Method for masking disturbing noises, and vehicle

Abstract

The invention relates to a method for masking undesired disturbing noises (3), generated by a drivetrain (1) of a vehicle (2), by means of synthetic noises (26), wherein: at least one synthetic noise (26) is output by means of at least one loudspeaker (4) in the vehicle interior; a noise signal (11) representing the synthetic noise (26) passes through a bandpass filter (5) and undergoes a level adjustment before being output in the vehicle interior; and parameters of the bandpass filter (5) and the level adjustment are implemented in accordance with a drivetrain rotational speed (8). The method according to the invention is characterized by the following method steps: - providing a disturbing noise characteristic map (6), comprising a relationship between the frequency band (7), the level and the drivetrain rotational speed (8), for each disturbing noise (3) that can be emitted by the drivetrain (1); - generating a sound signal (12) comprising a sinusoidal sound with a frequency modulation applied thereto, wherein the center frequency of the sound signal (12) corresponds to the average frequency (9) of a disturbing noise (3), which is to be masked, from the disturbing noise characteristic map (6); - generating a defined-noise signal (13) comprising pink noise, wherein the frequency band of the pink noise comprises at least the lowermost and uppermost frequency of the disturbing noise (3) to be masked; and - mixing the sound signal (12) and the defined-noise signal (13) by means of a crossfader (10) to generate the noise signal (11).

Description

[0001] 2023P03496WQ

[0002] 1

[0003] Mercedes-Benz Group AG

[0004] Methods for masking background noise and vehicle

[0005] The invention relates to a method for masking unwanted noise generated by a vehicle's drive train by synthetic noises of the type defined in more detail in the preamble of claim 1, and to a vehicle equipped for carrying out the method of the type defined in more detail in the preamble of claim 8.

[0006] Vehicles such as cars can emit disturbing noises during operation. Such noises should ideally be imperceptible to the vehicle occupants in order to avoid negatively impacting user comfort.

[0007] Especially in electric vehicles, powertrain components such as the electric motor and transmission contribute to a corresponding acoustic excitation. The noises generated in this way are characterized by a tonal quality. Due to the often high frequency of the sinusoidal oscillations, such sounds are perceived as howling or whistling noises. Furthermore, there is a strong correlation between the rotational speed of the powertrain or the vehicle's speed and the frequency of the howling. Such howling noises also tend to attract the attention of the vehicle occupants, thus negatively impacting their perception of the vehicle's quality.

[0008] German patent application DE 102020 004 974 A1 discloses a method for masking unwanted noise generated by a vehicle's powertrain. To mask the unwanted noise, synthetic sounds are emitted via loudspeakers in the vehicle interior. Using a signal filter and an amplifier, a signal representing the synthetic sound is filtered or its volume adjusted before being emitted into the vehicle interior. The way the signal is processed depends on the powertrain speed and / or the magnitude of a load torque acting on the powertrain. The pitch of all acoustic signals in the synthetic sound remains constant. A broadband noise source is preferably used as the signal source.The broadband noise source is particularly capable of providing an output signal that resembles wind noise and / or a tire rolling on a surface. However, a disadvantage is that, due to its sound, the synthetic noise is only suitable for masking unwanted noise at relatively high drivetrain speeds.

[0009] Furthermore, DE 102018 109 937 A1 discloses active tone desensitization for tonal noises in a vehicle. A microphone located in the vehicle interior records a sound map of the acoustic environment inside the vehicle while it is in operation. Several uncorrelated broadband tone profiles are derived from this sound map. These broadband tone profiles are then randomly distributed to the vehicle's loudspeakers. Before being output via the loudspeakers, the signals are filtered using a band-limiting filter. The volume of the sounds output via the loudspeakers can be specifically adjusted.

[0010] DE 102021 004 108 B3 describes a method for masking vehicle noise by synthetic noises generated by multiplying an unmodulated noise with a filter- or amplifier-dependent vehicle parameter, whereby the pitch of the acoustic signals remains constant.

