Automatic audio tuning system

Abstract

In accordance with an aspect of the present disclosure, there is provided an automatic audio tuning system comprising: a measurement engine to obtain a first measurement of one or more parameters associated with an audio signal from one or more speakers; an auto-tuning engine for receiving the first measurement and generating a tuning signal based on the first measurement; a signal stream integration engine for receiving the tuning parameters and generating one or more components of the signal stream, where each of the one or more components of the signal stream represents an audio parameter tunable based on the tuning signal; an audio signal processing engine for receiving one or more components of the signal stream and generating a playback audio signal based on the one or more components of the signal stream; and an evaluation engine for implementing evaluation of the playback audio signal.

Description

Technical Field

[0001] The present invention generally relates to an automatic audio tuning system. More specifically, the present invention relates to an automatic audio tuning system that can be used to optimize the sound output of multiple speakers in an audio system based on measurements of sound output and user input. The present invention can be applied to multimedia systems having speakers, such as multimedia systems in vehicles. Background Art

[0002] Multimedia systems such as vehicle audio / video systems, home theater systems, and home audio systems are well known. Such systems typically include multiple components, which include a sound processor that drives speakers with amplified audio signals. Multimedia systems can be installed with different components in various configurations. In addition, such multimedia systems can be installed in listening spaces of different sizes, shapes, and configurations. The components of the multimedia system, the configuration of the components, and the listening space in which the system is installed can all have a significant impact on the audio sound produced.

[0003] Once installed in a listening space, the system can be tuned to produce a desired sound field within the space. Tuning can include adjusting equalization, delay, and gain to compensate for the equipment and the listening space. Automatic sound field equalization is a well-known technique that helps to obtain a balanced listening experience and is widely demanded in the fields of vehicles, home theaters, and studios. During the process of sound field equalization or tuning, which is the commonly used equivalent term, it is necessary to collect measurement data as input for tuning, and evaluation is another key requirement for verifying the tuning results. However, known tuning tools do not provide a complete automatic tuning function chain. The object of the present invention is to address this need and provide an improved automatic audio tuning system. Summary of the Invention

[0004] According to the present disclosure, an end-to-end tool for automatic sound field equalization is provided. A typical application of automatic sound field equalization is in vehicles. The present disclosure focuses on applications in vehicles. Nevertheless, the present disclosure can also be applicable to other environments, such as rooms containing studios or home theaters or audio systems.

[0005] The present disclosure provides an automatic audio tuning system, which includes: a measurement engine for obtaining a first measurement of one or more parameters associated with an audio signal from one or more speakers; an automatic tuning engine for receiving the first measurement and generating tuning parameters based on the first measurement; a signal flow integration engine for receiving the tuning parameters and generating one or more components of a signal flow, wherein each of the one or more components of the signal flow represents an audio parameter that can be tuned based on the tuning parameters; an audio signal processing engine for receiving the one or more components of the signal flow and generating a playback audio signal based on the one or more components of the signal flow; and an evaluation engine for implementing an evaluation of the playback audio signal.

[0006] In an embodiment, the evaluation engine is configured to obtain a second measurement based on the playback audio signal based on one or more components of the signal flow, and / or the evaluation engine is configured to implement a subjective listening of the playback audio signal based on one or more components of the signal flow. Based on the objective and / or subjective evaluation results, the user decides to retune or make fine-tuning.

[0007] In another embodiment, the system includes a user interface configured to enable a user to adjust one or more tuning parameters, wherein the signal flow integration engine is configured to adjust the one or more components of the signal flow based on the tuning parameters adjusted by the user.

[0008] Therefore, the disclosed system implements a complete tuning function chain, starting from measuring the impulse responses of all speakers, automatic tuning, integration into the overall audio processing architecture (also known as the audio signal flow), to subjective and objective evaluation and subsequent manual fine-tuning. Based on the measured impulse responses and tuning configurations, tuning parameters can be generated. The user can decide whether to retune by reconfiguring the system or continue with fine-tuning based on subjective or objective verification.

