Multizone Audio Rendering Using Orthogonal Basis Functions
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing audio rendering systems fail to precisely control sound leakage between zones and provide a good sense of localization in designated bright zones while maintaining acoustical brightness contrast between bright and quiet zones, especially in extended open spaces.
Innovation Solution
The system models the desired multizone soundfield as an orthogonal expansion of basis functions over the reproduction region using the Gram Schmidt process or Householder transformation, allowing for a weighted least squares solution that optimizes loudspeaker configurations to reproduce the soundfield with reduced computational effort and fewer loudspeakers, enabling precise control of bright and quiet zones within the designated reproduction region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional audio rendering methods are used to reproduce soundfields in multizones, then the system can provide basic sound distribution, but it fails to precisely control sound leakage between zones and provide good localization sense in bright zones
Solution Approach 1:
The reproduction region is divided into multiple zones (bright zones and quiet zones) with distinct acoustic characteristics. Each zone is independently controlled through separate weighting functions in the least-squares optimization, allowing precise sound field reproduction in bright zones while suppressing sound leakage to quiet zones. This segmentation enables the system to achieve good localization sense in bright zones without excessive complexity.
Solution Approach 2:
The system changes the acoustic parameters by introducing zone-dependent weighting functions that modify the least-squares optimization criteria. By adjusting the weights assigned to different spatial regions, the system can precisely control sound pressure levels and acoustic energy distribution in each zone, achieving both high reproduction precision and effective sound leakage control.
2Manufacturing precision
If more loudspeakers are deployed to improve sound field reproduction accuracy, then the reproduction quality increases, but the number of required loudspeakers and computational effort increases
Solution Approach 1:
The system optimizes the weighting parameters in the least-squares formulation to achieve accurate sound field reproduction with fewer loudspeakers. By carefully selecting the weighting functions that emphasize bright zone accuracy while tolerating some error in quiet zones, the system reduces the number of required loudspeakers while maintaining high reproduction accuracy where it matters most.
Solution Approach 2:
The system applies different quality requirements to different spatial regions through zone-specific weighting functions. Bright zones receive high weighting for accurate sound field reproduction, while quiet zones receive lower weighting. This local quality approach allows the system to achieve high reproduction accuracy in critical areas with a reduced number of loudspeakers.
3Reliability
If the system attempts to control acoustic energy in both bright and quiet zones simultaneously, then zone independence improves, but the acoustical brightness contrast between zones decreases
Solution Approach 1:
The system uses parameter changes by introducing asymmetric weighting functions that assign different importance levels to bright and quiet zones. The weighting function includes a parameter that controls the trade-off between zone independence and brightness contrast. By optimizing this parameter, the system maintains good zone control independence while preserving high acoustical brightness contrast through weighted least-squares optimization.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for improved reproduction of the desired soundfield within the designated region, reducing the number of required loudspeakers, enhancing localization, and achieving significant acoustical brightness contrast, with the ability to flexibly locate zones and minimize quiet zone energy density.
Implementation Method 1
sound waves cancel each other out in one area and become amplified in another
Implementation Method 2
modeling a desired multizone soundfield as an orthogonal expansion of basis functions over the desired reproduction region, wherein the orthogonality implies that the inner product of any two basis fuctions in the set over the desired reproduction region is 0, results in the Helmholtz solution
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to an audio rendering system (100), comprising: a plurality of loudspeakers (102) arranged to approximate a desired spatial sound field within a predetermined reproduction region (130), wherein the loudspeakers (102) are configured to approximate the sound field based on a weighted series of orthonormal basis functions for the reproduction region (130).