WO2007101462A1

WO2007101462A1 - Loudspeaker arrangement in a motor vehicle, and a method for driving the at least one loudspeaker

Info

Publication number: WO2007101462A1
Application number: PCT/EP2006/011346
Authority: WO
Inventors: Holger Opfer; Gordon Seitz; Thomas Jänsch
Original assignee: Volkswagen Aktiengesellschaft
Priority date: 2006-03-01
Filing date: 2006-11-27
Publication date: 2007-09-13
Also published as: DE102006045385B4; WO2007098916A1; DE102006045385A1

Abstract

The invention relates to a loudspeaker arrangement in a motor vehicle, comprising at least one loudspeaker, where the loudspeaker can be driven by at least one driver assistance system (4, 5) in order to produce audible warning signals containing direction information, the loudspeaker being in the form of a surface loudspeaker (1), particularly an electrostatic one, which is arranged in the roof lining or forms the roof lining, and to an associated method.

Description

description

Speaker arrangement in a motor vehicle and a method for controlling the at least one speaker

The invention relates to a loudspeaker arrangement in a motor vehicle and a method for controlling the at least one loudspeaker, by means of which an acoustic warning with direction information for the motor vehicle driver is possible.

From DE 196 52 930 A1 a distance warning system with an acoustic warning device is known, which emits warning signals as soon as an obstacle in a predetermined distance range to the warning system is measured, the warning device with at least two depending on the location of the obstacle separately controllable acoustic transmitters, Preferably loudspeakers, is provided, which are simultaneously controllable via separate channels such that the location and / or movement of the sound heard by the operator of the vehicle gives an indication of the direction in which the measured obstacle is located.

Similar devices are known from DE 103 06 885 A1, DE 103 45 680 A1 and DE 210 21 958 U1.

From WO 99/56498 an acoustic element is known, which comprises any number, preferably two, layers and at least one plastic film spaced from the layer, wherein at least one layer comprises at least one porous layer and the porous layer and the plastic film substantially only come in contact with each other at certain support points, while at the other locations an air gap between the porous layer and the plastic film is present. The porous layer is either electrically conductive or at least coated on one of its surfaces so that it is electrically conductive. The plastic film is charged or provided with an electrically conductive surface. The support points at which the plastic film and the porous layer come into contact with each other are arranged so that the entire structure can change its thickness. By applying a signal to at least one porous layer, the plastic film is then caused to vibrate, wherein preferably also the other porous layer is subjected to the antiphase signal. This arrangement represents an electrostatic flat speaker. Electrostatic Area loudspeakers have the property of a particularly pronounced directional characteristic, ie a pronounced sound radiation perpendicular to the loudspeaker level. Since they are usually made of plastic, they are characterized in addition to their flat design further by good formability and low weight.

Based on the known prior art, the invention is based on the technical problem of providing a loudspeaker arrangement for acoustic warning with directional information which can be arranged in a motor vehicle in a space-saving manner and to provide an associated method.

The solution of the technical problem results from the objects with the features of claims 1 and 9. Further advantageous embodiments of the invention will become apparent from the dependent claims.

For this purpose, the speaker is designed as, in particular electrostatic, area loudspeaker, which is arranged in the headliner or forms the headliner. As a result, the headliner can be utilized in a very space-saving manner and, if necessary, dispensed with a distributed arrangement of loudspeakers in the motor vehicle. The direction information can now be generated depending on the embodiment. It should be made clear that the control by the driver assistance systems need not be directly directly, but can also be done indirectly via other control devices.

In a preferred embodiment, the electrostatic surface loudspeaker is arranged above the vehicle seat, wherein the area loudspeaker is segmented and the area loudspeaker segments can be controlled independently of one another.