[0011] EP 3 514 790 A1 describes a system for generating masking sounds in vehicles, including electric vehicles, wherein a processor modulates the high-frequency range of a synthetic sound, while the low-frequency range remains unmodulated and outputs a combined sound based on vehicle operating parameters.

[0012] US 10629,182 B1 describes a method and system for adaptive noise masking in a vehicle, comprising determining the frequency and amplitude of powertrain and background noise, dynamically generating a masking audio signal based on these characteristics, and outputting the signal via interior speakers. The present invention aims to provide an improved method for masking unwanted noise emitted by a vehicle's powertrain.

[0013] According to the invention, this problem is solved by a method for masking unwanted noise generated by a vehicle's powertrain using synthetic noise with the features of claim 1. Advantageous embodiments and further developments, as well as a vehicle for carrying out the method, are described in the dependent claims.

[0014] A generic method for masking unwanted noise generated by a vehicle's powertrain by means of synthetic noises, wherein at least one synthetic noise is output via at least one loudspeaker in the vehicle interior, wherein a noise signal representing the synthetic noise passes through a bandpass filter and undergoes level adjustment before output in the vehicle interior, wherein parameters of the bandpass filter and the level adjustment are implemented as a function of a powertrain speed, is further developed according to the invention by the following method steps:

[0015] - Providing a noise characteristic map, comprising a relationship between the frequency band, the level and the drive train speed, for each noise emission from the drive train;

[0016] - Generating an audio signal comprising a sine tone with an imprinted frequency modulation, wherein the center frequency of the audio signal corresponds to the center frequency of a noise to be masked from the noise characteristic field;

[0017] - Generating a noise signal comprising pink noise, wherein the frequency band of the pink noise includes at least the lowest and highest frequencies of the noise to be masked; and

[0018] - Mixing the audio signal and the noise signal with a crossfader to generate the noise signal.

[0019] Using the method according to the invention, synthetic sounds can be generated that blend into the acoustic behavior of the vehicle and thus reliably and pleasantly mask typical drivetrain whine noises for the vehicle occupant. The synthetic sound(s) are not based on wind or rolling noise, but are optimized for their psychoacoustic effect. This means that masking of the unwanted noise is possible even at a lower volume or level of the synthetic sound. Furthermore, the synthetic sounds are more pleasant for the vehicle occupants. As mentioned at the outset, synthetic wind and rolling noises are only suitable for masking unwanted noise in a range of relatively high drivetrain speeds or vehicle speeds.This is primarily because perceptible wind and roll noises only occur at higher speeds. However, the inventive method also allows synthetic noises to be generated and output in the vehicle interior, masking unwanted noises at lower drivetrain speeds or vehicle speeds. This enables the masking of unwanted noises across a broad frequency range, including, in particular, howling noises from 100 Hz up to over 3000 Hz. Furthermore, the inventive method minimizes side effects that arise during the generation of the synthetic noises, such as the increase in the overall noise level in the vehicle interior.

[0020] The components required to carry out the method according to the invention are typically found in modern vehicles, so that the method according to the invention can be implemented quickly and easily in the respective vehicles.

[0021] By means of level adjustment, the volume of the synthetic noise can be adjusted so that the synthetic noise is only perceptible when corresponding background noise is also present. Using the method according to the invention, the synthetic noises can be specifically tuned to the respective whine frequency to be masked. The synthetic noises are subjectively embedded in the existing operating noises of the vehicle and are therefore not perceptible to the human ear as synthetic, i.e., artificially generated, noises. This creates an authentic user experience when operating the vehicle. By masking the background noise, additional acoustically effective components can be designed more simply or even eliminated entirely. These include, for example, means for actively combating noise, vibration, and harshness (NVH).Depending on the vehicle's speed and the drivetrain speed (i.e., the rotational speed of a drivetrain component), the vehicle can generate various noise disturbances. The vehicle manufacturer can record the vehicle's acoustic behavior in a measurement campaign. This measurement campaign allows the generation of a noise disturbance map. The noise disturbance map can be stored as digital data in a physical storage medium within a computing unit in the vehicle. The noise disturbance map describes the acoustics in the vehicle interior, indicating which frequencies occur at what volume levels, depending on the drivetrain speed. A noise disturbance is present when the level of certain frequencies exceeds a specific threshold. Using the method according to the invention, corresponding synthetic noises can be generated for all occurring noise disturbances.

