Vehicle cabin simulation for audio tuning and testing

Abstract

The invention relates to vehicle cabin simulation for audio tuning and testing. A method of simulating a vehicle cabin for audio tuning and / or testing and a corresponding system, the method comprising obtaining (17) and storing (20) 3D impulse responses corresponding to individual loudspeakers in the vehicle cabin to be simulated. At a location remote from the vehicle, a multi-channel input audio stream (22) is generated and the individual channels are processed (23) by a real-time convolution process to create an audio stream in surround sound format as output. An audio stream output (24, 32), e.g. In a panoramic sound format, may be decoded (33) and played back in the audiometry room so that a tuning engineer may adjust parameters of the input audio stream (22, 28) delivered in real time to the simulated environment listening experience. In this way, the parameters can be optimized and applied back to the sound system of the real-world vehicle.

Description

Technical Field

[0001] The present disclosure relates to the field of tuning and testing audio systems in vehicles. In particular, the present disclosure relates to simulating acoustic characteristics from within a vehicle cabin to enable configuration of an audio system for a real-world vehicle corresponding to the simulated vehicle cabin. Background Art

[0002] It is known that tuning and testing audio systems in automotive cabins is complex and time-consuming. Tools are available for remote sound tuning in vehicles, for example, by simulating the cabin impulse response, a set of preliminary parameters can be defined, which significantly reduces the time spent on actual in-vehicle tuning. However, simulation of multi-channel automotive audio systems is problematic.

[0003] One known solution is based on offline adjustment of the gain, equalization, and delay of specific speakers. However, it is not possible to listen to the presets generated in the automotive cabin externally (i.e., in a separate listening environment that is not the vehicle itself). This implementation will only show the effect of the tuning parameters on the previously measured impulse response.

[0004] Another tool provides a similar opportunity for remote calibration, allowing preprocessing of an input audio file to produce an audible output that can be listened to on headphones for all automotive speakers together. This solution uses a mono cabin impulse response measurement combined with a generic HRTF (head-related transfer function) for auditoryization (i.e., simulated acoustic experience in virtual space). Summary of the Invention

[0005] In view of the above, the present invention seeks to address the disadvantages associated with known simulation solutions or at least provide an alternative practical method to those skilled in the art.

[0006] Now, a first aspect of the present invention is outlined. For example, a method for simulating a vehicle cabin for audio tuning and testing is described herein, the method comprising the steps of: recording the 3D impulse response of each speaker to be tuned within the vehicle cabin using a microphone (e.g., a set of microphones and encoding means); storing the impulse response; at a location remote from the vehicle, playing back / sending (e.g., generating or obtaining / acquiring (source)) a multi-channel audio stream and performing real-time convolution processing on each channel of the audio stream based on the corresponding 3D impulse response; and outputting the audio stream.

[0007] An example of a multi-channel / global surround sound format is Ambisonics, for example obtaining a signal stored in B-format. An example of a first-order Ambisonics microphone is the Zoom H3-VR recorder, which includes four spaced-apart microphones for capturing sound in multiple directions. In a known manner, impulse responses are obtained by playing test tones (such as sine sweeps) through each speaker in the vehicle cabin and capturing the test tones with appropriate hardware.

[0008] In one embodiment, at least one predetermined position includes the driver position / head level height. However, this can further include multiple predetermined positions corresponding to passenger positions.

[0009] In this way, accurate acoustical reproduction of the vehicle cabin can be achieved on any audio system or headphones away from the vehicle. Real-time multi-channel processing can be performed directly on the target hardware, such as the vehicle's audio control unit or a PC-based application.

[0010] According to the disclosed method, all audio blocks can be tuned, not just gain, delay, and equalization. In addition, testing of complex audio algorithms is possible, such as ANC (active noise cancellation), 3D effects, etc.

[0011] In an embodiment, the real-time processing is integrated with the vehicle's own in-vehicle audio software / framework, which is typically provided to the OEM to adapt to different cabin environments and vehicle configurations. Such a solution can span the entire audio software stack, including DSP (digital signal processing), audio management, control logic, and tuning and calibration functions. By centralizing the audio processing in the driver's seat range controller instead of the audio nodes, it is possible to fully integrate the embedded real-time software and eliminate the need for external units for audio processing, resulting in cost reduction. The system for calibration according to the present disclosure can be an analog system (e.g., having the same processing blocks as the in-vehicle system) or the real system itself.

[0012] In an embodiment, the output sound format (e.g., a general immersive output format in Ambisonics B-format) can be decoded in real time at the endpoint audio system. For example, in a multi-speaker listening room, where experienced automotive audio tuning engineers can listen to an audio reference track (e.g., a familiar music segment) enhanced by the output sound format and adjust its parameters. The engineers listen for sound imbalances and unwanted resonances in order to eliminate them subsequently during playback.