[0009] Compared with conventional systems, the present disclosure can perform baseline tuning, such as tuning / adjusting equalization filters, time, and gain alignment, with less experience, expertise, time, and cost. Specifically, the present disclosure provides an end-to-end tool that automates the tuning process, thereby accelerating the tuning process and saving time to focus on subjective refinement beyond baseline tuning. In addition, the disclosed system can control any number of parameters / variables, thereby achieving a balanced listening experience, for example, between car seats. In addition, the disclosed system can make tuning more objective, thereby being more uniform in different cars or environments.

[0010] The system can be implemented by hardware, software, or a combination thereof. For example, the system can be implemented by instructions executable on a computer. In an embodiment, the system is implemented in a motor vehicle. Specifically, the system can be connected to or be part of an in-vehicle audio system.

[0011] The present disclosure also provides a method for tuning an audio signal, the method comprising: measuring one or more parameters associated with an audio signal from one or more speakers; generating tuning parameters based on the measured parameters; generating one or more components of a signal stream, wherein each of the one or more components of the signal stream represents an audio parameter that can be tuned based on the tuning parameters; generating a playback audio signal based on the one or more components of the signal stream; and evaluating the playback audio signal and, optionally, adjusting the tuning parameters (retuning) based on the evaluation, or performing fine-tuning. The user can also progress from fine-tuning to retuning. The method can include any of the features and functions described herein related to the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The features, objects, and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0013] Figure 1 The components and workflow of a system according to an embodiment of the present disclosure are schematically illustrated.

[0014] Figure 2 A measurement operation through the system according to an embodiment of the present disclosure is schematically illustrated.

[0015] Figure 3 A user interface of a system according to an embodiment of the present disclosure is shown, including speaker configuration and measurement parameters;

[0016] Figure 4 An automatic tuning process through the system according to an embodiment of the present disclosure is schematically illustrated.

[0017] Figure 5 A user interface for controlling the automatic tuning process through the system according to an embodiment of the present disclosure is shown;

[0018] Figure 6 A measurement response and a target curve of an audio system for the automatic tuning process through the system according to an embodiment of the present disclosure are shown;

[0019] Figure 7 Shows Figure 6 the tuning response and target curve of an audio system;

[0020] Figure 8Shows a signal flow with audio components generated by a system according to an embodiment of the present disclosure, where the audio components correspond to filters (in this case, biquadratic), delays, and gains;

[0021] Figure 9 Shows a biquadratic audio component in the user interface of a system according to an embodiment of the present disclosure;

[0022] Figure 10 Shows a display audio component in the user interface of a system according to an embodiment of the present disclosure;

[0023] Figure 11 Shows a gain audio component in the user interface of a system according to an embodiment of the present disclosure; Detailed Description

[0024] The present disclosure describes a system that provides a platform for automatically tuning an audio system. The system implements a complete tuning chain, including measurement, automatic tuning, signal flow integration, audio processing, and evaluation. Figure 1 Shows such a system 10 according to an embodiment of the present disclosure. System 10 includes a measurement engine 11 for measuring one or more audio parameters, such as the impulse response of one or more speakers of an audio system (not shown). The audio parameters are transmitted to an automatic tuning engine 12, which generates tuning parameters based on the measurements by the measurement engine 11. The tuning parameters are transmitted to a signal flow engine 13. The signal flow engine 13 generates one or more components of an audio signal flow, where each of the one or more components represents an audio parameter that can be tuned based on the tuning parameters. The output of an audio processing engine 14. The audio processing engine 14 generates a playback audio signal based on one or more components of the signal flow. The output of the audio processing engine 14 can be evaluated by an evaluation engine 15. The evaluation engine 15 enables a user to evaluate the tuning result by "subjective" listening (element 16) or "objective" re-measurement (element 17). Based on the results of subjective listening 16 and / or measurement 17, the user can decide to return to automatic tuning, as indicated by the arrow pointing to the automatic tuning engine 12. Instead of returning to automatic tuning, the user can directly fine-tune through a fine-tuning module 18. The fine-tuning module 18 implements further adjustment of the tuning parameters. Based on the measurement feedback loop, the fine-tuning can also be automated, and / or it can include adjustments that the user can make through the user interface of the system. Based on the fine-tuning result, the user can cycle back to automatic tuning for re-tuning until a satisfactory result is obtained, as indicated by the arrow from the fine-tuning module 18 to the automatic tuning engine 12.

