acoustic zone in the passenger compartment of a vehicle, comprising:

a plurality of elements for receiving at least one initial sound signal, distributed in the passenger compartment of the vehicle, at least one sound emission element adapted to emit an attenuation sound signal in an area of the passenger compartment external to the first private acoustic zone, and

- a control unit programmed for

a) receive and process information relating to each initial sound signal transmitted by said reception elements, to identify a place of emission of this initial sound signal,

b) determine, according to each initial sound signal and its place of emission, said attenuation sound signal so that, in at least a part of the zone of the passenger compartment outside the private acoustic zone, the amplitude of the overall sound signal resulting from the superimposition of each initial sound signal and the attenuation sound signal is less than the amplitude of the initial sound signal and

c) controlling the emission of this attenuation sound signal by said at least one sound emission element.

This device allows the development of a private acoustic zone in the passenger compartment of the vehicle.

At least part of all the sound signals emitted in this private acoustic zone is attenuated in the rest of the passenger compartment so that only the passenger or passengers of the vehicle sitting in the private acoustic zone hear this part of the passenger compartment. set of sound signals emitted in this private acoustic zone.

Thanks to the device according to the invention, the sound signals emitted in the private acoustic zone can be attenuated in the rest of the passenger compartment selectively, according to their place of emission.

The private acoustic zone preferably surrounds one or more seats of the vehicle.

Thus, it will be possible for example to attenuate outside the private acoustic zone the vocal sound signals emitted by the passengers sitting in this zone, so that their discussions remain private. It will also be possible to selectively attenuate, in the rest of the cabin, the music emitted in the private acoustic zone by a multimedia system of the vehicle so that only the passengers sitting in the private acoustic zone hear this music . Passengers sitting in the private acoustic zone can enjoy their conversations and music in complete peace of mind, knowing that passengers in other areas will not be able to hear these conversations or music.

Other nonlimiting and advantageous features of the device according to the invention, taken individually or in any technically possible combination, are as follows:

in step a), the control unit is also programmed to determine a direction of propagation of each initial sound signal;

said control unit is programmed to compare, in step a), the information relating to each initial sound signal transmitted by each reception element of said plurality of reception elements in order to deduce the place of emission of this signal initial sound;

said information relating to each initial sound signal comprises at least its phase and / or its time delay and / or its amplitude;

said control unit is programmed to determine, in step b), the attenuation sound signal so that the phase of this attenuation sound signal is in phase opposition with respect to the sum of each signal initial sound in that part of the cockpit area outside the private acoustic zone;

a plurality of sound emission elements are provided, and the control unit is programmed to, in step c), control the emission of the attenuation sound signal by a part of the plurality of elements. sound emission determined according to the direction of propagation of each initial sound signal;

the control unit is programmed, in step c), to command the emission of the attenuation sound signal intended to attenuate the same initial sound signal by at least two sound emission elements;

said control unit is further programmed to determine, as a function of the initial sound signal and of its place of emission, an amplification sound signal so that this amplification sound signal is in phase with the sound signal. initially in a part of the private acoustic zone and to control the emission of this amplification sound signal;

- for the arrangement of a plurality of private acoustic zones in the passenger compartment of the vehicle, the device comprises said private acoustic zone and at least one additional private acoustic zone, in which at least one additional sound emission element is provided with an additional attenuation sound signal in a zone of the external cabin to the additional private acoustic zone, and wherein said control unit is programmed to, in step b), determine, according to each initial sound signal and its place of emission, said audible signal of additional attenuation such that, in the area of the passenger compartment outside the additional private acoustic zone, the amplitude of the overall sound signal resulting from the superposition of each initial sound signal and the additional attenuation sound signal is less than the amplitude of said initial sound signal and, in step c), controlling the emission of this additional attenuation sound signal by said element of sound. additional sound mission.

The invention also relates to a method of arranging at least one private acoustic zone in the passenger compartment of a vehicle comprising the following steps:

receiving at least one initial sound signal by a plurality of reception elements,

- determination of the place of emission of each initial sound signal,

determination, according to each initial sound signal and its place of emission, of an attenuation sound signal such that, in at least a part of the zone of the passenger compartment external to the private acoustic zone, the amplitude of the overall sound signal resulting from the superimposition of each initial sound signal and the attenuation sound signal is less than the amplitude of the initial sound signal and

- emission of this attenuation sound signal in the zone of the passenger compartment outside the private acoustic zone.

Finally, the invention relates to a motor vehicle comprising at least one device according to one of the preceding claims, providing at least one private acoustic zone in the passenger compartment of the vehicle.

DETAILED DESCRIPTION OF AN EXEMPLARY EMBODIMENT

The following description with reference to the accompanying drawings, given as non-limiting examples, will make it clear what the invention consists of and how it can be achieved.

In the accompanying drawings, the single figure is a schematic view of the above the passenger compartment of a vehicle according to the invention.

In the single figure, there is shown schematically the passenger compartment 100 of a vehicle according to the invention, equipped with a device for arranging a plurality of private acoustic zones.

This is for example a motor vehicle of a particular. Of course, it may also be a variant of a vehicle for public transport, or air, river or sea.

This passenger compartment 100 is delimited by side walls 100A formed here by the doors of the vehicle, at the front by a front wall 100B comprising the dashboard 101 and the front windshield, at the rear by a rear wall 100C comprising the rear windshield and through the roof and floor of the vehicle. Diagram 102 is shown schematically at the front of the passenger compartment 100.

In the example shown, the passenger compartment 100 here comprises four seats defining four seats: the seats 103 front left and seat 104 front right are individual seats while the seats 105, 106 rear left and right rear are part of a seat 107. Each seat 103, 104, 105, 106 is provided with a headrest 103A, 104A, 105A, 106A.

Four seats are thus defined in the cockpit, to accommodate four seated passengers. The head of each passenger sitting in the passenger compartment is in the usual manner near the headrest 103A, 104A, 105A, 106A of the seat on which it sits.

The vehicle is here equipped with a device for the development of at least one private acoustic zone in the passenger compartment 100, according to the invention.

In general, the device according to the invention is intended to allow the development of a number of private acoustic zones less than or equal to the maximum number of seats of the vehicle.

The private acoustic zones may have a fixed range, predetermined for example during the installation of the device according to the invention, or have a variable extent that passengers can adjust according to their needs, as explained below.

