Speech-Aware Multichannel Gain Control for In-Car Audio Loudness
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Solution Overview
Problem
In noisy environments, such as vehicles, audio signals with varying signal levels and speech components often result in insufficient loudness perception of dialogues, and existing technologies fail to dynamically adjust loudness levels effectively to balance speech clarity with noise reduction and prevent hearing damage.
Innovation Solution
A method and system that dynamically adapt the gain of N-channel audio signals by determining perceived loudness and presence of speech components, using separate gain control units for speech and other audio channels, with different gain parameters to maintain speech clarity and limit signal levels within a predefined range, while considering ambient noise based on vehicle speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the overall audio signal level is increased to exceed vehicle noise, then speech intelligibility improves, but hearing damage risk increases and perception becomes painful
Solution Approach 1:
The patent applies different gain parameters to different audio channels based on their content type. Speech channels receive higher gain adjustment to ensure intelligibility, while music channels receive lower gain adjustment to prevent overall loudness from causing hearing damage. This localized differentiation resolves the contradiction by optimizing each channel's gain independently rather than applying a uniform adjustment.
Solution Approach 2:
The audio signal is segmented into speech channels and music channels, with separate gain control applied to each. The system identifies speech content and applies a first gain parameter to speech channels while applying a second, lower gain parameter to music channels. This segmentation allows the system to prioritize speech intelligibility while controlling overall loudness to prevent hearing damage.
2Manufacturing precision
If different tracks have different signal level ranges, then audio fidelity is maintained, but loudness perception becomes inconsistent across tracks
Solution Approach 1:
The patent implements dynamic gain adjustment that adapts to the content of each track and channel. The gain parameters are not fixed but are dynamically adjusted based on real-time analysis of the audio signal characteristics. This allows the system to maintain the original dynamic range and fidelity of each track while compensating for loudness differences between tracks, ensuring consistent perception without sacrificing audio quality.
3Reliability
If speech channel gain is increased to improve dialogue perception, then speech intelligibility improves, but overall audio balance is disrupted
Solution Approach 1:
The system applies localized gain adjustment specifically to speech channels while maintaining different gain levels for music channels. This selective approach allows speech intelligibility to be improved without proportionally increasing the overall audio level, thereby preserving the balance between different audio elements. The speech channels are enhanced locally without disrupting the global audio composition.
Data Source
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AI summary
The invention relates to a method for adapting a gain of an N channel audio input signal in order to generate an N channel audio output signal, wherein the N channel audio input signal comprises a speech input channel (21), in which speech signal components, if present in the N channel audio input signal, are present, and comprising other audio input channels (20). a perceived loudness of the N channel audio input signal is dynamically determined and it is determined whether speech signal components are present in the speech input channel (21). If this is the case the gain of the speech input channel is adapted differently compared to the gain of the other audio input channels.