[0022] During vehicle operation, it can happen that several unwanted noises occur simultaneously at a specific drivetrain speed. These can be masked simultaneously. For this purpose, several synthetic noises are emitted via the loudspeaker(s) in the vehicle interior. Preferably, each synthetic noise is distributed across multiple loudspeakers to make it more difficult for a vehicle occupant to pinpoint the exact source of the noise.

[0023] The bandpass filter settings, i.e., the upper and lower limits for the frequency components allowed through the filter, as well as the level adjustment, are determined based on the drive train speed. This ensures that synthetic noise is only output within the speed and frequency ranges where corresponding noise is present. The noise characteristic map indicates the speed range in which a particular noise occurs and the frequency components it contains. For this speed range, the corresponding frequencies are allowed through the bandpass filter. Lower and higher frequencies can also be allowed through proportionally to mask the noise more broadly. The audio signal can then be used to reliably mask the noise.The audio signal undergoes frequency modulation, so that its frequency oscillates around the center frequency of the noise to be masked, changing with a defined frequency deviation. This helps ensure that the synthetic noise is not perceived as disturbing, even by individual vehicle occupants.

[0024] To further improve the integration of the synthetic noise into the vehicle's acoustic soundscape, pink noise is superimposed on it. Due to its decreasing level with increasing frequency, pink noise sounds more pleasant to humans than, for example, white noise or broadband noise. The frequency band of the pink noise encompasses at least the lowest and highest frequencies of the noise to be masked. Preferably, however, the pink noise also includes lower and higher frequency components. In particular, the lower and upper limits of the pink noise frequency band are chosen to be large enough to include all frequency components of all noise emitted by the powertrain. Thus, the pink noise only needs to be generated once and can be used to mask all noise.

[0025] A crossfader is a common component used to manipulate audio signals. It can also be called a "blender." The crossfader allows the audio signal and noise signal to be mixed to create the sound signal. The crossfader can be implemented on a processing unit within the vehicle and can be implemented using hardware and / or software components. The proportion of the audio signal and noise signal in the sound signal can be adjusted between 0 and 1 using the crossfader. The sound signal can therefore consist solely of the audio signal, solely of the noise signal, or, preferably, at least partially of both.

[0026] For different types of noise, a different mixing ratio between the audio signal and the noise signal can be set. This allows the synthetic noises to be even better adapted to the specific noises being masked. The respective noises can be assigned to different orders within the noise map. The noise map can be represented, for example, by a diagram where the abscissa represents the drivetrain speed or vehicle speed, and the ordinate represents the frequency of the respective noise perceptible in the vehicle interior or emitted by the drivetrain. The noise map also includes the level as a third parameter, which can be represented, for example, by different colors in the diagram. Noises of the same order then lie on a common line in the diagram. This line can be straight or curved.As the order of the curve increases, so does the slope of the corresponding lines in the diagram. Particularly advantageous is the masking of unwanted noises present over a wide speed range in this diagram or noise map by multiple synthetic noises. For example, the speed range of an unwanted noise can be divided into three equal sections, with an individual synthetic noise generated for each section. The respective synthetic noises can also be superimposed at their respective speed limits, thus blending seamlessly into one another. This results in even better masking.

[0027] An advantageous further development of the method according to the invention provides that the frequency deviation of the frequency modulation applied to the sine tone is at least twice as large as the frequency band of the noise to be masked. This improves the reliability with which the respective noises can be masked. The bandpass filter can then be adjusted accordingly to allow the respective frequency components to pass through.