Further preferably, the area speaker segments are arranged in different directions to the vehicle seat, wherein the at least one direction-determining area speaker segment is driven exclusively or with a larger amplitude than the remaining area speaker segments. Clearly, this can be understood that above the head of the driver, a Flächenlautsprecherpanel is arranged with four square segments, the head is centered to the panel. Then the segments with their centroids are left in front of the head, right in front of the head, left behind the head and right behind the head. If now a direction information "left behind" to be transmitted, the segment, which is located on the left behind the head, as a direction-determining segment exclusively or with a larger amplitude with the warning signal applied. In a further preferred embodiment, the remaining

Area speaker segments with the same or similar signals as the selected, direction-determining Flächenlautsprechersegment driven, just with a smaller amplitude. This is based on the following finding: Since the effective area is smaller in radiation only through the direction-determining area speaker segment in relation to the total area of the loudspeaker, it also radiates less directionally in relation to the overall loudspeaker. This leads to the other vehicle occupants perceive the warning signal stronger. By controlling the other segments with the same or very similar signal of lower amplitude, the deviation is reduced by synchronously oscillating surface pole and improves the directional radiation characteristic, so that, as a result, the passengers are less disturbed.

Alternatively or additionally, there is another way of affecting the passenger in the direction-determining segment repeatedly pulse-like and / or slightly longer with the warning signal and thus allow the driver's hearing a location and bring it through the repetition again and again on this direction perception , Clearly, therefore, the direction-determining segment with a higher amplitude is only temporarily activated by adding up the pulse to a uniform basic signal for all segments. This is done according to the well-known "principle of the first wavefront", wherein the first wavefronts of a sound in the spatial perception of the hearing are crucial and initially obtained even with a wavefront change of the directional impression obtained.

In addition, it should be noted that the embodiments made here for the driver's vehicle seat can of course also be applied to any vehicle seat.

In a further preferred embodiment, at least two independently controllable loudspeakers are arranged in the headliner, it being possible in each case to generate a signal for the loudspeakers by means of a binaural head-related transfer function (HRTF) in a control unit in dependence on the desired directional information. This embodiment makes use of the knowledge about the spatial perception of binaural signals in a control unit in order to pre-process the signals to be radiated by linear signal filtering in such a way that the target person, in spite of the radiation from above, thinks the sounds come from another direction. The spatial perception of sounds is determined by sound reflections and diffraction at the head and the outer ear, which generally leads to a different coloring of the sounds on the left and right ear. Here, level and transit time differences play a decisive role. This means that sounds that are radiated from the back right, are perceived differently to those that occur, for example, from the right front. This different perception behavior is summarized in the binaural outer ear transfer function, ie that both amplitude and phase over the frequency as well as the time course of the coloring to both ears is different. With knowledge of the angle-dependent and height-dependent HRFT and corresponding signal preprocessing, the binaural signal can be "colored" in such a way that it sounds to the target person as if it came from the right behind and not from the top, for example Accordingly, the left ear transfer function on the left ear associated speaker and the right ear transfer function on the right ear associated speaker are set accordingly.

Of course, the embodiments with direction-determining surface speaker segment and HRFT can be combined with each other.

In an alternative embodiment, the headliner is formed from panel material of the area loudspeakers, wherein at least individual segments can be controlled differently and generate an acoustically directed warning signal by means of a beamforming. In this case, the panel material is preferably provided with a stiffening, which contains the back volumes necessary for the loudspeakers or the optionally arranged absorber. Furthermore, this allows a configuration of individual sky segments as speakers, other than microphones, for example, for hands-free equipment and / or DVE (digital voice enhancement). These have, depending on their area and the operating mode (mono) a pronounced directional characteristic, which can be further increased by the above-mentioned beamforming. Furthermore, parts of the panel (for example, the electrically conductive layers) can be defined and configured as electrical leads, so that only one plug must be mounted and no expensive copper cables must be laid. If required, an additional electrical shielding can then be integrated into the panel. The panel speakers can be used in addition to the individual support of the sound system and as a tweeter replacement. In this case, for example, the high-frequency components are radiated in normal sound mode in addition by the flat speakers in the headliner in stereo mode and supported by woofer or subwoofer accordingly. Passive sound absorption can be achieved through porous cover materials of the panel at high frequencies.

The highest possible sound absorption is desirable to prevent unwanted reflections from the headliner, thereby minimizing the background noise in the vehicle.