In the example described here, the device according to the invention authorizes the fitting of a number of adjustable private acoustic zones comprised between one and four private acoustic zones.

Each private acoustic zone is preferably located around one or several seats of the vehicle, that is to say around one or more seats.

More specifically, the device according to the invention comprises:

a plurality of receiving elements M1, M2, M3, M4, M5, M6, M7, M8, M9, M10, M11, M12 of a sound signal, distributed in the passenger compartment 100 of the vehicle, and

at least one transmission element HP1, HP2, HP3, HP4, HP5, HP6, HP7, HP8, HP9, HP10, HP11, HP12 of a sound attenuation signal

and a control unit (not shown) adapted to communicate with the reception and transmission elements.

The control unit can be integrated into the on-board computer of the vehicle.

Said private acoustic zone being located around at least one of the seats 103, 104, 105, 106 of the vehicle, said receiving elements comprise at least one receiving element positioned in the private acoustic zone and a receiving element positioned at the outside the private acoustic zone and there is provided a number of sound emission elements at least equal to the number of seats included in the private acoustic zone.

The receiving elements M1, M2, M3, M4, M5, M6, M7, M8, M9, M10, M11, M12 are for example microphones shown schematically in the single figure by circles.

Each microphone can be single or dual, depending on whether they have one or two preferred receiving directions.

The single microphones M2, M4, M5, M6, M7, M9, M11 have a preferred reception direction oriented either towards the front of the vehicle or toward the rear of the vehicle, while the double microphones M1, M2, M3, M8 , M10, M12, represented by a crossed circle, have two preferred reception directions oriented towards the front and towards the rear of the vehicle. Double microphones are equivalent to two single microphones placed back-to-back.

The reception elements are distributed in the passenger compartment so as to efficiently receive the sound signals emitted in all the private acoustic zones defined in the passenger compartment 100.

When the device according to the invention fits only one private acoustic zone, preferably at least one receiving element is provided in the private acoustic zone and a receiving element outside this zone is provided. zoned. When several distinct private acoustic zones are provided by the device, preferably at least one receiving element is provided in each private acoustic zone.

In general, the distribution of the receiving elements and their positions are determined according to an acoustic model of the passenger compartment of the vehicle.

Such an acoustic model is determined according to methods known to those skilled in the art.

The acoustic model of the passenger compartment makes it possible in particular to determine the propagation of a sound signal in the passenger compartment according to its place of emission, as well as to determine the main reflections of this sound signal and their propagation in the passenger compartment.

The acoustic model of the passenger compartment similar to that shown in the single figure shows in particular a central longitudinal propagation direction along the front-rear axis of the vehicle passing between the front and rear seats, two directions of lateral longitudinal propagation between the side walls. and the seats and two transverse forward and rearward propagation directions passing in front of each pair of front and rear seats. We will speak in the suite of longitudinal and transverse sound transmission corridors.

The acoustic model modeling the propagation of sounds in the passenger compartment is constantly updated according to the number of occupants in the car (by weight detection on the seat or camera for example) and by the analysis of the propagation of sound signals in the vehicle. This analysis can also be provided and used by multimedia and telephony bodies to serve as a basis for echo cancellations and other algorithms that optimize the distribution of sound contents in the cabin.

The receiving elements M1, M2, M3, M4, M5, M6, M7, M8, M9, M10, M11, M12 are preferably located in height in the passenger compartment 100, preferably above the seating surface of the seats 103, 104 and the bench 107. They are preferably located at a height close to that of the head of the passengers when they sit on the seats 103, 104 and the seat 107, and / or near the roof of the vehicle .

Thus, the effect of non-intrinsic obstacles to the vehicle, for example the bodies of passengers, on the propagation of sound signals, and therefore their reception by the receiving elements is limited.

It is preferably provided at least one main receiving element disposed opposite each seat of the vehicle, that is to say here in front of the back of each seat 103, 104, 105, 106, with at least one direction reception preferred oriented towards the back of this seat, that is to say toward the rear of the vehicle.

More specifically, these main receiving elements are preferably arranged in front of each headrest 103A, 104A, 105A, 106A of the vehicle. Here, the main microphones M1, M3, M6, M7 are placed so that they are in front of each passenger at the height of the face, when the passengers are sitting on the seats 103, 104, 105, 106. These In this way, the main reception elements receive very effectively the sound signals emitted in each corresponding private acoustic zone, in particular the voice of each passenger sitting on the corresponding seat.

These main reception elements are thus separated from the longitudinal sound transmission corridors: left and right lane between the doors and the seats, central corridor between the seats 103, 104 at the front and between the seats 105, 106 of the seat 107 to the rear.

They are also distant from the parts of the passenger compartment below the level of the glass surfaces (windows and windshields) which receive numerous reflections of sound signals on the walls of the passenger compartment, and in particular on the reflecting glass surfaces. importantly the sound signals.

The seats 103, 104 and the seat 107 of the vehicle tend to absorb sound signals.

The main microphones M1, M3 arranged at the front are double and have a preferred reception direction oriented towards the front and rear of the vehicle: they receive on one side the voice of the passenger sitting on the seat 103, 104 facing the back of the microphone and the sound of the engine and the sound signals reflected on the front wall of the cabin (dashboard and windshield) thanks to the part of the microphone facing forward.

The M6, M7 main microphones at the rear are simple, and their preferred reception direction is oriented towards the rear of the vehicle. Central secondary receiving elements, here the central secondary microphones M2 and M10 are arranged between the seats 103, 104 before and between the seats 105, 106 of the seat 107. They receive sound signals and reflections of sound signals propagating in the central longitudinal transmission corridor of the vehicle, mainly from the rear for the secondary microphone M10 and from the front for the secondary microphone M2. The central secondary microphones M2 and M10 are double.

Lateral side receiving elements, here the lateral secondary microphones M8 and M12, are arranged between the rear doors of the vehicle and the bench 107.

Finally, there is preferably a control receiving element M4, M5, M9, M11 located near the usual position of the head of each passenger, that is to say for example near each headrest 103A, 104A, 105A, 106A of the vehicle. The role of these control receiving elements will be explained later.