[0028] According to a further advantageous embodiment of the method according to the invention, the modulation frequency of the frequency modulation applied to the sine tone is further provided that it lies between 15 Hz and 300 Hz and / or that the modulation frequency is varied depending on the drive train speed. The modulation frequency denotes the interval between the respective pitches that the sine tone oscillating from the audio signal through frequency modulation is intended to assume. The pitch can thus be adjusted in fine or coarse steps. The modulation frequency can be fixed. Synthetic sounds for various noises can have different, individual modulation frequencies. The modulation frequency can also be varied depending on the drive train speed, which allows for even more reliable masking of the noises.

[0029] A further advantageous embodiment of the method according to the invention provides that the parameters of the bandpass filter are adjusted taking into account the order of the noise to be masked in the noise characteristic map, wherein, in particular, a masking order is selected which is lower than the order of the noise to be masked. In other words, the section frequencies of the bandpass filter are dynamically adjusted as a function of the instantaneous drive train speed multiplied by the masking order. Preferably, the masking order corresponds at most to the whine order, i.e., the order of the noise to be masked, but can be chosen to be somewhat "flatter" for a more psychoacoustically pleasing sound. Thus, if, for example, the whine order is 48, a masking order of 42 can be selected.The resulting perceptible slope of the frequency over the change in rotational speed becomes flatter, resulting in a more pleasant and higher-quality driving sound.

[0030] According to a further advantageous embodiment of the method according to the invention, it is further provided that the filter quality of the bandpass filter is manually adjusted according to a user setting or that the filter quality of the bandpass filter is automatically adjusted depending on a predefined parameter, in particular in correlation with the drive train speed. The bandwidth of the bandpass filter can be adjusted via the filter quality. Thus, with decreasing filter quality, the upper cutoff frequency of the bandpass filter is shifted to higher frequencies and the lower cutoff frequency to lower frequencies, and vice versa with increasing filter quality. With a low filter quality setting, broad and airy masking noises or synthetic noises can be generated, which not only mask the frequency components contained in the respective noise but also secondary frequency ranges.A high filter quality setting allows for the creation of narrowband masking noises. The filter quality must not be set too high, otherwise the resulting masking noise would itself be perceptible as a howling sound.

[0031] Vehicle occupants can be given the option to adjust the filter quality themselves. This allows for a better adaptation to individual user preferences. In this way, it becomes even more reliable to mask disturbing noises perceived by vehicle occupants.

[0032] A further advantageous embodiment of the method according to the invention provides that the level of the synthetic noise to be emitted in the vehicle interior is increased from a first target level to a second target level in a speed range before the occurrence of a noise to be masked, and reduced from the second target level back to the first target level in a speed range after the occurrence of the respective noise to be masked. In other words, a respective synthetic noise can thus be introduced before the occurrence of a noise and faded out again after the noise has ceased. The first target level therefore describes a volume that is not or almost not perceptible to a vehicle occupant. The second target level, on the other hand, describes a volume at which a corresponding noise reaches the volume necessary to mask the howling noise.The level can be constantly varied between the first and second target levels as a function of the drivetrain speed. The volume thus increases or decreases uniformly with the drivetrain speed. It is also possible to change the volume progressively or degressively. The respective speed ranges in which the volume of the synthetic noise is increased or decreased therefore seamlessly follow the speed range in which the noise occurs. The level of the synthetic noise, i.e., its volume, can be kept constant during its output or also varied. For example, the volume can be increased with increasing drivetrain speed until the center frequency of the noise is reached and then decrease. The volume can also oscillate continuously.The raising and lowering of the level in the speed range in which a disturbance noise is present can be carried out linearly, follow a sinusoidal oscillation, or be carried out randomly.

[0033] According to a further advantageous embodiment of the method according to the invention, the synthetic sound, in the form of a sound object within a virtual sound field, is placed at a desired position in the vehicle interior, particularly using an ambisonics algorithm. This creates an even more natural sound experience for the respective vehicle occupants. In particular, it is 2023P03496WQ

[0034] 10. This makes it more difficult to pinpoint the exact sound sources of the synthetic noises. Therefore, the signal propagation times and frequency responses of the synthetic noises can be adjusted to create a spatially defined sound. By creating the synthetic noise as a sound object, it can be virtually placed at any desired position within the vehicle interior. The synthetic noise can be particularly effectively positioned between the respective vehicle occupant, such as the driver, and the source of the unwanted noise, for example, the installation location of an electric drive motor. The varying intensity of the masking noise at different seating positions in the vehicle can also be influenced by the positioning of the sound objects. This allows for even more reliable masking of unwanted noises.Furthermore, vehicle occupants perceive the sound field emitted within the vehicle interior as particularly pleasant. Using established Ambisonics algorithms to generate the virtual sound field, corresponding synthetic sounds in the form of sound objects can be quickly and easily placed within the vehicle interior.

