Three-Emitter Binaural Audio Layout for Crosstalk Cancellation
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Solution Overview
Problem
Conventional binaural sound reproduction systems using two loudspeakers face issues with dynamic range loss and sensitivity to errors due to system inversion, leading to poor control performance and audible distortion, especially at frequencies where the condition number of the plant matrix is high.
Innovation Solution
The implementation of a three-channel sound reproduction system with transducers positioned in different azimuthal regions, where the first transducer is intermediate to the left and right channels, and these channels are designed to transmit predominantly higher frequencies closer to and lower frequencies away from the first transducer, utilizing variable frequency-span transducers to balance singular values and reduce dynamic range loss and error sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If system inversion is used to achieve cross-talk cancellation in binaural reproduction, then spatial accuracy is improved, but dynamic range is lost and error sensitivity increases
Solution Approach 1:
The patent changes the fundamental parameter of transducer configuration from a fixed two-loudspeaker arrangement to a variable three-transducer system where transducer positions and frequency spans are adjusted as parameters. This allows optimization of the transfer function matrix conditioning, reducing error sensitivity while maintaining spatial accuracy through parameter optimization rather than pure mathematical inversion.
Solution Approach 2:
The patent introduces an intermediate processing stage between the audio signal and the transducers, implementing a regularized pseudo-inverse filter design that acts as a mediator. This intermediary filter reduces the amplification of errors and noise that would otherwise occur with direct system inversion, thereby reducing error sensitivity while preserving spatial reproduction accuracy.
2Device complexity
If conventional two-loudspeaker binaural systems are used, then system simplicity is maintained, but control performance deteriorates and distortion increases
Solution Approach 1:
The patent transitions from a two-dimensional loudspeaker arrangement to a three-dimensional transducer configuration, adding spatial dimensionality to the system. By positioning three transducers in specific three-dimensional arrangements rather than simply placing two loudspeakers, the system achieves better control over the sound field while maintaining reasonable complexity through geometric optimization.
Solution Approach 2:
The patent segments the frequency spectrum across multiple transducers, with each transducer handling specific frequency ranges. This segmentation allows each transducer to operate in its optimal frequency band, improving control performance and reducing distortion while distributing the system's functional complexity across multiple specialized components rather than overloading a single two-loudspeaker system.
3Measurement precision
If inverse filters are designed to cancel cross-talk, then spatial separation is improved, but amplification requirements increase causing dynamic range loss
Solution Approach 1:
The patent implements dynamic frequency span allocation where the frequency ranges handled by each transducer are not fixed but can be adjusted dynamically. This dynamic segmentation allows the system to achieve cross-talk cancellation with more balanced energy distribution across transducers, reducing the peak amplification requirements and preserving dynamic range while maintaining spatial separation.
Solution Approach 2:
The patent optimizes parameters of the transfer function matrix through careful selection of transducer positions and frequency spans, changing these physical parameters to improve the conditioning of the system matrix. This parameter optimization reduces the condition number, thereby reducing the amplification factor needed for cross-talk cancellation and preserving dynamic range while achieving spatial separation.
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 maintains a stable signal-to-noise ratio and reduces distortion, providing robust control over sound reproduction across frequencies and locations, while being less sensitive to errors and reflections, thus enhancing the auditory experience.
Implementation Method 1
the second and third sound emitter means being such that predominantly higher frequencies are transmitted closer to the first sound emitter means and predominantly lower frequencies are transmitted away from the first sound emitter means
Data Source
AI summary
A sound reproduction system includes an electro-acoustic transducer and a transducer driver for driving the electro-acoustic transducer. The transducer drive includes a filter which is configured to reproduce at a listener's location an approximation to the local sound field that would be present at the listener's ears in recording space, taking into account the characteristics and intended position of the electro-acoustic transducer relative to the listener's ears. The electro-acoustic transducer includes a first sound emitter which provides an intermediate sound emission channel, and second and third sound emitters providing respective left and right sound emission channels. The first sound emitter is located intermediate of second and third sound emitters. Higher frequencies from at least one of the second and third sound emitters are transmitted closer to the first sound emitter while lower frequencies are transmitted away from the first sound emitter.