[0025] The elements of a system according to an embodiment of the present disclosure, as shown below, will be described in more detail. Figure 1 as shown

[0026] Measurement

[0027] The measurement engine 11 is capable of performing different types of measurements, such as impulse response measurement, total harmonic distortion (THD) measurement, phase and frequency measurement, signal-to-noise ratio (SNR) measurement, polarity measurement, etc., and feeding the measurement data directly to the auto-tuning engine 12. The measurements can be related to various speaker types and configurations. The measurements can be performed by microphones or microphone arrays of different types and configurations. The user can configure the speaker and / or microphone layout through the user interface of the system.

[0028] Figure 2 An exemplary flowchart showing the steps taken by the measurement engine 11 according to an embodiment of the present disclosure is shown. Figure 3 An exemplary use case related to an automotive audio system with a subwoofer, woofer, midrange speaker, and tweeter is shown, where the measurements are performed using a microphone array on four seats. The speaker configuration is as shown on the left hand side of Figure 3 the figure.

[0029] Auto - tuning

[0030] The system according to an embodiment of the present disclosure includes a user interface to enable the user to define objectives, such as spectral and temporal behavior, sound stage, spatial balance, sense of immersion, and sound depth. The user interface enables the user to configure parameters to achieve the desired objective behavior. The backend algorithm (also referred to as the "solver") processes the objectives and user-defined configurations to obtain filter parameters, gains, and delays as tuning outputs. The solver can have a modular and scalable architecture, enabling it to scale the objectives and configurations for different application scenarios. For example, by adding different use cases and tuning modes, the preferences of various users or customers can be achieved.

[0031] Figure 4 Examples of user-defined requirements and configurations included in the auto-tuning process are worked out. Figure 5 A configuration panel (user interface) of the auto-tuning engine 12 is shown, including speaker architecture, microphone selection, target curve definition, speaker and filter configuration, and graphs of the target curve and measurement response.

[0032] The system according to an embodiment of the present disclosure may include one or more of the following features:

[0033] User-defined target tuning curve: The user can define a target curve in the frequency domain through the user interface of the system. The target curve can represent a preferred listening experience. The measured response of the speaker is tuned to reach or approximate the target curve. For example, the response can be equalized through digital audio filters (such as IIR biquadratic filters or FIR filters), delays, and gains.

[0034] Balance between seats: In an in-vehicle audio system, a microphone array for measurement and tuning can be configured through a user interface. This configuration can include the selection and weighting of microphones, enabling the user to decide which seat to focus on and how much weight to give to each seat in a multi-seat configuration.

[0035] Delay calculation: The auto-tuning engine 12 can include a delay detection scheme using impulse responses. Thus, the speaker with the longest delay can be selected as the reference speaker. Other speakers can be aligned with the reference speaker through a user-defined delay offset.

[0036] Flexible grouping for gain alignment: The auto-tuning engine 12 can be configured to perform gain alignment towards a target curve between speakers, for example, within or between areas in a room or a car. To align areas, speaker groups can be flexibly configured, and relative level offsets can be defined.

[0037] Multiple scalable use cases and tuning modes: For example, to perform balance tuning on left and right speakers, a symmetric use case can be defined to combine left and right paired speaker signals for tuning. Taking a car as an example, the front speakers use the measurement of the microphone array placed on the driver's seat, the rear speakers use the measurement of the microphone array on the rear right seat, and the subwoofer uses both microphone arrays. Asymmetric use cases with different "focus seats" as different tuning modes can also be used. In an asymmetric use case, only the measurement data for one selected seat and one speaker is used for further processing / tuning. For example, the "driver" tuning mode only uses data from microphones arranged on or near the driver's seat. For example, different use cases and the selection of "focus seats" can be input through the user interface of the auto-tuning engine 12.

[0038] Nonlinear multivariable optimizer: The auto-tuning engine 12 can include an optimizer to provide optimized filter parameters, thereby equalizing the measured response with respect to a target curve. The optimizer is constrained by multiple boundaries, such as quality factor, frequency, and gain, to shape the filter so that the tuned measured response reaches the target. The filter parameters can be converted into coefficients for easy deployment in the signal flow.

[0039] Figure 6 and Figure 7 respectively show the responses before and after tuning with respect to a user-defined target curve.

