Sum-Difference Speaker Arrays for Low-Interference Stereo Playback
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Solution Overview
Problem
Existing audio playback systems face issues with creating additional input channels using static upmixers, leading to undesirable audio artifacts and interference patterns due to high correlation between left and right input channels.
Innovation Solution
Generate a sum and difference input signal from the left and right channels, applying distinct array transfer functions to these signals, and distribute them across multiple channels for playback, reducing correlation and interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If static upmixers are used to create additional input channels, then the number of playback channels can be increased, but undesirable audio artifacts and interference patterns occur due to high correlation between left and right input channels
Solution Approach 1:
The patent transforms the input signal representation from correlated left-right channels to uncorrelated sum-difference channels. This parameter transformation in the signal domain eliminates the high correlation issue, allowing multiple playback channels to be created without generating audio artifacts and interference patterns.
2Reliability
If left and right input channels are highly correlated, then stereo compatibility is maintained, but creating additional channels results in interference patterns
Solution Approach 1:
The patent applies a linear transformation to convert correlated left-right stereo signals into sum and difference components. This parameter change creates uncorrelated input signals for the array transfer function processing, eliminating interference patterns while preserving the original stereo information through the reversible transformation.
3Manufacturing precision
If array transfer functions are applied to uncorrelated sum and difference input signals, then psychoacoustic performance is improved, but processing complexity increases
Solution Approach 1:
The patent transforms the audio signal into sum and difference domains before applying array transfer functions. This parameter transformation simplifies the processing by creating uncorrelated inputs, which reduces computational complexity compared to processing highly correlated left-right channels directly, while achieving superior psychoacoustic performance.
Data Source
AI summary
In some embodiments, a method comprises receiving audio content comprising left input channel signals and right input channel signals, and generating first and second input signals from the left and right input channel signals. The first input signal is based on a sum of the left and right input channel signals, and the second input signal is based on a difference of the left and right input channel signals. An array transfer function is applied to the first and second input signals to produce audio output signals, which can be provided to a plurality of audio transducers on one or more playback devices.