Audio Gain Adaptation for Consistent Perceived Loudness
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Solution Overview
Problem
Audio systems struggle to maintain consistent sound levels when playing audio signals from different tracks with varying signal level ranges, leading to unpleasant loudness variations that can be masked by vehicle noise, potentially causing hearing discomfort.
Innovation Solution
A system and method that dynamically adapts the gain of audio signals using psychoacoustic models to generate loudness adaptation indicators, ensuring an average loudness level is maintained across different tracks, incorporating a loudness determination unit, loudness adaptation unit, and gain determination unit to adjust the audio signal gain based on perceived and predetermined loudness levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If audio signals from different tracks with varying signal level ranges are played out, then the audio system can provide diverse music and speech content, but the loudness level varies between tracks making it difficult for users to perceive consistent sound levels
Solution Approach 1:
The system dynamically adjusts the gain for each track based on its perceived loudness level. The gain adaptation is calculated in real-time using psychoacoustic models to match the loudness of the current track with the average loudness level, ensuring consistent perception across diverse audio content while maintaining adaptability to different tracks.
Solution Approach 2:
The system changes the gain parameter of audio signals based on psychoacoustic loudness measurements. By calculating the perceived loudness level of each track and comparing it to the average, the system automatically adjusts the gain parameter to achieve uniform loudness perception across tracks with originally varying signal levels.
2Reliability
If the overall audio level is increased to exceed vehicle noise, then audio signals become perceivable to users, but the loudness may exceed levels that cause hearing damage or pain
Solution Approach 1:
The system uses feedback from psychoacoustic loudness measurements to automatically control the gain. By continuously monitoring the perceived loudness level and comparing it to reference values, the system adjusts the audio output to maintain perceptibility above vehicle noise while preventing excessive loudness that could cause hearing damage.
Solution Approach 2:
The audio system performs self-regulation by automatically calculating and applying gain adaptation based on the inherent loudness characteristics of each track. The system serves itself by using its own audio signal to determine the appropriate gain level, eliminating the need for manual volume adjustment and ensuring safe listening levels.
3Ease of operation
If manual volume adjustment is used to compensate for loudness variations, then users can control audio levels, but this requires continuous user intervention and does not automatically adapt to different tracks
Solution Approach 1:
The system automatically performs loudness normalization without requiring user intervention. It calculates the perceived loudness of each track using psychoacoustic models, determines the appropriate gain adaptation, and applies it automatically, making the audio system self-regulating and eliminating the need for manual volume adjustments.
Solution Approach 2:
The system implements automatic feedback control by measuring the loudness characteristics of each track and using this information to adjust the gain. This closed-loop approach continuously adapts the audio output to maintain consistent perceived loudness across different tracks without user involvement.
Data Source
AI summary
Systems and method for adapting a gain of an audio signal containing at least two different tracks with different signal level ranges. An example system includes a loudness determination unit for determining a perceived loudness of the audio input signal based on a psychoacoustic model of a human hearing. The system further includes a loudness adaptation unit configured to determine a loudness adaptation indicator based on the perceived loudness and a predetermined loudness, and to introduce the loudness adaptation indicator into the audio signal to generate an adapted gain signal. A gain determination unit is configured to adapt the gain for outputting the audio signal containing the at least two tracks based on the loudness adaptation indicators in the adapted gain signal at about the predetermined loudness.