[0040] Signal - flow integration

[0041] In a system according to an embodiment of the present disclosure, the tuning functionality can be embedded into a larger software architecture that includes additional features or technologies. In an embodiment, this is achieved through a signal flow tool that a user can use to implement a more complex signal flow and software architecture in the form of multiple audio objects (gains, delays, complex algorithms, etc.). In the present disclosure, such audio objects are also referred to as audio components. For example, a signal flow can be run on a target processor and tested in real time, for example, in a PC environment. The audio blocks required for tuning, such as equalizer (EQ) blocks, gain blocks, delay blocks, can be created in a signal flow or as part of a signal flow. Figure 8 An example is shown. The signal stream integration engine 13 can be configured to write the tuning results represented by the tuning parameters output by the automatic tuning engine 12 directly into these blocks. The signal stream can then be analyzed in real time, listened to by the user, and / or loaded onto a target processor, such as a head unit or audio amplifier in an automotive application.

[0042] Evaluation / Verification

[0043] The system according to the embodiments of the present disclosure provides an integrated signal flow in which tuning can be applied to an audio playback signal. Depending on the user's preferences, playback can be used to re-measure, objectively evaluate the tuning, or subjectively evaluate the tuning performance, such as by listening. Based on the evaluation, the user can further adjust the tuning parameters according to their specific preferences using the integrated signal flow and audio object control tools (e.g., user interface panels and real-time analyzers), or adjust the configuration back to the automatic tuning engine for re-tuning.

[0044] Manual fine - tuning

[0045] In a system according to an embodiment of the present disclosure, the tuning results can be made fully visible in the signal stream. Based on subjective / objective evaluation, the user can directly access the tuning parameters and can modify them for fine tuning. Figure 9 , Figure 10 and Figure 11 The filter (IIR biquad), delay and gain panels are shown separately, as well as the tuning result, which can be further modified by the user.

[0046] Thus, the system provides an end-to-end tool that includes all aspects required for baseline tuning: measurement, tuning, signal flow integration, and evaluation. It also enables manual fine-tuning based on baseline tuning. Specifically, the system may include or provide the following features and technical advantages:

[0047] ●Measurement

[0048] ○Flexible selection and configuration of speaker types and layouts.

[0049] ○ Synchronous and asynchronous measurement modes for obtaining impulse responses and other signal representations, including direct recording.

[0050] ○ Measurement verification to cross-check SNR, THD, and polarity.

[0051] ● Automatic tuning

[0052] ○ Flexible and scalable configuration to meet different user preferences.

[0053] ○ Balance between different seats.

[0054] ○ Fast and consistent tuning.

[0055] ● Signal flow integration

[0056] ○ Tuning results are directly integrated into the signal flow and can be immediately sent to the processor and speakers.

[0057] ○ The signal flow can be deployed on any hardware.

[0058] ● Verification

[0059] ○ Objective: By integrating tuning parameters into the signal flow, re-measurement can be performed to verify whether the target has been achieved.

[0060] ○ Subjective: Signal flow integration enables real-time listening to music with applied tuning.

[0061] ● Manual fine-tuning

[0062] ○ Tuning parameters are completely transparent, which enables users to perform manual fine-tuning based on the baseline tuning results.

[0063] ● Flexible re-tuning

[0064] ○ Based on subjective and / or objective evaluation, automatic tuning can be re-triggered for re-tuning.

[0065] ○ Based on the fine-tuning results, automatic tuning can be re-triggered for re-tuning.

[0066] The system provides a platform for automatically tuning an audio system, implementing a complete tuning chain including measurement, tuning, signal flow integration, and evaluation. Compared with manual baseline tuning, the system provides faster and more consistent results and is thus more efficient in terms of time and cost. The system achieves more consistent tuning results in different automotive or other environments. In addition, automatic tuning can balance the tuning between multiple seats. The user interface supports flexible and scalable configuration and goals, and users can manipulate and select this configuration and goal. Subjective and objective evaluations are implemented, and the audio can be re-tuned and / or manually fine-tuned according to the user's requirements.

[0067] The system can be applied to various environments, such as vehicles, home theaters, and studios.