In addition, more specifically, the arrangement of the microphones in the passenger compartment of the vehicle here makes it possible, by mechanical and acoustic construction, to ensure that:

- any audible signal coming from the rear of the passenger compartment reaches the part of the secondary secondary microphone M2 facing towards the rear of the vehicle before reaching the ears of the passengers sitting on the seats 103, 104 before,

- any sound signal coming from the front of the passenger compartment, for example the engine, or reflected on the front wall of the passenger compartment, arrives at the part of the secondary secondary microphone M2 facing forward before reaching the ears passengers sitting on seats 103, 104 before,

- any audible signal coming from the front of the cabin arrives at the part of the central or lateral secondary microphones M8, M10, M12 facing forward before reaching the ears of the passengers sitting on the back seat 107,

- any audible signal coming from the rear, for example signals reflected on the rear wall of the passenger compartment, arrives at the part of the central or lateral secondary microphones M8, M10, M12 facing towards the rear before reaching the ears passengers sitting on the back seat.

There is provided here a plurality of sound emission elements HP1 to HP12. he This is speakers. They are represented schematically in the single figure by triangles associated with a sign representing a sound wave and its overall direction of emission.

The device according to the invention preferably comprises at least one sound emission element associated with each private acoustic zone.

Here, there is provided a longitudinal transmission element HP1, HP2, HP7, HP8 disposed in front of each seat of the vehicle, that is to say in front of each seat 103, 104 before and each seat 105, 106 rear of the bench 107.

The front speakers HP1, HP2 arranged opposite the seats 103, 104 are for example mounted on the dashboard of the vehicle. The rear speakers HP7, HP8 arranged opposite the seats 105, 106 of the seat 107 are for example mounted on the back of the seats 103, 104 before, in the headrests of these seats.

These front and rear speakers HP1, HP2, HP7, HP8 emit in a longitudinal direction, towards the rear, and will therefore be particularly suitable for emitting an attenuation sound signal to attenuate an initial sound signal emitted forwards, in a direction of propagation close to the longitudinal direction.

The angular range of the directions of propagation that can be canceled varies according to the loudspeakers, which may have an emission range of between about 20 ° and 180 °.

In addition, the sound waves emitted by the loudspeaker are different in front of the loudspeaker and at the limits of the angular emission range: the waves emitted at +/- 80 ^° with respect to the longitudinal axis of emission by example will be "curves" near the loudspeaker, while those emitted opposite, along the longitudinal axis, will first plan and then become curved farther from the speaker. The capabilities of the loudspeaker to emit the attenuation sound signal that best approximates the characteristics of the signal in phase opposition with respect to the initial sound signal, even if the speaker is not in the exact axis the propagation direction of the initial sound signal are also taken into account.

Two mixed sound emitting elements, that is to say here side speakers HP3, HP4, HP5, HP6, HP9, HP10, HP11, HP12 are also arranged laterally in each headrest 103A, 104A, 105A, 106A seats 103, 104, 105, 106, one located on the right side of the headrest and the other on the left. These side speakers emit in a diagonal direction forward, having a longitudinal component and a transverse component and will therefore be adapted to emit an attenuation sound signal to attenuate the longitudinal and transverse components of an initial sound signal transmitted to the rear.

One can also consider fixing the speakers on the roof of the vehicle, with a direction of emission oriented roof to the floor of the vehicle.

In general, the receiving elements are positioned behind the sound emission elements, in order to minimize the reception of the direct sound signals emitted by the sound emission elements.

This reception of the direct sound signals emitted by the transmission elements can also be compensated by digital processing of the sound signals received by the reception elements, which is carried out by the control unit.

All or part of the reception and / or sound transmission elements may also be part of the vehicle's multimedia system, used for example for wireless telephone calls or listening to music.

The reception and sound emission elements of the example described and shown here make it possible to define a number of private acoustic zones comprised between one and four.

The control unit of the device according to the invention is furthermore programmed to:

a) receive and process information relating to an initial sound signal transmitted by said reception elements, to deduce the place of emission of this initial sound signal,

b) determining, according to said initial sound signal and its place of emission, an attenuation sound signal so that, in the zone of the passenger compartment outside one of said private acoustic zones, the amplitude of the signal overall sound resulting from the superimposition of the initial sound signal and the attenuation sound signal is less than the amplitude of the initial sound signal and c) control the emission of this attenuation sound signal by one said sound emission elements adapted to emit the attenuation sound signal outside said private acoustic zone.

Preferably, in step a), the control unit is also programmed to derive information relating to the initial sound signal the direction of propagation of this signal and / or its multiple reflections on the walls of the vehicle and on unknown obstacles the acoustic model, linked for example to the bulky objects of the passenger compartment: parcels, clothes, variability of the size and the corpulence of the passengers ...

Preferably, in step b), the control unit also takes into account the acoustic model of the passenger compartment, which corresponds to a propagation model of the sound signal calculated in the vehicle.

The role of the attenuation sound signal is more precisely to sufficiently attenuate the initial sound signal so that this initial sound signal is not perceived by other passengers.

This objective is for example achieved by a reduction of about 20 decibels in the amplitude of the initial sound signal. One can also consider dividing by a coefficient between 10 and 100 the amplitude of the initial sound signal.

This device allows the implementation of the method of fitting at least one private acoustic zone in the passenger compartment of the vehicle according to the invention, which comprises the following steps:

reception of an initial sound signal by said reception elements,

- determination of the place of emission of this initial sound signal,

determination, as a function of said initial sound signal and of its place of emission, of an attenuation sound signal so that, in the zone of the passenger compartment external to one of the private acoustic zones, the amplitude of the overall sound signal resulting from the superposition of the initial sound signal and the attenuation sound signal is less than the amplitude of the initial sound signal and

emission of this attenuation sound signal in the zone of the passenger compartment outside this private acoustic zone.

As previously mentioned, the private acoustic zones, their number, position and extent can be fixed in advance by construction or can be modulated.

Preferably, the number of private acoustic zones and the geometry of these zones is flexible according to the needs of the passengers. The control unit then comprises a control interface allowing one or more passengers, for example the driver or the passengers before or each passenger, to indicate to the control unit how to configure each private acoustic zone associated with a or more seats in the cockpit. More specifically, it is possible, for each private acoustic zone that can be defined, to indicate to the central unit whether it should be activated or not, that is to say acoustically isolated from each other private acoustic zone and / or from the rest of the cabin.

In practice, in the example described here, there is a maximum of four individual private acoustic zones, that is to say surrounding a single passenger. Each passenger can therefore activate the private acoustic zone in which he sits for example to telephone without disturbing other passengers or without his conversation being heard by other passengers.

