Audio System Phase Shifter Virtual Center Speaker

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Solution Overview

Problem

Modern audio systems in vehicles face challenges in providing effective sound localization due to asymmetrical listener positions and the need for a center loudspeaker, which is often aesthetically undesirable and complex to position.

Innovation Solution

An audio system using two loudspeakers with differing phase responses over frequency, and a signal processing unit with a phase shifter to align these responses, creating a virtual center speaker effect without the need for a physical center loudspeaker.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a center loudspeaker is positioned in the central console of a vehicle, then sound localization is improved, but aesthetic appearance deteriorates and space requirements increase

Engineering Contradiction:
Improvesound localizationVSAvoidaesthetic appearance
Core Design Contradiction:
Measurement precisionVSShape

Solution Approach 1:

The patent creates a virtual center loudspeaker through signal processing that replicates the acoustic effect of a physical center speaker without requiring actual hardware installation. The phase shifter unit generates signals that simulate centralized sound emission, providing the localization benefits of a center speaker while maintaining aesthetic vehicle interior design and preserving space

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent replaces the mechanical/physical center loudspeaker with an electronic signal processing system. Instead of using a physical speaker positioned in the center console, the system uses phase shifting and signal manipulation to create the acoustic perception of a centered sound source, thereby eliminating the need for mechanical installation while achieving the same acoustic goal

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If a center loudspeaker is positioned in the central console of a vehicle, then sound localization is improved, but device complexity increases

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

Solution Approach 1:

The patent extracts the essential function of a center loudspeaker (providing centralized sound emission for localization) and separates it from the physical hardware requirement. By taking out the acoustic function from the mechanical implementation, the system achieves sound localization without the complexity of installing and positioning a physical center speaker in the vehicle's central console

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The phase shifter unit and signal processing system serve multiple functions: they create the virtual center speaker effect, maintain compatibility with existing two-channel audio systems, and provide adaptable phase adjustment for different listening positions. This multi-functionality reduces overall system complexity compared to installing dedicated center speaker hardware

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

3Measurement precision

If loudspeakers are positioned for optimized three-dimensional audio signal reproduction, then sound localization is improved, but space requirements and aesthetic appearance deteriorate

Engineering Contradiction:
Improvesound localizationVSAvoidspace requirement
Core Design Contradiction:
Measurement precisionVSArea of stationary object

Solution Approach 1:

The patent creates a virtual acoustic environment that replicates the effect of optimized loudspeaker positioning without requiring physical relocation of speakers. The phase shifter unit generates signals that simulate centralized sound emission, providing the localization benefits of optimally positioned speakers while maintaining existing speaker placements and preserving vehicle interior space

Inventive Principle:
Principle #26Copying

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 solution enhances sound localization by aligning phase responses, ensuring a consistent hearing experience across different seating positions and eliminating the need for a center loudspeaker, thus improving the three-dimensional audio effect.

Implementation Method 1

a phase shifter unit that phase-shifts at least one of the input signals such that the difference in the phase responses is constant over frequency in a frequency band

Methodology Applied
Scientific EffectPhase shifting:

Data Source

PatentEP2190221B1Audio system
Publication Date: 2018.09.12 HARMAN BECKER AUTOMOTIVE SYST GMBH
  • EP2190221B1 patent drawingFigure 1~2
  • EP2190221B1 patent drawingFigure 3~4
  • EP2190221B1 patent drawingFigure 5

AI summary

An audio system is disclosed that enhances the localization of sound perceived by a listener. The system comprises two loudspeakers arranged distant from each other and from the listener, where the sound is transmitted from each of the loudspeakers to the listener according to a respective transfer function and the transfer functions differ at least in their phase responses over frequency. The system further comprises a signal processing unit that is connected upstream of the loudspeakers and that receives two electrical useful signals to be radiated as respective sound signals by the two loudspeakers. The signal processing unit comprises a phase shifter unit that phase-shifts at least one of the input signals such that the difference in the phase responses is constant over frequency in a frequency band.