Device and method for reducing acoustic transmission from the interior of a vehicle

Abstract

In a first aspect of the invention, a device for reducing acoustic transmission of an audio output from a vehicle interior to an exterior area of ​​a vehicle is provided, comprising a control unit configured to automatically change the audio output depending on the vehicle speed, wherein the control unit is configured, when the vehicle speed is below a threshold value for the vehicle speed, to filter an audio signal for the audio output by means of a signal processor in order to change certain frequency ranges and / or to control a specific output unit of the vehicle.

Description

[0001] The present patent application describes a device and a method for reducing the acoustic transmission of an audio output, in particular a telephone conversation, from the interior of a vehicle to the exterior of a vehicle.

[0002] In modern vehicles, communication technology is an integral part of the driving experience. However, with audio output, especially phone calls, the transmission of sound waves—particularly in the low and mid-frequency ranges—from the speakers to the vehicle body presents a problem: when the vehicle is stationary or moving slowly, other road users can hear the audio. For example, at a traffic light, pedestrians or cyclists can overhear parts of a vehicle occupant's phone call because the audio output during the call is emitted through speakers mounted in the vehicle doors, and these sound waves are transmitted to body panels due to unfavorable acoustic coupling. This allows the sound waves to reach the exterior of the vehicle and be perceived by people there. Consequently, the privacy and data protection of the occupants are not guaranteed.

[0003] The current state of the art involves minimizing the problem through elaborate insulation or acoustic decoupling. However, these measures result in significant additional costs and / or weight. Furthermore, they impose limitations regarding speaker positioning and design in order to achieve perfect acoustic decoupling from the outside.

[0004] The aim is therefore to improve the current situation and ensure the privacy and data protection of the occupants by minimizing the transmission of sound waves, especially in the low and mid-frequency range, from the loudspeakers to the vehicle body.

[0005] To achieve this goal, the invention provides a device and a method according to the independent claims. Further developments of the invention are the subject of the dependent claims.

[0006] In a first aspect of the invention, a device for reducing acoustic transmission of an audio output from a vehicle interior to an exterior area of ​​a vehicle is provided, comprising a control unit configured to automatically change the audio output depending on the vehicle speed, wherein the control unit is configured to filter an audio signal for the audio output by means of a signal processor in order to change certain frequency ranges, and / or to control a specific output unit of the vehicle when the vehicle speed is below a threshold value for the vehicle speed.

[0007] Depending on the vehicle speed, the control unit can switch to the digitally filtered audio signal, especially if there is no speaker in the head area of ​​a seat in the vehicle.

[0008] Depending on the vehicle speed, the control unit can activate speakers located in the head area of ​​a seat as the output device. The control unit can switch the audio signal output to the speakers.

[0009] The audio signal can be a telephone signal and the audio output a telephone conversation.

[0010] The threshold for vehicle speed can be in a range of 0-30 km / h, in particular 0-50 km / h.

[0011] The signal processor can use a low-pass, high-pass, band-pass and / or notch filter to attenuate frequency ranges.

[0012] The change to the audio output can be activated and / or deactivated by the vehicle user.

[0013] The device can be part of the vehicle's infotainment system.

[0014] In another aspect, a method for reducing acoustic transmission of an audio output from a vehicle interior to an exterior area of ​​a vehicle is described, comprising the steps of: detecting the vehicle speed when the vehicle speed is below a vehicle speed threshold, changing the audio output depending on the detected vehicle speed, filtering the audio signal for audio output using a signal processor to modify certain frequency ranges, and / or controlling a specific output unit of the vehicle.

[0015] The invention is now also described with regard to the figures: Fig. Figure 1 describes a schematic representation of the device for reducing acoustic transmission, Fig. Figure 2 shows a schematic representation of the procedure for reducing acoustic transmission.

[0016] The basic idea of ​​the present invention is to equip modern vehicles with loudspeakers not only in the body but also in the seat or in the head area of ​​the seat. If the vehicle's speed falls below a predetermined and / or configurable threshold or moves within a predetermined and / or configurable speed range, the audio output is changed, preferably continuously, so that the output is essentially or exclusively via the loudspeakers in the head area of ​​one or more seats. The type of audio output for which this change is made can be configurable. For example, music output can remain unchanged, while telephone call output or navigation output is changed. It can also be provided that a vehicle user can manually direct the audio output exclusively to the loudspeakers in the head area of ​​the seat.

[0017] In vehicles without built-in speakers, the audio output can be digitally filtered to acoustically decouple it from the vehicle body and minimize sound transmission to the exterior. This may result in some loss of sound quality; however, speech intelligibility is paramount, especially during phone calls, making this loss acceptable. If the vehicle's speed falls below a predetermined and / or configurable threshold or remains within a predetermined and / or configurable speed range, the audio output is adjusted, preferably continuously, so that the sound is essentially filtered through the speakers.

