Inverse Filtering Sound Zone Separation
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Solution Overview
Problem
Existing sound zone reproduction systems face challenges in effectively separating sound fields in reverberant environments without causing annoyance from adjacent sound fields, particularly in implementing a practical system that adapts to user location and reproduces desired sound programs in spatial regions.
Innovation Solution
A sound system utilizing inverse filtering with a filter matrix to process electrical audio signals, where only the minimum phase part of the room transfer matrix is inverted and combined with regularization, to compensate for room transfer matrices and minimize interference between sound zones, ensuring each sound signal corresponds to its intended zone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If inverse filtering is applied to compensate for room transfer matrix, then sound zone separation is improved, but acoustic artifacts and interference increase
Solution Approach 1:
The patent modifies the inverse filtering approach by inverting only the minimum phase part of the room transfer matrix determinant rather than the complete transfer matrix. This parameter change in the filtering strategy reduces acoustic artifacts while maintaining sound zone separation effectiveness.
Solution Approach 2:
Instead of applying complete inverse filtering to the entire room transfer matrix, the patent applies partial action by selectively inverting only the minimum phase component of the determinant. This partial approach achieves sufficient compensation without introducing the full spectrum of artifacts that complete inversion would create.
2Measurement precision
If complete inverse filtering is used, then cross-talk damping is improved, but system complexity and computation increase
Solution Approach 1:
The patent extracts and isolates only the minimum phase component from the complete room transfer matrix determinant for inversion. This extraction approach achieves cross-talk damping by addressing only the essential minimum phase characteristics, thereby reducing system and computational complexity compared to inverting the entire matrix.
3Stability of the object's composition
If regularization is combined with minimum phase inversion, then stability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies regularization as a cushioning measure to the minimum phase inversion process. This beforehand cushioning stabilizes the filtering operation by preventing numerical instabilities and extreme gain variations, making the system more robust to implementation variations.
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 achieves significant cross-talk damping and reduces acoustic artifacts, allowing for effective reproduction of distinct sound zones without substantial interference, thereby enhancing user experience by maintaining desired sound programs in their designated spatial regions.
Implementation Method 1
each configured to convert the processed electrical audio signals into corresponding acoustic audio signals
Implementation Method 2
Each of the acoustic audio signals is transferred according to a room transfer matrix from each of the loudspeakers to each of the sound zones
Implementation Method 3
Inverse filtering is configured to compensate for the room transfer matrix so that each one of the reception sound signals corresponds to one of the electrical audio signals
Data Source
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AI summary
A system and method for acoustically reproducing at least two electrical audio signals and establishing at least two sound zones that are represented by individual patterns of reception sound signals includes processing the at least two electrical audio signals to provide processed electrical audio signals; converting the processed electrical audio signals into corresponding acoustic audio signals with at least two loudspeakers that are arranged at positions separate from each other; transferring each of the acoustic audio signals according to a transfer matrix from each of the loudspeakers to each of the sound zones where they contribute to the reception sound signals; and processing of the at least two electrical audio signals comprises inverse filtering according to a filter matrix. Inverse filtering is configured to compensate for the room transfer matrix so that each one of the reception sound signals corresponds to one of the electrical audio signals.