Claims

1. An automatic audio tuning system, the system comprising: a measurement engine for obtaining first measurements of one or more parameters associated with audio signals from one or more speakers; an automatic tuning engine for receiving the first measurement and generating tuning parameters based on the first measurement; a signal stream integration engine for receiving the tuning parameters and generating one or more components of a signal stream, wherein each of the one or more components of the signal stream represents an audio parameter that can be tuned based on the tuning parameters; an audio signal processing engine for receiving the one or more components of the signal stream and generating a playback audio signal based on the one or more components of the signal stream; as well as An evaluation engine is used to implement evaluation of the playback audio signal.

2. The system of claim 1, wherein the tuning parameters represent one or more of filter parameters, time parameters, spectral parameters, gain, delay, and EQ parameters.

3. A system according to claim 1 or 2, wherein the evaluation engine is configured to obtain a second measurement based on the playback audio signal, and / or wherein the evaluation engine is configured to enable manual or automatic verification and / or adjustment of the tuning parameters.

4. A system according to any preceding claim, further comprising a user interface configured to enable a user to adjust one or more tuning parameters, wherein the signal flow integration engine is configured to adjust the one or more components of the signal flow based on the user adjusted tuning parameters.

5. The system of claim 4, wherein the tuning parameters include one or more of filter parameters, time parameters, spectral parameters, gain, delay, and EQ parameters.

6. The system of any preceding claim, further comprising a user interface configured to enable a user to define a target curve in the frequency domain, wherein the automatic tuning engine is configured to generate the tuning parameters based on the target curve.

7. A system according to any preceding claim, further comprising a user interface configured to enable a user to define a configuration of one or more seats in a vehicle in which the playback audio signal is to be played back, and / or to associate a weight with each of the seats, wherein the automatic tuning engine is configured to generate the tuning parameters based on the user defined configuration and / or weights.

8. A system according to any preceding claim, wherein the system is configured to determine the distances of the speakers from each other and / or from a reference point by detecting delays in the impulse responses of the speakers, wherein the system further comprises a user interface configured to enable a user to select one of the speakers as a reference and to define delay offsets for the other speakers, wherein the automatic tuning engine is configured to generate the tuning parameters based on the selected speakers and the user defined delay offsets.

9. A system according to any preceding claim, wherein the system comprises a user interface configured to enable a user to group loudspeakers in one or more zones and define relative level offsets, and wherein the automatic tuning engine is configured to perform gain alignment between loudspeakers towards a user defined target curve within one of the zones and / or between the zones.

10. A system according to any preceding claim, wherein the system is capable of operating in a symmetrical mode and / or an asymmetrical mode, wherein in the symmetrical mode the automatic tuning engine is configured to combine measured responses of left and right paired speaker signals relative to a seat of a vehicle from which the playback audio signal is to be played back, and wherein in the asymmetrical mode the automatic tuning engine is configured to process the measurements from a speaker at a position of a selected seat of the vehicle from which the playback audio signal is to be played back, wherein the automatic tuning engine is configured to generate the tuning parameters based on selection of the symmetrical mode or the asymmetrical mode.

11. The system of any preceding claim, wherein the automatic tuning engine generating the tuning parameters comprises generating biquad parameters, delays and gains to equalize a measured response relative to a user defined target curve.

12. A system according to any preceding claim, wherein the measurement engine is configured to measure one or more of the following audio parameters: impulse response, THD, phase, frequency, SNR, polarity, and / or, wherein the measurement engine is operable to perform synchronous and asynchronous measurements of the audio parameters.

13. A system according to any preceding claim, further comprising one or more microphones or microphone arrays to perform the measurements, wherein the microphones and / or the microphone arrays are configurable to perform measurements in relation to different types and / or arrangements of loudspeakers.

14. A system according to any preceding claim, wherein the system is implemented by instructions executable on a computer, and / or wherein the system is implemented in a motor vehicle, and preferably wherein the system is connected to or is part of an in-vehicle audio system.

15. A method for tuning an audio signal, the method comprising: measuring one or more parameters associated with audio signals from one or more speakers; generating tuning parameters based on the measured parameters; generating one or more components of a signal stream, wherein each of the one or more components of the signal stream represents an audio parameter that can be tuned based on the tuning parameter; generating a playback audio signal based on the one or more components of the signal stream; as well as The playback audio signal is evaluated and the tuning parameters are optionally adjusted based on the evaluation.

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