- A - To improve the absorption behavior at low frequencies, an absorber material can be arranged behind the panel, with further preference being given to adapting the cavity resonance of the damped rear volume. In addition to the size of the back volume, further parameters for influencing the absorption behavior are the panel stiffness, the size of vents for the back volume, the perforation of a leather or fabric stretched over the panel, the structure of the porous absorber (air resistance, porosity, layer structure, thickness of the layers). or optionally additional openings of the panel. The overall construction is a combination of different types of absorber. For example, the perforated fabric or leather stretched over the panel acts as a hole absorber, the panel itself as a panel absorber, the membrane of the panel as a film absorber, the rear volume as a Helmholtz absorber and a composite of several layers Absorber as a layer absorber. By suitable choice of the parameters, an overall absorber optimized over the frequency band can then be created. Further enhancement of low frequency absorption is possible through Semi-Active Noise Control or Active Noise Control. With the Semi-Active Noise Control, the passive absorber is detuned, ie the resonances are adjusted by controlling the membrane. Clearly, the impedance is adjusted by controlling the diaphragm, which registers the background noise when hitting the headliner. In Active Noise Control, on the other hand, the noise field is calculated from the measurement of sound pressure and sound velocity and actively canceled by destructive interference, in which case both a controller and a controller can be used. Here, the relatively high spatial sampling of the sound field by the integrated microphones of great advantage. In particular, in Active Noise Control, the panel is preferably designed as a multilayer panel, wherein at least two layers are designed as a microphone. As an alternative to the separately defined microphone panels, the speaker panels can also be used simultaneously as microphones of reduced sensitivity. It goes without saying that the semi or active noise control can be combined with the passive sound absorption measures. A control unit adapts both the adaptation of the sky to the current requirements of communication as well as the functions DVE, handsfree, private calling, rear seat entertainment, individual driver HMI (parking assistance, traffic, navigation announcements, warning sounds, beeps and info messages) as The adaptation to the acoustic comfort or image needs by Active Noise Control or sound design.

In an embodiment with directional loudspeakers and directional microphones, in addition, improved communication in the motor vehicle between the occupants can be achieved, in particular hearing impaired persons can be better involved. For this purpose, it is first determined whether a vehicle occupant speaks louder than a threshold. The threshold for the volume can either be fixed or adaptive depending on the Volume of background noise and / or other occupants are selected. If a potentially hearing-impaired person is identified, his hearing ability is then determined as a function of the frequency. In this case, for example, proceed as follows. The occupant is fed his own voice in near real time with minimal delay (<10 - 25 ms) via a directional speaker. This has the consequence that this feels too loud and speaks quietly. By successively amplifying individual frequency components and evaluating the reaction of the occupant, the sensitivity to hearing can then be recorded. If the occupant does not change his volume, this is to be understood as an indication of the insensitivity in this frequency. If then the sensitivity over the frequency is known, it is subsequently possible for the occupant, via a suitable transfer function, to supply a signal adapted to the frequency response of his hearing to his speech. Since the hearing impaired hears this adjusted signal well, this will adjust its volume accordingly, which is more pleasant for the other occupants. It should be noted that this method is in principle independent of the specific installation location of the directional loudspeakers or directional microphones. Furthermore, a certain frequency response can be stored and assigned to a person, so that the frequency response does not have to be determined each time.

The invention will be explained in more detail with reference to a preferred embodiment. The single figure shows schematically a loudspeaker arrangement for emitting a direction information.

The loudspeaker arrangement comprises an electrostatic area loudspeaker 1, which is subdivided into four independently controllable area loudspeaker segments FS1-FS4 and are arranged in a square manner relative to one another. The electrostatic surface speaker 1 is arranged in the headliner of a motor vehicle above the vehicle seat of the motor vehicle driver. The electrostatic surface speaker 1 is arranged centrally above the head of the motor vehicle driver. Thus, for example, the area speaker segment FS 1 lies in a direction left front to the head of the motor vehicle driver. The area speaker 1 is associated with a control unit, which is designed for example as an audio signal processor 2 and can control the individual Flächenlautsprechersegmente FS1-FS4. The audio signal processor 2 is connected via a bus system 3 with a plurality of driver assistance systems 4, 5, which are designed, for example, as a parking assistance, lane-departure warning system. If a driver assistance system now detects a situation where the driver of the motor vehicle is to be warned acoustically, the driver assistance system generates a signal and transmits this to the audio signal processor 2. The signal includes, on the one hand, the information that should be warned and a direction information. The audio signal processor 2 now evaluates the signal and detects, for example, that the warning sound from should come left behind. Accordingly, the area speaker segment FS3 is driven exclusively or with a larger amplitude in comparison to the remaining area speaker segments FS1, FS2 and FS4. It should be noted that the connection between the driver assistance systems 4, 5 and the audio signal processor 2 can also be done directly while saving the bus system 3. It should also be noted that alternatively the flat-panel loudspeaker 1 may be circular in shape the area speaker segments are formed as circle segments. Depending on the subdivision then the direction information can be subdivided even finer. Since usually vehicle seats are designed to be displaceable, the head position of the motor vehicle driver is not static. Therefore, the area loudspeaker 1 should be dimensioned such that, irrespective of the vehicle seat positions and / or the seat position of the motor vehicle driver, it is ensured that in each case two area loudspeaker segments are located in front of and behind the head. For the embodiment according to FIG. 1, this means that if necessary the division of the area speaker segments is not 2x2 but 2x3 or 2x4.