[0013] Adjustments made by an engineer can be stored in a suitable format to provide an instruction set output for implementation in an in-vehicle sound controller of a real-world vehicle to optimize its speaker system. For each vehicle cabin specification and speaker system combination, a separately tuned solution is typically desired. The present invention enables real-time processing of 3D sound, thus allowing the engineer to experience the changes he / she has made.

[0014] The present invention can be applied not only to automotive cabins, but also to other vehicle spaces to generate their acoustic simulations. In fact, for tuning and / or testing purposes, the core concept can be applied to sound reproduction in any space (enclosed or otherwise). BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Exemplary embodiments will now be described with reference to the drawings, in which:

[0016] Figure 1 A measurement sequence is schematically shown;

[0017] Figure 2 A simplified process flow diagram is schematically shown; and

[0018] Figure 3 A more detailed process flow diagram is schematically shown. DETAILED DESCRIPTION

[0019] The following description provides exemplary embodiments and is used in conjunction with the appended Figure 1 to explain the principles of the present invention. However, the scope of the present disclosure is not intended to be limited to the exact details of the embodiments or an exact correspondence with all features and / or method steps, as variations will be apparent to those skilled in the art and are also considered to be covered by the specification. The terms used herein for components should be given a broad interpretation, which also includes equivalent functions and features. In some cases, several alternative terms (synonyms) have been provided for structural features, but these terms are not intended to be exhaustive. Descriptive terms should also be given the broadest interpretation; for example, the term "comprising" used in this specification means "consisting at least in part of...", such that every statement in this specification that includes the term "comprising" can also have features other than the features that begin with that term. Related terms such as "including" and "comprising" are interpreted in the same way.

[0020] The description herein relates to embodiments having a specific combination of steps or features, however, further combinations and cross-combinations of compatible steps or features between embodiments are envisioned to be possible. In fact, the separate features can act independently of other features as aspects of the present invention and do not necessarily require implementation as a complete combination.

[0021] It should be understood that the illustrated embodiments show applications for illustrative purposes only. In fact, the present invention can be applied to many different configurations, and the embodiments are directly implementable by those skilled in the art.

[0022] As described in the background art section above, real-time simulation of a multi-channel in-vehicle audio system according to existing methods is not possible or at least very limited. Instead, by using 3D impulse response measurement and real-time convolution, the present disclosure enables the reproduction of the measured audio system, i.e., a virtual version of the vehicle cabin, on any multi-channel speaker configuration (such as a 5.1 system or headphones) outside the vehicle. Depending on the actual implementation, an ambisonic microphone or a recorder such as H3-VR can be used to perform in-cabin measurements.

[0023] The integration of this concept with existing vehicle audio frameworks (e.g., the applicant's Aptiv audio framework) allows for the real-time simulation and tuning of the corresponding audio signals on a PC or a hardware setup outside the vehicle.

[0024] Furthermore, the implementation of the solution described here as an output block of a vehicle audio framework provides an opportunity to tune other processing blocks, such as compressors, limiters, or third-party algorithms, not just the EQ, gain, and delay that are typically adjusted by tuning engineers. Additionally, other algorithms such as active noise cancellation and 3D effects can be tested with the proposed algorithm on any multi-channel, reference audio system.

[0025] Figure 1 A measurement sequence is schematically shown. For example, the measurement tool 11 application can be activated on the PC in step 12, where the speaker configuration (or customization) is specified from a common option list in 13.

[0026] The measurement tool 11 interacts with the vehicle hardware 14 controlled by software configured for the vehicle model. The measurement tool initiates a measurement signal (e.g., a sine sweep) 15 via the vehicle hardware for measuring the impulse response of the first speaker. At the same time, the recorder 16 (e.g., an ambisonic recorder device with a set of microphones) starts recording the sine sweep 17 and captures the audio data to be transmitted 18 back to the measurement tool 11 when the sine sweep terminates.

[0027] The microphone array can be located at the first head position of a vehicle passenger, e.g., at the driver's seat.

[0028] Step 19 represents the audio data processing of the signal captured from the cabin by the measurement tool 11 and the calculation of the impulse response, followed by an export function 20, i.e., the resulting impulse response is exported from the measurement tool for later use in cabin simulation.

[0029] The measurement sequence should be repeated for all cabin speakers indicated by reference numeral 21. Each recording is typically a separate file, but all sources can be recorded in unison and output together.

[0030] The complete speaker setup can also be recorded from an alternative location in the cabin, corresponding to other passenger positions, in the order described above.

