Audio Source Loudness Normalization Without Pumping Artifacts
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Solution Overview
Problem
Existing volume control methods for audio sources, such as radio stations, suffer from manual adjustments causing user distraction and introduce artifacts like 'pumping' and reduced dynamics, which are not suitable for high-end audio systems.
Innovation Solution
A device comprising a loudness analyzer and volume regulator that analyzes audio signals over a time period to determine and store loudness values, allowing for adaptive volume control with a learning phase and adaptation phase, minimizing audible adjustments and maintaining dynamic range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If adaptive volume adjustment is applied during listening, then volume differences between stations are equalized, but artifacts such as pumping and reduced dynamics arise
Solution Approach 1:
The system performs preliminary loudness analysis and stores reference values before actual playback. During playback, it compares current loudness against pre-stored reference values and applies compensation only when deviations exceed a threshold, avoiding continuous adjustment artifacts while maintaining volume consistency.
2Ease of operation
If manual volume readjustment is performed, then volume differences between stations are corrected, but user distraction and safety issues arise
Solution Approach 1:
The system automatically performs loudness measurement, reference value storage, and volume compensation without user intervention. The control unit continuously monitors loudness deviations and applies corrections autonomously, eliminating the need for manual adjustments and associated safety risks.
3Measurement precision
If loudness analysis is performed over a long time period, then accurate loudness values are obtained, but delay in volume normalization occurs when switching sources
Solution Approach 1:
The system performs loudness analysis and stores reference values in advance during idle periods or when sources are not actively playing. When a source is selected, the pre-stored reference values are immediately applied, enabling instant volume normalization without requiring real-time analysis delays.
Solution Approach 2:
The system maintains different reference loudness values for different audio sources individually. When switching between sources, it retrieves the specific pre-stored reference value for the selected source and applies targeted compensation, achieving fast and accurate normalization tailored to each source's characteristics.
4Stability of the object's composition
If continuous loudness adaptation is applied, then volume consistency is maintained, but dynamic range and audio transparency are reduced
Solution Approach 1:
The system applies volume compensation only partially and selectively - only when loudness deviations exceed a predetermined threshold. By avoiding continuous adjustment and acting only when necessary, it maintains volume consistency while preserving audio dynamics and transparency.
Data Source
AI summary
A device for volume control for at least two audio sources includes a loudness analyzer and a volume regulator. The loudness analyzer is configured to analyze an audio signal of the first one and of the second one of the two audio sources over a time period, to determine a first and a second loudness value, respectively, as a function thereof, and to store same while associating them with the first and the second audio source. The volume regulator is configured to adapt the audio signal of the currently selected first and/or second one of the two audio sources in accordance with the corresponding first and/or second loudness value.