[0035] The target position can also be changed over time. To ensure that a specific synthetic sound is perceived as being placed at a particular target position, the synthetic sound is output to the different loudspeakers with a varying delay. This delay can oscillate over time.

[0036] In a vehicle comprising a processing unit, a sensor for detecting the drivetrain speed, and at least one loudspeaker for emitting sound into the vehicle's interior, the processing unit, the sensor, and the at least one loudspeaker are, according to the invention, configured to carry out a method described above. The vehicle can be any road vehicle, such as a car, truck, van, bus, or the like. Generally, it could also be a rail vehicle, watercraft, or aircraft.

[0037] The computing unit has at least read access to a computer-readable storage medium containing machine-interpretable instructions which, when executed by a processor of the computing unit, cause the processor to provide the corresponding steps of the method according to the invention. The vehicle's noise map can also be stored on the computer-readable storage medium. This enables the vehicle to quickly read the noise map.

[0038] Preferably, the vehicle has an electrified or partially electrified powertrain. The vehicle can therefore consist exclusively of electric motors as its drive unit. It is also possible that at least one internal combustion engine is present as a drive unit. The electricity required to operate the electric motors can be drawn from a traction battery or from a fuel cell system. The vehicle can be a purely battery-electric vehicle or a so-called plug-in hybrid. The method according to the invention is particularly suitable for use in electrified vehicles to mask the whining or whistling noises emitted by electric motors.

[0039] Further advantageous embodiments of the inventive method for masking background noise and of the inventive vehicle also result from the exemplary embodiments, which are described in more detail below with reference to the figures.

[0040] This shows:

[0041] Fig. 1 shows a schematic representation of a vehicle according to the invention;

[0042] Fig. 2 shows a schematic representation of a noise characteristic curve;

[0043] Fig. 3 shows the noise characteristic curve from Fig. 2, in which noise is masked by synthetic noise; and

[0044] Fig. 4 shows a schematic representation of the generation of the synthetic sound using a method according to the invention.

[0045] Figure 1 shows a top view of a vehicle 2 according to the invention. The drive train 1 of the vehicle 2 emits disturbing noises 3 during operation. The drive train 1 includes, in particular, a drive unit 18, such as an internal combustion or an electric motor, a transmission (not shown in detail), the front axle 19, and the wheels 20 of the vehicle 2. Electric motors, in particular, tend to emit more or less audible whining or whistling noises at certain operating points. The perception of these disturbing noises 3 in the vehicle interior can be unpleasant for the vehicle occupants.

[0046] The vehicle 2 according to the invention is capable of masking corresponding interference noises 3 by means of synthetic noises 26 emitted via loudspeakers 4. These synthetic noises 26 are generated by a processing unit 16. It is particularly advantageous for the synthetic noises 26 to be realized in the form of sound objects 14 of a sound field, which are virtually placed at a target position 15 in the vehicle interior.

[0047] The occurrence of the respective disturbance noises 3 depends on a drive train speed 8 of a component of the drive train 1, as shown in Figure 2. This drive train speed 8 is detected by means of a suitable sensor 17. This allows the processing unit 16 to generate a synthetic noise suitable for the respective disturbance noise 3.

