Speaker Audio Compensation for Consistent Loudness Across Volumes
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Solution Overview
Problem
Existing audio compensation methods focus on hearing thresholds and are not effective when audio is played at volumes different from the threshold, failing to maintain the intended sound perception across varying playback sound pressure levels.
Innovation Solution
A method for real-time audio processing in audio speaker arrangements that determines playback sound pressure levels and generates compensation filters based on amplitude compensation data, preserving total audio power and ensuring consistent sound perception regardless of playback volume, using pre-stored acoustic transfer data and equal loudness contours.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If audio compensation is based on hearing threshold only, then hearing threshold perception is improved, but sound perception consistency across different playback volumes deteriorates
Solution Approach 1:
The patent applies parameter changes by using equal loudness contours (Fletcher-Munson curves) that define frequency-dependent amplitude adjustments for different playback sound pressure levels. The compensation filter dynamically changes amplitude parameters across frequency bands based on the detected playback volume, transforming the audio signal to maintain consistent perceived loudness across varying playback levels.
Solution Approach 2:
The system implements dynamics by continuously monitoring playback sound pressure level and dynamically adjusting the compensation filter parameters in real-time. The audio processing adapts to changing playback conditions, modifying frequency response characteristics dynamically rather than using fixed compensation, thereby maintaining consistent sound perception across different volume levels.
2Ease of operation
If playback volume is changed, then volume adjustment is achieved, but sound perception consistency deteriorates
Solution Approach 1:
The patent implements feedback by detecting the actual playback sound pressure level from the audio output and using this information to adjust the compensation filter parameters. The system continuously monitors the playback condition and feeds this information back to the audio processing chain, enabling automatic adaptation to maintain consistent sound perception regardless of volume changes.
Solution Approach 2:
When playback volume changes, the system changes the compensation parameters based on equal loudness contours corresponding to the new sound pressure level. This transforms the audio signal's frequency spectrum to compensate for the changed listening conditions, ensuring that the perceived sound remains consistent despite volume adjustments.
3Manufacturing precision
If compensation filter is applied, then frequency balance is improved, but total audio power may be altered
Solution Approach 1:
The patent applies local quality by implementing frequency-dependent amplitude compensation rather than uniform gain adjustment. Different frequency bands receive different amplitude adjustments based on the equal loudness contours, with bass and treble frequencies receiving different treatment than mid-range frequencies. This localized approach corrects frequency balance while the overall power is managed separately to preserve total audio energy.
Data Source
AI summary
Presented is a method (100) for real-time processing an audio stream in an audio speaker arrangement comprising at least one audio speaker. The method (100) comprises receiving (110) an audio-stream and a playback volume associated with the audio-stream and determining (120) a playback sound pressure level of the audio speaker based on the playback volume and pre-stored acoustic transfer data. The pre-stored acoustic transfer data is associating the playback volume with the playback sound pressure level of the audio speaker. The method further comprises generating (130) a compensation filter based on amplitude compensation data associated with the determined playback sound pressure level and filtering (140) the audio-stream using the compensation filter and applying a gain factor to the audio stream generating a compensated audio-stream. The gain factor is configured such that a total audio power of the audio stream is preserved regardless of the compensation filter. The compensated audio stream is provided (150) to the audio speaker (21). Additionally, an audio speaker arrangement and a computer program product are presented.