Bass Management for Object-Based Audio Zones
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Solution Overview
Problem
Traditional bass management systems in audio reproduction face challenges with bass buildup and uneven spectral balance, especially in audio object-based systems with multiple speaker zones, leading to undesirable bass overemphasis and inconsistent sound quality.
Innovation Solution
A method and system that calculate a power-preserving subwoofer contribution coefficient by combining gain coefficients from relevant speakers, ensuring only bass relevant to each zone is directed to its subwoofer, maintaining balanced bass reproduction across different speaker configurations and zones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional bass management sums bass signals from all speakers, then bass reproduction is provided, but bass buildup and overemphasis occur
Solution Approach 1:
The patent segments the bass management process by zone, creating separate bass management paths for different spatial zones (e.g., front zone, rear zone, left zone, right zone). Each zone has its own subwoofer contribution coefficient calculated independently based on the speakers within that zone. This segmentation prevents global bass buildup by limiting bass summation to only relevant local zones rather than summing bass from all speakers system-wide.
Solution Approach 2:
The patent applies local quality by calculating zone-specific subwoofer contribution coefficients rather than using a single global coefficient. Each zone's bass management is optimized independently based on its specific speaker configuration and acoustic characteristics. This allows different parts of the playback environment to have tailored bass reproduction, preventing overemphasis in any single zone while maintaining appropriate bass levels locally.
2Power
If bass signals are summed from multiple speakers, then subwoofer input is provided, but uneven spectral balance occurs
Solution Approach 1:
The patent implements dynamic bass management by calculating subwoofer contribution coefficients that adapt to the specific speaker configuration and zone geometry. Rather than using fixed gain values, the system dynamically determines the appropriate bass signal level for each zone based on the number and positions of speakers contributing bass to that zone. This dynamic adjustment maintains stable spectral balance across different playback configurations and zones.
Solution Approach 2:
The patent changes the parameter of bass signal level control from fixed global gain to dynamic zone-specific coefficients. The subwoofer contribution coefficient is calculated based on zone-specific parameters including speaker positions, zone boundaries, and acoustic characteristics. This parameter change allows the system to maintain consistent spectral balance across varying speaker configurations and playback environments.
3Reliability
If main speakers reproduce full-range audio, then complete sound is provided, but main speakers must be larger
Solution Approach 1:
The patent extracts the bass frequency content from the main speaker signals and redirects it to subwoofers through zone-specific bass management. By taking out the bass portion (typically below 80-120 Hz) from the main speaker signal path and processing it separately through low-pass filtering and zone-based coefficient application, the system allows main speakers to be smaller while maintaining complete full-range sound reproduction through the combination of main speakers and subwoofers.
Data Source
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AI summary
A bass management system and method for mitigating bass management errors by using explicit information available in the object audio rendering process and deriving the correct subwoofer contribution for each audio object. Embodiments of the bass management system and method are used to maintain the correct balance of the bass reproduced by the subwoofer relative to the sound coming out of the other speakers. The system and method are useful for a variety of different speaker configurations, including speaker configurations having different speaker sub-zones. Power-normalized gain coefficients for each speaker are combined and the power of the combined gain coefficients is computed and used to obtain a power- preserving subwoofer contribution coefficient. This subwoofer contribution coefficient is applied to the bass portion of the audio signal and audio objects to determine the contribution of a particular subwoofer.