Claims

claims

1) loudspeaker arrangement in a motor vehicle, comprising at least one loudspeaker, wherein the loudspeaker can be controlled by at least one driver assistance system to produce acoustic warning signals with direction information, characterized in that the loudspeaker is designed as, in particular electrostatic, area loudspeaker (1) which is arranged in the headliner or forms the roof lining.

2) loudspeaker arrangement according to claim 1, characterized in that the, in particular electrostatic, area loudspeaker (1) is arranged in the headliner over the driver's seat, wherein the area loudspeaker (1) is segmented and the Flächenlautsprechersegmente (FS1-FS4) are independently controllable.

3) loudspeaker arrangement according to claim 2, characterized in that the Flächenlautsprechersegmente (FS1-FS4) are arranged in different directions to the vehicle seat, wherein the at least one direction-determining Flächenlautsprechersegment is exclusively or with greater amplitude than the remaining Flächenlautsprechersegmente controllable.

4) loudspeaker arrangement according to claim 3, characterized in that the remaining Flächenlautsprechersegmente with the same signal as the selected direction-determining Flächenlautsprechersegment are controllable.

5) loudspeaker arrangement according to one of claims 2 to 4, characterized in that the direction-determining Flächenlautsprechersegment (FS1-FS4) is pulse-controlled and / or is controlled in time longer than the remaining Flächenlautsprechersegmente.

6) loudspeaker arrangement according to one of the preceding claims, characterized in that at least two mutually independently controllable speakers are arranged in the headliner, wherein by means of a binaural Direction information in each case a signal for the speakers can be generated.

7) loudspeaker arrangement according to claim 1, characterized in that the headliner of panel material of the area loudspeaker (1) is formed, wherein at least individual segments are controlled differently and by means of a beam shaping an acoustically directed signal can be generated.

8) loudspeaker arrangement according to one of the preceding claims, characterized in that the electrostatic surface loudspeakers (1) via an audio signal processor (2) are operated in addition as a semi or active noise control simultaneously.

9) A method for controlling a loudspeaker arrangement in a motor vehicle, by means of at least one designed as a surface speaker (1) speakers, in particular as electrostatic flat speaker trained speaker, which is controlled by at least one driver assistance system (4, 5), wherein the speaker arranged in the headliner is or forms the headliner, wherein the speaker generates an audible warning signal with a direction information.

10) A method according to claim 9, by means arranged in the headliner above the driver's seat area speaker (1), wherein the area speaker (1) is segmented and the Flächenlautsprechersegmente (FS1-FS4) are controlled independently of each other and are arranged in different directions to the vehicle seat, said the at least one direction-determining area speaker segment is driven exclusively or with a larger amplitude.

11) Method according to claim 10, characterized in that the area loudspeaker segments (FS1-FS4) are driven with the same signal.

12) Method according to one of claims 9 to 11, characterized in that the direction-determining surface speaker segment is repeatedly driven in a pulse-like manner and / or the signal is present for a longer time than at the remaining surface speaker segments. I JJ V Cl I dI Il Cl II IdOI l a uci πι ιoμι

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14) A method according to claim 9, characterized in that the headliner is formed of panel material of the area loudspeaker, wherein at least individual segments are controlled differently and by means of beamforming an acoustically directed signal is generated.