Simultaneous MLS and Audio Signal Output for Cabin Impulse Response
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Solution Overview
Problem
Current methods for determining the spatial impulse response of a motor vehicle passenger cell interfere with ambient audio signals, disrupting listening experience and requiring interruption of audio output for measurement.
Innovation Solution
Simultaneously outputting a maximum length sequence (MLS) signal and an audio signal at a lower energy level, creating a combination signal that allows for the determination of room impulse response without interrupting the audio experience, using psychoacoustic masking and energy differences to minimize interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an MLS signal is output alone for determining room impulse response, then measurement precision is improved, but listener comfort deteriorates due to interruption of audio playback
Solution Approach 1:
The patent combines the MLS signal and audio signal into a single combined output signal that is played back through the audio system. This allows the measurement signal to be integrated with the entertainment signal, enabling room impulse response determination without interrupting audio playback and maintaining listener comfort.
Solution Approach 2:
The patent introduces a processing unit that acts as an intermediary between the MLS signal generator and the audio output system. This processing unit combines the MLS signal with the audio signal in a controlled manner, allowing precise extraction of the room impulse response while maintaining the audio experience for the listener.
2Ease of operation
If an MLS signal is output simultaneously with an audio signal, then listener comfort is improved by avoiding interruption, but measurement precision deteriorates due to interference from the audio signal
Solution Approach 1:
The patent extracts the MLS signal component from the combined signal containing both MLS and audio signals. By separating and analyzing only the MLS signal portion, the system can determine the room impulse response with high precision while the audio signal continues to play for listener comfort.
Solution Approach 2:
The patent uses the known characteristics of the original MLS signal to identify and extract its component from the combined output signal. By comparing the recorded combined signal with the original MLS signal pattern, the system can accurately isolate and analyze the MLS portion for measurement purposes.
3Measurement precision
If the MLS signal energy is increased to improve signal quality, then measurement precision is improved, but harmful factors increase due to audible interference and masking of the audio signal
Solution Approach 1:
The patent optimizes the energy level parameter of the MLS signal to achieve the highest possible signal-to-noise ratio for accurate room impulse response determination while keeping the MLS signal energy below the threshold of human auditory perception. This allows high-quality measurements without audible interference.
Solution Approach 2:
The patent utilizes the masking effect of the audio signal, which would normally be considered harmful interference, to actually hide the low-level MLS signal from listener perception. The audio signal serves as a mask that conceals the measurement signal, allowing simultaneous playback without audible interference while maintaining measurement quality.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables accurate determination of room impulse response during ongoing audio playback, improving listener comfort and reducing the disturbing influence of ambient noise, while maintaining the quality of the acoustic measurement.
Implementation Method 1
The MLS signal is preferably output with lower energy, and in particular lower volume, compared to the audio signal. The MLS signal is thus preferably output in an energy and/or volume range where it is inaudible or barely audible to the human ear, especially when output in isolation without the audio signal.
Data Source
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AI summary
Method for determining the spatial impulse response (RIR) of an interior space (3) having a specific spatial volume (2), in particular an enclosed space, comprising the following steps: - simultaneous output of at least one maximum-length sequence signal (MLS signal) (5) and at least one audio signal (6) different from the MLS signal (5) into a spatial volume (2) of an interior space (3) whose spatial impulse response (RIR) is to be determined, wherein a combination signal (7) containing the at least one MLS signal (5) and the at least one audio signal (6) is generated by the simultaneous output of the at least one MLS signal (5) and the at least one audio signal (6), - determining the spatial impulse response (RIR) of the interior space (3) from the combination signal (7).