[0048] Figure 2 shows a noise map 6 derived for the vehicle 2. The noise map 6 can be recorded, for example, by the vehicle manufacturer through measurements in a test vehicle. In the noise map 6, the frequency 21 of the corresponding noises emitted by the powertrain 1 is plotted against the powertrain speed 8. A noise 3 is present when a critical loudness is exceeded for a given frequency 21 at the respective powertrain speed 8. The respective noises 3 can be assigned to different orders, with two order lines 22 representing such orders shown in Figure 2. For example, the order line 22 with the shallower slope can represent the first order, and the order line 22 with the steeper slope can represent the second order.

[0049] A given speed range 44 in which such a disturbance noise 3 is present begins at a certain starting speed 23 and ends at a certain final speed 24. For a disturbance noise 3, the level exceeds the aforementioned critical volume for frequencies 21 that lie within a frequency band 7 characteristic of the disturbance noise 3. Disturbance noises 3 that occur at high speeds, indicated in Figure 2 by a marker 25, can be masked by artificially generated wind-roll noises. However, with the aid of the method according to the invention, it is also reliably possible to mask the remaining disturbance noises 3 in a pleasant manner for the respective vehicle occupants.

[0050] For this purpose, as shown in Figure 3, the respective noises 3 are superimposed by synthetic noises 26. This is shown in Figure 3 as an example for the two first-order noises 3.

[0051] The mean frequency 9 of a given noise 3 coincides particularly advantageously with the center frequency of a corresponding synthetic noise 26. The masking order of the synthetic noises can be chosen to match the respective order of the noise 3 to be masked. In Figure 3, however, a smaller masking order is chosen, which can be seen from the fact that the slope of a gradient line 27 drawn through the respective synthetic noises 26 is smaller than the slope of the corresponding order line 22.

[0052] Figure 4 illustrates the procedure for generating corresponding synthetic noises 26. It shows an algorithm 28 executed by the processing unit 16. The algorithm 28 is executed individually for each noise 3. Therefore, multiple instances of the algorithm 28 can be executed simultaneously. Depending on the starting speed 23, the final speed 24, and the respective order 29 of the noise 3, a mean speed or speed range 44 and a corresponding masking frequency or frequency band 7 of the underlying noise 3 are determined in a block 30. This information is read from the noise characteristic map 6. A carrier frequency 31 is modulated using this masking frequency. This frequency modulation takes into account a modulation frequency 32 and a frequency deviation 33.A frequency-modulated oscillator 34 is used to generate an audio signal 12. The audio signal 12 comprises a sine wave with the aforementioned superimposed frequency modulation. The center frequency of the audio signal 12 corresponds to the center frequency 9 of the noise 3 to be masked, as defined in the noise characteristic curve 6. The frequency deviation 33 is preferably at least twice the frequency band 7 of the noise 3 to be masked. The frequency deviation 33 can also be equal to or smaller than the frequency band 7. Pink noise in the form of a noise signal 13 is provided by a source 35. The audio signal 12 and the noise signal 13 are mixed together using a crossfader 10. This creates a noise signal 11, which then passes through a bandpass filter 5 and undergoes level adjustment by means of an amplifier 36. The noise signal 11 can be subjected to cabin equalization in an equalizer 37.This involves a special filtering process that takes into account the acoustic properties of the vehicle interior or the loudspeaker system used.

[0053] The noise signal 11 is then mixed with an audio signal 38 and output via the loudspeakers 4. The audio signal 38 comprises the sounds that would otherwise be output via the loudspeakers 4 of the vehicle 2, such as music, radio, warning tones, acoustic navigation instructions from a vehicle-integrated navigation system, and the like.

[0054] Figure 4 also shows the sensor 17 and the drive train speed 8 provided by the sensor 17, from which a virtual masking frequency 41 is determined, taking into account a virtual order number 39 representing the masking order and the information obtained from block 30, in particular the speed range 44 and the frequency band 7 or the masking frequency. The bandpass filter 5 is parameterized based on the virtual masking frequency 41. For this purpose, the filter frequencies 40, in particular the upper and lower cutoff frequencies of the bandpass filter 5, are defined. The virtual masking frequency 41 thus defines the frequency band in which the corresponding synthetic noise 26 is to be output. A filter quality factor 42 of the bandpass filter 5 can also be set. Taking into account a characteristic map 43, the level boost can be adjusted as a function of the drive train speed 8 detected by the sensor 17.This allows the level to be raised for speed ranges 44 in which noise 3 is present and lowered outside of them.