[0018] This means that at speeds below, for example, 30 km / h or 50 km / h, the system automatically switches to the speakers in the head area and / or at least activates a filter. The driver or passenger can, of course, deactivate this adaptive function if desired.

[0019] To optimize acoustic decoupling, the critical coupling frequency ranges are determined through measurement. The audio output is then modified using digital filters such as low-pass, high-pass, band-pass, or notch filters to attenuate the signal levels in these critical frequency ranges. This ensures that nothing is audible outside the vehicle.

[0020] One example of implementing the invention is that, depending on the vehicle speed, the system automatically switches between the speakers in the head area of ​​the seat and / or the filtered telephone signal during hands-free calling, in order to achieve acoustic decoupling from the outside. This adaptive function can also be activated or deactivated by the user independently of the speed via a switch, button, or toggle.

[0021] This solution offers an innovative approach to reducing the acoustic transmission of audio output from the vehicle interior to the exterior. By using speakers in the head area and / or digital filtering, acoustic decoupling is achieved without the need for complex soundproofing or acoustic decoupling systems. This provides improved privacy and enhanced data protection for the vehicle's occupants. The acoustic transmission reduction method offers an effective and user-friendly solution for adjusting the audio output to the vehicle's speed and ensuring optimal acoustic decoupling at low speeds.

[0022] Fig. Figure 1 shows a device (10) according to the invention. The device (10) comprises a control unit (11) configured to automatically change the audio output (15) depending on the vehicle speed. The control unit (11) is configured to filter an audio signal for the audio output (15) by means of a signal processor (13) in order to attenuate certain frequency ranges and / or to control a specific output unit (14) of the vehicle.

[0023] For example, the control unit (11) switches to the digitally filtered audio signal depending on the vehicle speed. Furthermore, depending on the vehicle speed, the control unit (11) can act as an output unit (14) and control loudspeakers in the head area of ​​a seat (16) of the vehicle, switching the audio signal output to the loudspeakers depending on the vehicle speed.

[0024] Naturally, a combination of both approaches is also possible. On the one hand, the audio output (15) can be changed by switching it to the output unit (14) in the head area of ​​the seat (16), and on the other hand, the audio output can be filtered using the signal processor (13). The audio signal can be a telephone signal, and the audio output (15) a telephone conversation. To filter the audio signal, the signal processor (13) can use low-pass, high-pass, band-pass, or notch filters to attenuate the critical frequency ranges.

[0025] The control unit (11) can change the audio output (15) in stages or continuously depending on the vehicle speed and can make the change of the audio output (15) deactivatable by the driver or passenger.

[0026] The device (10) can be part of an infotainment system (10) of the vehicle and the control unit (11) can change the audio output (15) depending on the vehicle speed and / or the vehicle condition.

[0027] In a first embodiment, the control unit (11) detects the current vehicle speed via a speed sensor (12). Based on this, the signal processor (13) filters the audio signal for the audio output (15) of a telephone call, in particular to attenuate the critical frequency ranges. The control unit (11) switches to the digitally filtered audio signal when the vehicle speed falls below the threshold value for vehicle speed and / or is within the speed range.

[0028] In a second embodiment, the control unit (11) controls the loudspeakers (14) in the head area of ​​the seats depending on the vehicle speed. At a vehicle speed below the threshold and / or within the speed range, the audio output (15) of the telephone call is then amplified and output via these loudspeakers (14) in the head area of ​​the seat in order to reduce transmission to the outside.

[0029] Fig.Figure 2 schematically illustrates the method according to the invention. In a first step S10, the current vehicle speed is detected. In the second step S20, it is checked whether the vehicle speed falls below the threshold value for vehicle speed and / or is within the speed range. If this is not the case (path N), the current vehicle speed continues to be detected. If the vehicle speed is below the threshold value for vehicle speed and / or within the speed range (path J), then in a third step S30, the audio output is automatically modified depending on the detected vehicle speed, by filtering the audio signal for audio output and / or by controlling a specific output unit of the vehicle in a fourth step S40.

[0030] The intensity of acoustic coupling to the vehicle body or other vehicle components is frequency-dependent. The frequency range that most strongly couples to the body depends on many factors, such as the geometry, speaker mounting locations, and materials. Therefore, the critical frequencies are preferably determined through measurement. Once these critical frequency ranges have been identified, the audio signal is modified using digital filters (FIR, IIR filters) to attenuate the signal levels of the critical frequencies to such an extent that they are no longer audible outside the vehicle. This essentially results in frequency shaping to achieve acoustic decoupling.

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