[0031] Figure 2 A simplified illustration of how to utilize the resulting 3D impulse response at a location remote from the target vehicle is shown. For example, block 21 represents a multi-channel audio endpoint (or "receiver", e.g., the endpoint where signals from different audio sources are routed), which is functionally equivalent to a sound system and control software / platform from which vehicle audio can be played back. The thick arrow 22 represents the multi-channel audio stream of the reference track routed to the cabin simulation function block 23 (i.e., the simulated receiver), where the convolution of each channel is processed with the corresponding 3D impulse response of a specific speaker. In the exemplary form described here, the output 24 is a B-format audio stream. After decoding, the output audio stream 24 can be played back in real time in an anechoic chamber (or headphones) that effectively reproduces the acoustic space of the vehicle. Then, the control software can be adjusted at block 21, which is commonly referred to as "tuning". Any capabilities of the vehicle audio system can be tested through the simulated space, enabling an accurate evaluation (audition) of all functions without the need to be present at the test vehicle.

[0032] Figure 3 An alternative representation of the processing flow is shown, particularly showing how the method enables integration with an existing vehicle audio system control platform.

[0033] represented as "Aptiv TM Audio DSP Framework" 25, the vehicle audio system can include general audio processing at block 26, which receives the input audio signal 27 and can adjust the playback 28 of the audio signal 27 through tuning parameters 29. Within the DSP platform 25, the cabin simulation block 30 configured according to the input cabin measurement data 31 obtained in Figure 1 processes the audio stream output 32 (i.e., in panoramic B format) for transmission to the decoder 33 and subsequent output audio stream 34 in a multi-speaker anechoic chamber (preferably) or via headphones.

[0034] Changes to the tuning parameters of the platform and / or any 3D effect or functional processing capabilities can be carried through the entire chain to be simulated for evaluation by the engineer. Modifications to the parameters are audibly available to the engineer in real time. When the audio experience has been optimized (i.e., the tuning parameters have been determined), these tuning parameters can be stored in a suitable format for uploading to the audio system platform of a real-world vehicle. Multiple optimizations can be stored for end-user selection.

[0035] In summary, the present invention is embodied by a method and corresponding system for simulating a vehicle cabin for audio tuning and / or testing. The method can include, for example, obtaining and storing 3D impulse responses corresponding to each speaker within the cabin of the vehicle to be simulated by recording. At a later time and away from the vehicle, a multi-channel input audio stream can be obtained and sent in real time, and each channel can be processed by any convolution processing according to the corresponding speaker to create an audio stream in surround sound format. For example, an audio stream in Dolby Atmos format can be decoded and played back in an anechoic chamber (or via headphones) such that the tuning engineer can adjust the parameters of the input audio stream that is being delivered in real time to the simulated environmental listening experience. In this way, the parameters can be optimized and applied back to the audio system of a real-world vehicle.

Claims

1. A method of simulating a vehicle cabin for audio tuning and / or testing, the method comprising the following steps: Obtaining and storing 3D impulse responses corresponding to respective speakers within a cabin of a vehicle to be simulated; applying convolution processing to each channel of a multi-channel audio stream in real time based on the corresponding 3D impulse response at a location remote from the vehicle; as well as Output surround sound format audio stream.

2. The method of claim 1, further comprising decoding the surround sound format audio stream for playback.

3. The method according to claim 2, wherein: Perform playback in a multichannel audiometry booth or over headphones.

4. The method according to any one of claims 1 to 3, wherein: The input audio stream is generated by a vehicle sound system platform corresponding to a vehicle sound system platform of the vehicle.

5. A method according to any one of claims 1 to 4, comprising the step of adjusting an input audio stream according to at least one parameter affecting the audio, wherein: The adjustment to the at least one parameter is reproduced in real time in the output audio stream.

6. The method according to claim 5, wherein: The at least one parameter is selected from any one of: gain; equalization; delay; compressor; limiter; active noise cancellation; and 3D effect.

7. The method according to any one of claims 1 to 6, wherein: The obtaining step is performed by recording the 3D impulse response with a surround sound microphone set.

8. The method according to any one of claims 1 to 7, wherein: The obtaining step is performed from at least one predetermined position within the cabin, and a set of impulse responses is stored according to the predetermined positions.

9. The method according to claim 8, wherein: The at least one predetermined position is the position of the driver.

10. A system for performing the method of simulating a vehicle cabin for audio tuning and / or testing according to any one of claims 1 to 9, the system comprising: Vehicle sound system hardware for sending a multi-channel input audio stream and applying convolution processing to the multi-channel input audio stream.

11. The system according to claim 10, further comprising a decoder for decoding the surround sound format audio stream.

12. The system according to claim 11, wherein: The decoder is configured to decode an Atmos format.

13. The system of claim 11 or 12, further comprising multi-channel audio room hardware or headphones for playing back the decoded surround sound format audio stream.

14. A non-transitory computer readable medium containing instructions which, when executed by one or more processors, implement or facilitate the method of any one of claims 1 to 8.

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