This is achieved by pressing a button or using for example a voice command.

It is also possible to indicate to the control unit that several of the individual private acoustic zones, here two or three, must be grouped together to form a single private acoustic zone allowing a discreet conversation between the passengers of these two or three grouped zones. .

This is done in a step prior to the implementation of the steps described above, which takes place as soon as at least one private acoustic zone is activated.

During the implementation of the device according to the invention, an initial sound signal emitted into the passenger compartment is received by all the receiving elements. The source of this sound signal may be located inside or outside the passenger compartment. The sound sources located inside the passenger compartment include the passengers (their voices) and the multimedia system. The sound sources located outside include the engine that emits a motor noise in the cabin overall through the front wall of the cabin.

The receiving elements, here the microphones M1 to M12, receive said initial sound signal. This initial beep is converted into an electrical signal by each microphone. Each electrical signal constitutes a set of data relating to the initial sound signal received by each reception element, at least a portion of which is transmitted to the control unit by each receiving element.

The control unit therefore receives a portion of the data relating to the initial sound signal received by each receiving element.

These data comprise at least one information on the phase and / or the time delay and / or the amplitude of the initial sound signal received by the corresponding reception element.

The phase of the initial sound signal indicates its instantaneous situation in a period, the initial sound signal being periodic.

The initial sound signal arrives at a distant remote microphone. Time delay is the time taken by the signal to propagate from the source that emitted it to the receiver that received it.

The control unit is programmed to analyze the phase shift of this initial sound signal when it arrives at each reception element, to deduce the place of emission of this initial sound signal: the initial sound signal will arrive later on an element reception more distant from its place of emission than on a receiving element closer to its place of emission. It is then a question here of comparing the phase of the initial sound signal received by each reception element.

This analysis is performed on the basis of an algorithm taking into account the location of each receiving element, the emission elements, the vehicle sound characteristics and acoustics of the cabin, including the acoustic model of the passenger compartment. This analysis makes it possible to separate the different components of the initial sound signal received, and to determine the place of emission of each of its components. This algorithm is in particular used by hands-free telephony systems, in order to cancel the echo sent back by the loudspeakers to the remote user via the telephone microphone. In these telephony systems, the emitted sound signal and its source of emission are known; echo estimation is usually done by a single microphone, and in some systems two microphones can be used to better estimate residual echoes (reflections on walls in an enclosed space for example). This algorithm is known to those skilled in the art and is not the subject of the present invention. It will not be described in more detail here.

The control unit is here programmed to take into account the amplitude of this initial sound signal when it arrives on each reception element, to deduce therefrom the place of emission of this initial sound signal: the amplitude of the initial sound signal is all the greater as the element of reception is closer to the place of emission.

When a plurality of initial sound signals are detected by the receiving elements, the control unit is programmed to

receiving and processing information relating to each initial sound signal to identify a place of emission of this initial sound signal: the place of emission of each initial sound signal is thus determined;

determining, according to each initial sound signal and its place of emission, said attenuation sound signal so that, in at least a part of the zone of the passenger compartment outside the private acoustic zone, the amplitude the overall sound signal resulting from the superposition of each initial sound signal and the attenuation sound signal is smaller than the amplitude of said initial sound signal; and

- Control the emission of this attenuation sound signal by said at least one sound emission element.

In practice, in step b), the attenuation sound signal is determined to be in phase opposition with respect to the sum of each initial sound signal in said part of the cabin area outside the private acoustic zone. as will be exemplified later.

It is subsequently considered that the initial sound signal comes from a single place of emission.

Here, determining the place of emission of the initial sound signal is to identify the source of this initial sound signal: if the place of emission of the initial sound signal is located near the head of one of the passengers, it is is the voice of one of the passengers: if the place of emission is located at the front of the vehicle it is a noise of the engine.

The control unit is then programmed to determine the attenuation sound signal according to the initial sound signal and its place of emission.

In particular, the device according to the invention aims to reduce or even cancel the sound of the voice of the passengers located in the private acoustic zone defined for the passengers located in the rest of the cabin.

Thus, the control unit is programmed to determine the signal sound attenuation based on the initial sound signal whose place of emission is located in certain parts of the private acoustic zone, which correspond for example to the usual position of the head of the passenger (s) sitting in this private acoustic zone, for that, in the zone of the passenger compartment outside the private acoustic zone, the amplitude of the overall sound signal resulting from the superposition of the initial sound signal and the attenuation sound signal is less than the amplitude of the initial sound signal. The attenuation sound signal may also be determined when the emission location is situated in other parts of the private acoustic zone, which correspond, for example, to the position of the speakers of the multimedia system or to a front part of the vehicle. including the engine.

In addition, the control unit can be programmed to take into account known sources of noise emissions from the vehicle: for example a multimedia content or a conversation via the vehicle telephone system and whose sound is broadcast by the systems of the vehicle. emission of the vehicle. In this case, the position of the sound source is known and its propagation mode is predetermined. The sound signal emitted by each known sound emission source, its mode of diffusion and its propagation in the cabin are predetermined or obtained directly by the control unit. The control unit can thus directly receive the information concerning the initial sound signal emitted by these known sound emission sources. The control unit can first analyze these initial sound signals.

The signal received and transmitted by the receiving elements and corresponding to the initial signals emitted by these known sound emission sources can be used to refine the acoustic model of the cabin.

The signal received by the reception elements and corresponding to the initial signals emitted by these known sound emission sources is used when the acoustic model is modified, for example by obstacles in the car.

For the other sound sources, not known because not belonging to the vehicle for example, preferably, the determination of the attenuation sound signal takes into account the initial sound signal received by the reception element for which this initial sound signal presents the greatest amplitude.

For this purpose, the control unit determines whether the place of emission determined is located in a predetermined part of the private acoustic zone for which the initial sound signal must be attenuated outside the private acoustic zone. For example, in the case of attenuating passengers 'voices outside the private acoustic zone, only sound signals with a place of emission close to the passengers' heads are attenuated.

The determination of the attenuation signal uses, for example, sound signal attenuation algorithms known to those skilled in the art. These algorithms take into account the enclosed environment of the passenger compartment whose acoustics, spatial constraints and sound reflections are known and modeled in the acoustic model of the passenger compartment.

In general, the attenuation sound signal has an amplitude similar to the amplitude of the initial sound signal and a phase in opposition to that of the initial sound signal, instead of listening to the overall sound signal, ie ie at the head of the passengers from the rest of the cockpit, out of the private acoustic zone.

