Positional Subwoofer Signal Processing for Bass Image Localization

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Solution Overview

Problem

Conventional loudspeakers struggle to adequately localize low-frequency sound components, particularly when the sound image needs to move within an acoustic space, as subwoofers are primarily used for loudness enhancement rather than sound image localization.

Innovation Solution

A signal processing method that assigns sound sources to subwoofers based on their positional relation within an acoustic space, generating sound signals that enhance localization of low-frequency components by utilizing a sound source assigner and signal processor to generate specific sound signals for subwoofers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional loud speakers (main speakers) are used alone for sound image localization, then high-frequency sound localization is achieved, but low-frequency sound image localization is insufficient

Engineering Contradiction:
Improvesound image localization accuracyVSAvoidfrequency range coverage
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent applies multi-functionality by enabling subwoofers to perform both their traditional function of reproducing low-frequency sound components for loudness enhancement and a new function of localizing low-frequency sound images. Through the sound source assigner, subwoofers are assigned specific sound sources based on positional relationships, allowing them to reproduce directed low-frequency sounds that create localized sound images rather than just omnidirectional bass reinforcement.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Power

If subwoofers are used for loudness enhancement, then low-frequency volume is increased, but sound image localization capability is lost

Engineering Contradiction:
Improvelow-frequency loudnessVSAvoidsound image localization accuracy
Core Design Contradiction:
PowerVSMeasurement precision

Solution Approach 1:

The patent applies segmentation by dividing the acoustic space into multiple regions and assigning different sound sources to different subwoofers based on their positional relationships with sound sources. This segmentation allows each subwoofer to reproduce specific directional low-frequency components, enabling the system to maintain both high loudness and precise sound image localization by treating each subwoofer as an independent sound reproduction unit rather than a single omnidirectional bass source.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4676096A1Signal processing method, signal processing device, computer program, and audio system
Publication Date: 2026.01.07 YAMAHA CORP
  • EP4676096A1 patent drawingFigure 1~2
  • EP4676096A1 patent drawingFigure 3~4
  • EP4676096A1 patent drawingFigure 5~6

AI summary

A signal processing method assigning each of a plurality of sound sources that correspond to different positions, to one or more subwoofers installed in an acoustic space, in which each of the plurality of sound sources is assigned based on a positional relation between each of the plurality of sound sources and a plurality of subwoofers installed in the acoustic space and including the one or more subwoofers; and based on results of assignment of each of the plurality of sound sources, generates, from a plurality of sound source signals corresponding to respective ones of the plurality of sound sources, a plurality of first sound signals corresponding to respective ones of the plurality of subwoofers.