[0055] Using the method according to the invention, the vehicle 2 according to the invention is able to generate synthetic sounds 26 to mask the unwanted noises 3. In this way, tonal powertrain noises that are perceived as undesirable can be masked. The overall noise level in the vehicle 2 is thus perceived by the vehicle occupants as more refined and less disturbing. The synthetic sounds 26 blend seamlessly into the noise level in the vehicle interior. The overall noise level in the vehicle interior increases only minimally. Moreover, the increase in the overall level is limited to the problematic speed and engine speed ranges. Numerous parameterization options are available for the generation of the synthetic sounds 26, allowing for fine-tuning to specific whining frequencies. Other measures to reduce unwanted noises 3, such as noise-vibration-harshness measures, are unnecessary.Furthermore, Algorithm 28 can be implemented quickly and easily in existing vehicles.

Claims

Mercedes-Benz Group AG Patent claims 1. A method for masking unwanted noise (3) generated by a powertrain (1) of a vehicle (2) by synthetic noise (26), wherein at least one synthetic noise (26) is output via at least one loudspeaker (4) in the vehicle interior, wherein a noise signal (11) representing the synthetic noise (26) passes through a bandpass filter (5) and undergoes level adjustment before being output in the vehicle interior, wherein parameters of the bandpass filter (5) and the level adjustment are performed as a function of a powertrain speed (8), characterized by the following method steps: - Providing a noise characteristic map (6) comprising a relationship between the frequency band (7), the level and the drive train speed (8) for each noise (3) emanating from the drive train (1); - Generating an audio signal (12) comprising a sine tone with an imprinted frequency modulation, wherein the center frequency of the audio signal (12) corresponds to the center frequency (9) of a noise to be masked (3) from the noise characteristic field (6); - Generating a noise signal (13) comprising pink noise, wherein the frequency band of the pink noise includes at least the lowest and highest frequencies of the noise (3) to be masked; and - Mixing the audio signal (12) and the noise signal (13) with a crossfader (10) to generate the noise signal (11).

2. Method according to claim 1, characterized in that the frequency deviation of the frequency modulation applied to the sine tone is at least twice as large as the frequency band (7) of the noise (3) to be masked.

3. Method according to claim 1 or 2, characterized in that the modulation frequency of the frequency modulation applied to the sine tone is between 15 Hz and 300 Hz and / or the modulation frequency is varied depending on the drive train speed (8).

4. Method according to one of claims 1 to 3, characterized in that the parameters of the bandpass filter (5) are adapted taking into account an order of the noise to be masked (3) in the noise characteristic map (6), wherein in particular a masking order is selected which is smaller than the order of the noise to be masked (3).

5. Method according to one of claims 1 to 4, characterized in that the filter quality of the bandpass filter (5) is manually set according to a user specification or the filter quality of the bandpass filter (5) is automatically set depending on a specification parameter, in particular in correlation to the drive train speed (8).

6. Method according to one of claims 1 to 5, characterized in that the level of the synthetic noise (26) to be emitted in the vehicle interior is raised from a first target level to a second target level in a speed range before the occurrence of a disturbance noise (3) to be masked, and is lowered from the second target level back to the first target level in a speed range after the occurrence of the respective disturbance noise (3) to be masked.

7. Method according to one of claims 1 to 6, characterized in that the synthetic noise (26) in the form of a sound object (14) of a virtual sound field is placed at a desired position (15) in the vehicle interior, in particular by applying an Ambisonics algorithm.

8. Vehicle (2) comprising a computing unit (16), a sensor (17) for detecting a drive train speed (8) and at least one loudspeaker (4) for emitting sound into the vehicle interior, characterized in that the computing unit (16), the sensor (17) and the at least one loudspeaker (4) are configured to perform a method according to one of claims 1 to 7.

9. Vehicle (2) according to claim 8, characterized by an electrified or partially electrified powertrain (1).

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