Thus, the phases of the initial sound signal and the attenuation sound signal being in opposition, the overall sound signal resulting from the superposition of these two sound signals, that is to say resulting from the sum of these two signals, presents an amplitude lower than the amplitude of the initial sound signal, ie an attenuated amplitude, see canceled.

More precisely, the attenuation sound signal is equal to the initial sound signal as received by the reception element for which the amplitude of this initial sound signal is maximum, except that its phase is in opposition to that of this signal. sound signal and that it has a phase delay equal to the distance between the receiving element for which the amplitude of this initial sound signal is maximum and the head of the passenger for which the initial sound signal is attenuated, divided by the speed of sound in the air. In practice, this phase delay is equal to the distance between the receiving element for which the amplitude of this initial sound signal is maximum and the headrest of said passenger, or a control receiving element disposed in this support. -head.

Alternatively, different phase delays may be taken into account and the attenuation of the initial sound signal may be maximum in other places of the private acoustic zone. For example, the phase delay may be equal to the distance between the receiving element for which the amplitude of this sound signal initial is maximum and the place where the propagation of the initial sound signal and / or its echoes can be optimally attenuated in the vicinity of the boundaries of the passenger's private acoustic space for which the sound signal is attenuated, divided by the speed of the its in the air.

For example, an initial sound signal from, for example, the driver will be attenuated or canceled, not at a single point corresponding to the center of the front passenger's head, but at the entrance of the front passenger's private acoustic space. -Left, to the right of the armrest for example.

In general, even if the loudspeakers are optimized to minimize the initial sound signal in the immediate vicinity of a passenger's head, the sound signal will preferably be attenuated where it can best be. Depending on its direction of propagation and the orientation of the speakers in the vehicle, a particular initial beep may be attenuated from the armrest, and other sound signals will be attenuated a little closer to the passenger.

The location of the private acoustic zone where the attenuation of the initial sound signal is optimized depends on the propagation of this initial sound signal and the limits imposed by a small number of loudspeakers.

If the place of emission of the initial sound signal is not situated in the predetermined part of the private acoustic zone for which the initial sound signal is to be attenuated outside the private acoustic zone, no attenuation sound signal 'is determined and issued on the basis of this initial tone.

The control unit is also preferably programmed to determine the main propagation direction of the initial sound signal.

This is possible from the determination of the place of emission and the acoustic model of the cabin.

For the sake of simplification, it is considered here that the initial sound signal was simple. In practice, at a given location in the private acoustic zone, there are several initial sound signals (music, voices, noises, etc.) coming from different sound sources.

The control unit then controls the emission of the attenuation sound signal by one or more sound emission elements distributed in the passenger compartment and adapted to emit in the zone of the passenger compartment located outside the private acoustic zone.

The attenuation sound signal is preferably emitted by the elements sound emission device for emitting the attenuation sound signal in a transmission direction close to the direction of propagation of the initial sound signal, in the opposite direction to the propagation of the initial sound signal.

The control unit is therefore programmed to select the appropriate sound emission element or elements.

For example, to attenuate an initial sound signal propagating in a longitudinal direction from front to rear, the attenuation sound signal is emitted by a transmitting element emitting at least one longitudinal component, from the rear to forward.

The determined attenuation sound signal also takes into account the position of the sound emission element implemented in step c).

In the case where several transmission elements are used, the determined attenuation sound signal may therefore be different for each sound emission element.

The initial sound signal, corresponding here for example to the voice of the passengers sitting in the private acoustic zone, is thus attenuated or even canceled in at least part of the rest of the passenger compartment, for example at least near the position of the head at least one passenger while seated in the area of the passenger compartment outside the said private acoustic zone.

The position and number of sound emission elements are optimized to provide the best possible attenuation.

It is advantageous to have a reception element and a sound emission element in the headrest of the private acoustic zone since the attenuation algorithm can thus obtain information on the optimal delay to be applied for the signal. sound attenuation to be determined.

In particular, it should be mentioned that the phase-opposition attenuation signal calculated to be emitted by each sound emission element, for example each loudspeaker, takes into account the sum of the initial sound signals to be attenuated by this signal. attenuation, taking into account for example an estimate of the propagation and reflections of the initial sound signals emitted by each initial sound source. Each loudspeaker will thus emit a global attenuation signal comprising, for example, a first attenuation signal with a strong amplitude in phase opposition with a first initial signal emitted by a first close enough initial source added to a second attenuation signal with a low amplitude in phase opposition with a second initial sound signal emitted by a second initial source compensating for the nth reflection (rather attenuated) of this second sound signal.

In another place, another speaker will emit a mixture of these first and second attenuation signals, but with different phases and amplitudes. Some initial sound signals will not be attenuated by this other speaker as not attenuable by this speaker (for example because of its position relative to the source of these initial sound signals) or not present there.

Each passenger may at any time decide to deactivate the surrounding private acoustic zone by means similar to those described for activation.

The device according to the invention makes it possible to attenuate the initial sound signal and its reflections thanks to the reception of all the sound signals by the different reception elements.

In addition, preferably, the method according to the invention comprises an additional step of controlling the effectiveness of attenuation of the initial sound signal. The reception elements arranged outside the private acoustic zone receive the overall sound signal corresponding to the superimposition of the initial sound signal and the attenuation sound signal. It is preferably provided that they transmit to the control unit information on this overall sound signal, which makes it possible to check the effectiveness of the attenuation by comparing the amplitude of the overall signal and the amplitude of the sound signal. initial. The reception elements are thus used to establish a control loop to best adapt the attenuation algorithm.

For this purpose, the control unit preferably uses the control reception elements located at the headrests of the seats not included in the private acoustic zone.

As mentioned above, the attenuation sound signal is determined, for example, by taking into account only or essentially the initial sound signal received by the reception element that best captures this signal, that is to say by taking into account the initial sound signal received by the receiving element for which the initial sound signal has the greatest amplitude. As a variant, the determination of the attenuation sound signal takes into account a weighted average of the initial sound signal received by different reception elements.

The acoustic reflections of this initial sound signal on the walls of the passenger compartment and its repetitions in the passenger compartment are taken into account by the emission of a plurality of attenuation signals, taking into account the propagation delays of the reflections and the acoustic model of the cabin, using an echo cancellation algorithm running on a sliding time window. Thus, the control unit is programmed to recognize patterns of sounds repeated over time with a decreasing amplitude, and attenuate or cancel them with a suitable decreasing coefficient.

