Vehicle Loudspeaker Array Beamforming for Channel Separation

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Solution Overview

Problem

Existing vehicle loudspeaker systems face challenges in providing high-quality surround sound with good channel separation due to interference from vehicle noises and simultaneous audio consumption, and previous solutions like personalized sound zones using loudspeakers or ultrasonic technology suffer from sensitivity to head movements, health risks, and energy inefficiency.

Innovation Solution

A loudspeaker system with a centrally arranged array of electroacoustic sound converters, supplemented by additional structure-borne sound converters and signal processing for beamforming, which creates separate sound cones for each listening position and uses varying transducer densities for focused radiation, improving channel separation and sound quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If loudspeakers are integrated into headrests for personalized sound zones, then acoustic separation from neighboring zones is improved, but susceptibility to interference from head movements increases

Engineering Contradiction:
Improveacoustic separationVSAvoidstability against head movements
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent transitions from close-proximity loudspeakers (0-dimensional point sources near ears) to distributed loudspeaker arrays across the vehicle interior (2-dimensional spatial distribution). This dimensional change enables beamforming that creates stable sound zones independent of listener position, resolving the contradiction between acoustic separation and stability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent divides the vehicle interior into multiple independent sound zones using distributed loudspeaker segments throughout the vehicle. Each zone can be controlled independently through beamforming, providing both acoustic separation and positional stability without requiring loudspeakers to be physically close to each listening position.

Inventive Principle:
Principle #1Segmentation

2Object-affected harmful factors

If ultrasound technology is used for personalized sound zones, then acoustic separation is improved, but energy efficiency deteriorates

Engineering Contradiction:
Improveacoustic separationVSAvoidenergy efficiency
Core Design Contradiction:
Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The patent changes the frequency parameter from ultrasonic ranges to audible frequency ranges, eliminating the need for high-power ultrasound generation while achieving comparable or superior acoustic separation through beamforming with distributed loudspeaker arrays operating at efficient audible frequencies.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical ultrasound generation system (requiring high power output) with an electromagnetic beamforming system using distributed loudspeakers. This substitution achieves the same acoustic separation function with significantly lower energy consumption by utilizing phase and amplitude control rather than high-power mechanical vibration.

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

3Reliability

If beamforming with distributed loudspeakers is used, then stability against head movements is improved, but channel separation is reduced due to room acoustics

Engineering Contradiction:
ImprovestabilityVSAvoidchannel separation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful effect of room reflections and modes into beneficial elements by using them as part of the sound field control. The distributed loudspeaker array and beamforming algorithms are designed to work with the vehicle's room acoustics rather than against them, using reflections to enhance and stabilize the sound zones while maintaining channel separation through spatial distribution.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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

The system achieves high-quality surround sound with effective channel separation by positioning loudspeakers centrally and using additional structure-borne sound converters to enhance audio fidelity and reduce interference, while maintaining energy efficiency and safety.

Implementation Method 1

A loudspeaker system with a centrally arranged array of electroacoustic sound converters

Methodology Applied
Scientific EffectElectroacoustic transduction:

Implementation Method 2

signal processing for beamforming, which creates separate sound cones for each listening position

Methodology Applied
Scientific EffectBeamforming:

Implementation Method 3

a user-specific audio signal can be reproduced via the plurality of electroacoustic transducers

Methodology Applied
Scientific EffectAcoustic wave propagation: Sound

Data Source

PatentEP3152925B1Loudspeaker system
Publication Date: 2019.07.10 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP3152925B1 patent drawingFigure 1A
  • EP3152925B1 patent drawingFigure 1B
  • EP3152925B1 patent drawingFigure 1C

AI summary

The invention relates to a loud-speaker system for a vehicle, comprising a loud-speaker array which comprises a plurality of electro acoustic transducers which can be controlled individually such that a user-specific audio signal can be reproduced by means of a plurality of electro acoustic transducers for different users in different listening areas in the inside of the vehicle. Said loud-speaker array or an acoustic outlet of the loud-speaker array is arranged in particular, between at least two of the listening positions in the inside of the vehicle, for example, between the driver and the front passenger seat.