Binaural Audio Playback With Band-Split Crosstalk Cancellation

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Solution Overview

Problem

Existing sound reproduction systems that achieve binaural independent control require complex digital signal processing, leading to high computational costs.

Innovation Solution

A sound reproduction system that uses a combination of polarity inversion and simple delay techniques to cancel crosstalk, assigning specific frequency bands to speakers and applying relative delay times to reduce computational complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an inverse system is constructed and controlled strictly for all frequencies using digital signal processing, then crosstalk cancellation is achieved, but computational cost increases

Engineering Contradiction:
Improvecrosstalk cancellationVSAvoidcomputational cost
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The frequency spectrum is divided into multiple discrete frequency bands, with each band assigned to specific speakers. This segmentation allows the system to process only relevant frequency ranges for each speaker rather than computing inverse systems for all frequencies across all speakers, significantly reducing computational complexity while maintaining effective crosstalk cancellation in each frequency band.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system changes the approach from computing inverse systems across the entire frequency spectrum to using simple delay parameters and polarity inversion for specific frequency bands. This parameter change transforms a computationally intensive operation into a simple time-shift and phase-inversion operation, dramatically reducing computational cost while preserving the essential crosstalk cancellation function.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If detailed design through digital signal processing is used to control the inverse system, then binaural independent control is achieved, but the processing complexity increases

Engineering Contradiction:
Improvebinaural independent controlVSAvoidprocessing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

Instead of computing complex inverse systems through detailed digital signal processing, the system uses polarity inversion (multiplying by -1) combined with simple time delays. This inverted approach achieves the same phase correction effect with much simpler operations, reducing processing complexity while maintaining binaural independent control accuracy.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The system pre-determines the delay times and polarity inversions for each speaker based on the frequency band assignment and speaker positions. These preliminary settings eliminate the need for real-time complex digital signal processing during playback, as the phase corrections are predetermined and applied through simple delay and inversion operations.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If filters are constructed for each speaker to cancel crosstalk across all frequencies, then sound directionality is improved, but the system complexity increases

Engineering Contradiction:
Improvesound directionalityVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system segments the frequency spectrum and assigns specific frequency bands to specific speakers, eliminating the need for complex all-frequency filters for each speaker. Each speaker only needs to handle its assigned frequency band with simple delay and polarity inversion, greatly reducing system complexity while maintaining sound directionality through proper frequency-band-specific phase control.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4622302A1Audio playback system
Publication Date: 2025.09.24 KAJIMA CORP
  • EP4622302A1 patent drawingFigure 1
  • EP4622302A1 patent drawingFigure 2
  • EP4622302A1 patent drawingFigure 3

AI summary

A sound reproduction system includes a controller configured to reproduce three channels of sound from a plurality of speakers. The controller has an inversion unit configured to invert the polarity of either one of (i) an input signal for left speakers based on a left recording signal or (ii) an input signal for right speakers based on the left recording signal, and to invert the polarity of either one of (i) an input signal for right speakers based on a right recording signal or (ii) an input signal for left speakers based on the right recording signal, and a splitting unit configured to split the left recording signal and the right recording signal so as to form signals having discrete bandwidths. Either the plurality of speakers or the controller includes delay means for delaying, by a predetermined delay time for each speaker, the sound corresponding to the signals having the discrete bandwidths output from each left speaker and each right speaker. The delay time is set in advance for each left speaker and each right speaker so that crosstalk is canceled at a predetermined frequency.