A maximum time window is defined to search for these reflections, the duration and the attenuation coefficient of which are defined from the intrinsic characteristics of the vehicle (micro-wall distance, reflection coefficient of the wall, etc.).

The phase shift and the difference in amplitude of the initial sound signal with its reflections and / or repetition makes it possible to correlate the reality of the acoustic reflections and absorptions with what was expected in the acoustic model of the passenger compartment established for example on the basis of a statistical occupancy model with four passengers. The acoustic model of the cabin can be adjusted in real time to take into account these differences, thus allowing to take into account the occupancy of the passenger compartment and the various obstacles present (people of different sizes, parcels, hanging clothes. ..).

In addition, in order to promote private discussion between two passengers of the same private acoustic zone, said control unit can also be programmed to determine, according to the initial sound signal and its place of emission, a sound signal of amplification or amplification sound signals, so that each amplification sound signal is in phase with the initial sound signal, i.e. has the same phase, in each part of the private acoustic zone where a passenger listens to this initial sound signal and to control the transmission of this amplification sound signal. This selectively amplifies the sound of a passenger's voice for another passenger, or several other passengers.

In addition, the initial sound signals emitted by certain sound sources such as the multimedia system or the vehicle telephone may be, according to the configuration of the passengers, broadcast only in certain private acoustic zones, so that the sound signals emitted by these sound sources can be heard only by the passengers located in the private acoustic zones in which these sound signals are broadcast.

The device and the method according to the invention also allow the selective attenuation of the other components of a sound signal, namely in particular the music and the engine noise, as described in the example below.

We will describe in the following an example of implementation of the invention in the passenger compartment of the single figure. The device according to the invention makes it possible to arrange a maximum of four private acoustic zones surrounding each seat 103, 104, 105, 106.

In this example, the device is programmed to selectively attenuate certain components of the sound signal received in each private acoustic zone.

The passenger seated on the driver's seat 103 on the front left wants to listen to music without being disturbed by the ambient noise or conversations.

Passengers seated in the right-front seat 104 and the left-back seat 105 behind the driver wish to chat together without being heard by other passengers and without being disturbed by other passengers.

The passenger sitting on the right rear seat 106 wants to sleep, and therefore hear as little noise as possible.

Each passenger indicates his wishes to the control unit through the control interface. The device according to the invention is then configured to arrange three private acoustic zones detailed below. The music is generated by a centralized audio player.

The side speakers HP3, HP4 disposed in the headrest 103A of the seat 103 front left broadcasts the music for the passenger of this seat.

In the private acoustic zone surrounding the passenger sitting in the right front seat 104 and the one sitting in the left rear seat 105: for the right front seat passenger 104, the control unit determines a first sound attenuation signal and controls its emission by the speaker before HP2 arranged in front of this passenger.

The first sound attenuation signal is in phase opposition with the sum of the following signals, which propagate from the back to the front:

sound signal received by the part of the microphone M1 facing towards the rear and corresponding to the voice of the passenger seated on the left front seat 103,

sound signal received by the microphone M7 and corresponding to the voice of the passenger seated on the right rear seat 105,

sound signal emitted by the side speakers HP3 and HP4 of the seat 103 front left and corresponding to the music listened to by the passenger sitting on this seat,

- sound signal received by the part of the microphone M2 directed towards the back and corresponding to the ambient noise.

These sound signals are attenuated in phase opposition, with a delay equal to the distance between the microphone having received the signal with the greatest amplitude and the microphone disposed in the headrest 104A of the right front seat 104, divided by the speed sound in the air.

The residual signals received by the microphone M5 of the headrest 104A of the right front seat 104 after this attenuation are also taken into account. Then add to the first attenuation signal described above a counter-reaction signal in phase opposition to the sum of the following signals:

- residual sound signal of the ambient noise detected by the front parts of the microphones M2 and M3 which is reflected on the front wall of the passenger compartment, in particular the windshield, and which is received by the microphone M5 at the instant [t + n] with a weakened amplitude, using a sliding time-slot echo cancellation algorithm,

- any residual sound signal received by a microphone close to the corresponding passenger.

Of course, the voice of the front seat passenger 104 right is received by the microphone M3 and preserved to allow the conversation with the passenger sitting on the seat 105 rear left.

In addition, preferably, the sound signals received by the receiving elements and corresponding to the voice of the passenger seated on the rear seat 105 left are amplified by their emission by the side speakers HP5 and HP6 arranged in the headrest 104A of the seat 104 front right.

The side speakers HP5, HP6 then emit an amplification sound signal equal to the sum of the sound signal received by the microphone M6, corresponding to the voice of the left rear passenger, and a comfort sidetone.

For greater comfort and realism, the HP5 side speaker located to the right of the headrest 104A can emit the sound signal received by the M6 microphone slightly louder than the HP6 side speaker to the left of the headrest 104A, in order to spatialize the sound. The sidetone corresponds to a return sound signal from the voice of the passenger seat 104 right front, it is therefore the sound signal received by the microphone M3 weakened. It is emitted by the two side speakers HP5, HP6 with the same amplitude.

In addition, one or the other or both side speakers HP5, HP6 can participate in the sound attenuation by emitting a second attenuation signal in phase opposition to the sound signal corresponding to the ambient noise received by the parties. M3 and M2 microphones facing forward. These loudspeakers make it possible to attenuate the components of the initial sound signal propagating from front to rear.

The attenuation coefficients and delays applied for the attenuation of the selected sound signals are reevaluated in real time to eliminate the residual sound signals received by the microphone M5 disposed in the headrest 104A of the right front seat. In general, each microphone identifying sound signals close to the passenger is taken into account to refine the feedback signal.

For the passenger seated in the left rear seat: the control unit determines a third attenuation signal emitted by the rear speaker HP7 disposed opposite the left rear seat, which is in phase opposition of the sum of the sound signals correspond to the ambient noise coming from the rear and reflections on the rear wall of the vehicle, namely

the sound signal received by the part of the microphone M8 facing towards the rear, and

- sound signal received by the M10 microphone part facing backwards.

For the attenuation of these noises, a joint contribution from the speakers HP7, HP8 placed on the front seats towards the rear of the passenger compartment can be used.

