Spatial Audio Mixing for Clearer Rear Sound Localization

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Solution Overview

Problem

Humans have a lower perception of sounds arriving from behind compared to those from the front, leading to difficulty in distinguishing and localizing sounds from the rear.

Innovation Solution

A sound reproduction method that involves obtaining audio signals from specific ranges and directions, applying correction processes to enhance the intensity of sounds arriving from behind, and mixing these signals to improve perception.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If sounds are reproduced from speakers arranged around the listener, then spatial sound distribution is improved, but perception level of sounds from behind remains low

Engineering Contradiction:
Improvesound distributionVSAvoidperception level
Core Design Contradiction:
Illumination intensityVSMeasurement precision

Solution Approach 1:

The patent applies local quality by differentiating signal processing based on sound direction. Front sounds are processed with one set of parameters while back sounds receive different processing parameters, specifically enhancing the intensity and clarity of rear sounds to compensate for the listener's reduced perception capability in that direction.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes acoustic parameters (intensity, frequency response, timing) based on the direction of sound arrival. By detecting the direction of incoming sounds and dynamically adjusting reproduction parameters, the system enhances perception of sounds from behind while maintaining natural reproduction of sounds from the front.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If audio signals are enhanced to increase perception of rear sounds, then perception level is improved, but sound localization accuracy may deteriorate

Engineering Contradiction:
Improveperception levelVSAvoidlocalization accuracy
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent employs dynamic signal processing that adapts in real-time based on sound direction. The enhancement parameters are continuously adjusted according to the detected direction of arrival, allowing the system to optimize both perception level and localization accuracy for sounds from different directions rather than using static enhancement.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system uses direction detection feedback to control the enhancement process. By continuously monitoring the direction of incoming sounds and using this information to adjust the reproduction parameters, the system maintains accurate localization while enhancing perception of rear sounds.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4124072B1Sound reproduction method, computer program, and sound reproduction device
Publication Date: 2026.01.07 PANASONIC INTELLECTUAL PROPERTY CORP OF AMERICA
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  • EP4124072B1 patent drawingFigure 2
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AI summary

A sound reproduction method includes: obtaining a first audio signal indicating a first sound which arrives at a listener (L) from a first range (D1) and a second audio signal indicating a second sound which arrives at the listener (L) from a predetermined direction; when the first range (D1) and the predetermined direction are determined to be included in a second range (D2) which is a back range relative to a front range in the direction that the head part of the listener faces, performing a correction process on at least one of the first audio signal or the second audio signal so that intensity of the second audio signal becomes higher than intensity of the first audio signal; and performing mixing of the at least one of the first audio signal or the second audio signal, and outputting, to an output channel, the first and second audio signals.