The voice of the passenger seated on the seat 105 on the left, received by the microphone M6, is preserved.

The control unit also controls transmission by the side speakers HP9 and HP10 disposed in the headrest 105A of the seat 105 of a fourth attenuation signal.

Here, the fourth attenuation signal determined by the control unit comprises an anti-phase signal of the sum of the following signals:

sound signal received by the microphone M7 and corresponding to the voice of the passenger seated on the seat 105 on the right,

- sound signal emitted by the side speakers of the left front seat HP3 and HP4 and corresponding to the music listened to by the passenger sitting in the front left seat,

the sound signal received by the part of the microphone M8 facing forward, and

- sound signal received by the M10 part of the microphone facing forward.

These sound signals are attenuated in phase opposition, with a delay equal to the distance between the microphone having received the signal with the greatest amplitude and the microphone disposed in the headrest 105A of the rear left seat 105, divided by the speed sound in the air.

Residual signals received by the microphone M9 of the headrest 105A after this attenuation are also taken into account.

The microphone M9 disposed in the headrest of the seat 105 rear left is indeed used to detect the residual ambient noise, to assess whether the ambient noise is properly attenuated. Depending on the place of emission of the audible signal to be attenuated, the fourth attenuation signal is emitted by one or other of the side speakers HP9, HP 10, or both.

Then add to the fourth attenuation signal described above a counter-reaction signal in phase opposition to the sum of the signals following:

- residual sound signal of the ambient noise which is reflected on the front and / or rear walls of the passenger compartment, in particular the windscreen, and which is received by the microphone M9 at the instant [t + n] with a weakened amplitude , using an echo cancellation algorithm,

The side speakers HP9, HP10 also emit an amplification sound signal equal to the sum of the sound signal received by the microphone M6 and corresponding to the voice of the left rear passenger and a comfort sidetone.

For the driver who listens to music:

The control unit determines a fifth attenuation signal that is output from the front speaker HP1, which is in phase opposition with the sum of the following signals:

sound signal received by the part of the microphone M3 facing backwards and corresponding to the voice of the passenger seated on the seat 104 before right,

sound signal received by the microphone M6 and corresponding to the voice of the passenger seated on the seat 105 rear left,

sound signal received by the microphone M7 and corresponding to the voice of the passenger seated on the right rear seat 106,

For the determination of the attenuation signal, a delay is applied to each sound signal taken into account. This delay is equal to the distance between each microphone and the microphone M4 disposed in the headrest 104 of the left front seat, divided by the speed of sound. An additional phase and amplitude correction can be applied, taking into account the acoustics of the passenger compartment and in particular the obstacles between the microphone receiving the sound signal or the speaker emitting the attenuation signal and the passenger.

As previously, the residual sound signals received by the microphone M4 located in the headrest of the left front seat, namely in particular the residual sound signal of the ambient noise reflected by the front wall of the passenger compartment, and which is received by the M4 microphone at the instant [t + n] with a higher amplitude low than that of ambient noise are also taken into account in the determination of the attenuation signal.

The control unit also controls transmission by the side speakers HP3 and HP4 disposed in the headrest of the left front seat of a sixth attenuation signal in addition to the music broadcast. This sixth attenuation signal attenuates the ambient noise as well as the residual sound signals.

The HP3 and HP4 side speakers compensate for residual sound signals that are not completely longitudinal. In the case of a car, these compensations are essentially limited to reflections of noise on the walls of the vehicle.

For the passenger in the back seat on the right, who sleeps:

The rear speaker HP8 disposed opposite this passage emits a seventh phased attenuation signal of the sum of the following signals:

- sound signal received by the M6 microphone corresponding to the passenger's voice from the seat on the left,

- sound signal received by the rearward-facing part of the M12 microphone corresponding to the ambient noise,

- sound signal received by the rearward-facing part of the M10 microphone corresponding to ambient noise and sound reflections on the rear wall of the passenger compartment. For the attenuation of these noises, a joint contribution of the side speakers HP7 and HP8, arranged opposite the seats of the seat, will be used.

The control unit also determines a ninth attenuation signal emitted by the side speakers HP11 and HP12 located in the headrest 105B of the right rear seat of the seat 105.

It is a signal in phase opposition of the sum of the following signals:

sound signal received by the microphones M1, M3 corresponding to the voice of the other passengers,

- sound signal corresponding to the music played by the HP3 and HP4 side speakers located in the headrest of the front left seat,

- sound signal received by the M10 and M12 microphones (front part) corresponding to the ambient noise, each with a delay equal to the distance between the microphone receiving this signal with the largest amplitude and the microphone M11 located in the headrest 106A of the right rear seat 106 divided by the speed of sound in the air.

To this is added a tenth attenuation signal determined in phase opposition with the residual ambient noise reflected by the front and rear walls, received at times t + n shifted with a weakened amplitude, using an algorithm of echo cancellation.

In another example, two private acoustic zones are provided: a front zone including the two front seats and a rear zone comprising the rear seat. In the case of a taxi, the two zones can be considered as "private acoustic zone", the front zone to ensure the confidentiality of the driver and the rear zone to ensure the confidentiality of the passengers.

Similarly, in the context of family use, the front area (the driver and his front passenger) would be considered as a "private acoustic zone" vis-à-vis the rear passengers. In this example, the radio or media player is turned on.

When the driver wishes to have a private conversation with the front passenger, he configures the front zone as a "private acoustic zone", either by using a button or by using the "private" keyword if the car is equipped with a control system. speech Recognition.

The microphones of the entertainment system then receive the sound signals emitted in the car. These signals include the sounds emitted inside the car, the sound of the radio emitted by the entertainment system and the conversations between the passengers.

The device and the method according to the invention make it possible to create private acoustic zones, especially for conversations between two or three passengers.

They also make it possible to broadcast music or audio content (for example a telephone conversation) selectively to each of the passengers, that the others will not hear and to attenuate the ambient noise, and in particular the noises of the engine.

In the event of an emergency (emergency braking, shock, airbag triggering, alarm call from a user), the device can be automatically deactivated For safety reasons.

One can consider the use of headrest incorporating directional speakers near the ears of passengers, arranged in wings of the headrest folded on both sides of the passenger's head.

Finally, in order to achieve a better attenuation of the desired sound signals, the attenuation signal intended to attenuate a given initial sound signal can be emitted using at least two loudspeakers. A beamforming technique is preferably used to better center the cancellation of the sound at the level of the passengers' heads. This technique is known to those skilled in the art and will not be described in more detail here. In order to determine the beamforming target, here for example the passenger's head, a camera could be used to track down the passenger's face and thus determine the position of the passenger's head in the private acoustic zone.

For the front passengers of the vehicle, it is then expected for example a camera arranged in the middle of the windshield, for example on the central rearview mirror, and two speakers arranged in front of each front seat, a total of four front speakers oriented towards the rear of the vehicle and distributed along the dashboard of the vehicle.

Each private acoustic zone therefore corresponds to a specific acoustic zone delimited. Each zone is configured, by and according to the wishes of his or her passengers, so as to select the sound signals to be valued. These signals are amplified according to the need in the area and attenuated outside the area. It is thus possible to define a private acoustic zone comprising only the front seats, occupied for example by two parents, which allows to sleep a baby serenely in the back while hearing it if he wakes up. It is also possible to define a rear private acoustic zone in case one would have a dog for example in the back seat in order to be able to drive more comfortably without hearing any barking because these barking would be assimilated to a passenger voice since they would be emitted at a height in the vehicle being close to the height of a human or child's mouth, that is to say, emitted in front of the microphone located in front of the rear seat (microphone located behind a front seat ).

Claims

1. Device for the arrangement of at least one private acoustic zone in the passenger compartment of a vehicle, comprising:

a plurality of reception elements (M1, M2, M3, M4, M5, M6, M7, M8, M9, M10, M11, M12) of at least one initial sound signal, distributed in the passenger compartment of the vehicle,

at least one sound emission element (HP1, HP2, HP3, HP3, HP4, HP5, HP6, HP7, HP8, HP9, HP10, HP10, HP11, HP12) adapted to emit an attenuation sound signal in a zone from the outer cockpit to the first private acoustic zone and an amplification sound signal, and

- a control unit programmed for

a) receiving and processing information relating to each initial sound signal transmitted by said receiving elements (M1, M2, M3, M4, M5, M6, M7, M8, M9, M10, M11, M12) to separate the different components; the initial sound signal received and to identify a place of emission of each of the components of this initial sound signal, said components of the initial sound signal comprising the sound of the voice of at least one passenger,

(b) determine, based on each initial sound signal and its place of emission,

a sound signal for amplifying the sound of the voice of said passenger so that this amplification sound signal is in phase with the initial sound signal in a part of the private acoustic zone,

said attenuation sound signal so that, in at least part of the zone of the passenger compartment outside the private acoustic zone, the amplitude of the overall sound signal resulting from the superposition of each initial sound signal and the sound signal attenuation is less than the amplitude of the initial sound signal and

c) controlling the emission of this amplification sound signal and of this attenuation sound signal by the at least one sound emission element (HP1, HP2, HP3, HP3, HP4, HP5, HP6, HP7, HP8, HP9, HP10, HP10, HP11, HP12).

2. Device according to claim 1, wherein in step a), the control unit is also programmed to determine a direction of propagation of each initial sound signal.

3. Device according to one of claims 1 and 2, wherein said control unit is programmed to compare, in step a), the information relating to each initial sound signal transmitted by each receiving element of said plurality of receiving elements (M1, M2, M3, M4, M5, M6, M7, M8, M9, M10, M11, M12) to deduce the place of emission of this initial sound signal.

4. Device according to one of claims 1 to 3, wherein said information relating to each initial sound signal comprise at least its phase and / or its time delay and / or its amplitude.

5. Device according to one of claims 1 to 4, wherein, said control unit is programmed to determine, in step b), the attenuation sound signal so that the phase of this sound signal d attenuation either in phase opposition with respect to the sum of each initial sound signal in said part of the zone of the passenger compartment outside the private acoustic zone.

6. Device according to claim 2, wherein there is provided a plurality of sound emission elements, and wherein the control unit is programmed for, in step c), to control the transmission of the audible signal. attenuation by a part of the plurality of sound emission elements determined according to the propagation direction of each initial sound signal.

7. Device according to one of claims 1 to 6, wherein the control unit is programmed for, in step c), controlling the emission of the attenuation sound signal intended to attenuate the same initial sound signal by at least two sound emission elements.

8. Device according to one of the preceding claims, for the arrangement of a plurality of private acoustic zones in the passenger compartment of the vehicle, comprising said private acoustic zone and at least one additional private acoustic zone, in which it is provided in minus one additional sound emission element (HP1, HP2, HP3, HP3, HP4, HP5, HP6, HP7, HP8, HP9, HP10, HP10, HP11, HP12) of an additional attenuation sound signal in an area of the outside cabin to the additional private acoustic zone, and wherein said control unit is programmed to, in step b), determine, according to each initial sound signal and its transmission site, said additional attenuation sound signal so that, in the zone of the passenger compartment outside the additional private acoustic zone, the amplitude of the overall sound signal resulting from the superposition of each initial sound signal and the signal additional attenuation sound is less than the amplitude of said initial sound signal and, in step c), controlling the emission of this additional attenuation sound signal by said sound emission element (HP1, HP2, HP3, HP3, HP4, HP5, HP6, HP7, HP8, HP9, HP10, HP10, HP11, HP12) additional.

9. Method of arranging at least one private acoustic zone in the passenger compartment of a vehicle comprising the following steps:

receiving at least one initial sound signal by a plurality of reception elements (M1, M2, M3, M4, M5, M6, M7, M8, M9, M10, M11, M12),

processing information relating to each initial sound signal transmitted by said reception elements (M1, M2, M3, M4, M5, M6, M7, M8, M9, M10, M11, M12), to separate the different components of the sound signal initial received and determine a place of emission of each of the components of this initial sound signal, said components of the initial sound signal comprising the sound of the voice of at least one passenger,

determination, according to each initial sound signal and its place of emission, of a sound amplification signal of the voice of said passenger so that this amplification sound signal is in phase with the signal initial sound in a part of the private acoustic zone, and an attenuation sound signal such that, in at least a part of the zone of the passenger compartment outside the private acoustic zone, the amplitude of the overall sound signal resulting the superposition of each initial sound signal and the attenuation sound signal is less than the amplitude of the initial sound signal and

- emission of this amplification sound signal and attenuation sound signal.

10. Motor vehicle comprising at least one device according to one of the preceding claims, providing at least one private acoustic zone in the passenger compartment of the vehicle.