Room Communication System Stabilizing Feedback via Time Delay

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Solution Overview

Problem

Existing passenger compartment communication systems in vehicles face challenges with acoustic feedback, unstable signal processing, and mismatch between acoustic and visual localization of the speaker, leading to poor speech comprehensibility and discomfort for passengers.

Innovation Solution

Combining active noise compensation with psycho-acoustic effects of spatial hearing to stabilize electro-acoustic feedback loops, reduce artifacts, and improve the matching between acoustic and visual localization of the speaker, using delayed signal processing and additional loudspeakers to create an anti-noise field and amplify desired sound signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If multiple loudspeakers and microphones are used to improve speech comprehensibility, then speech intelligibility is improved, but acoustic feedback and system instability increase

Engineering Contradiction:

Improvespeech comprehensibilityVSAvoidsystem stability

Core Design Contradiction:

Loss of informationVSReliability

Solution Approach 1:

The patent implements feedback mechanisms through acoustic feedback compensation using adaptive filters and feedback suppression algorithms. The system continuously monitors acoustic feedback loops and applies corrective signal processing to stabilize the system while maintaining speech intelligibility improvements from the multi-loudspeaker/microphone configuration.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent converts harmful acoustic feedback into beneficial effects by using feedback suppression techniques and acoustic feedback compensation. The adaptive filters process the feedback signals to cancel unwanted feedback loops while preserving the beneficial acoustic enhancement from the distributed loudspeaker-microphone system.

Inventive Principle:

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

2Loss of information

If loudspeakers are positioned in the immediate vicinity of listeners to improve speech reproduction, then speech intelligibility is improved, but acoustic localization and visual localization mismatch increases

Engineering Contradiction:

Improvespeech intelligibilityVSAvoidlocalization accuracy

Core Design Contradiction:

Loss of informationVSMeasurement precision

Solution Approach 1:

The patent addresses localization mismatch by utilizing temporal dimension through precise time delay control. By adjusting the timing of audio signals relative to visual speaker positions, the system creates acoustic localization that matches visual localization, resolving the spatial mismatch while maintaining intelligibility benefits from proximal loudspeaker placement.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Reliability

If signal processing is applied to reduce feedback, then system stability is improved, but processing complexity and artifacts increase

Engineering Contradiction:

Improvesystem stabilityVSAvoidsignal processing complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies partial feedback suppression rather than complete elimination. The adaptive filters process only the most significant feedback components, achieving sufficient stability improvement without over-processing. This selective approach reduces computational complexity while maintaining effective feedback management.

Inventive Principle:

Principle #16Partial or excessive action

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 approach enhances the stability of communication systems, reduces unwanted feedback and artifacts, and improves speech comprehensibility by aligning acoustic and visual localization, providing a more natural and comfortable conversation experience for passengers.

Implementation Method 1

stabilize electro-acoustic feedback loops

Methodology Applied

Scientific EffectAcoustic feedback: Feedback

Implementation Method 2

Combining active noise compensation with psycho-acoustic effects of spatial hearing to stabilize electro-acoustic feedback loops, reduce artifacts

Methodology Applied

Scientific EffectActive noise compensation: Interference

Implementation Method 3

at least one loudspeaker located in the room for converting electrical signals into acoustical signals

Methodology Applied

Scientific EffectElectro-acoustic conversion:

Implementation Method 4

at least one microphone located in the vicinity of each of the interlocutor positions in the room for generating electrical signals representative of acoustical signals

Methodology Applied

Scientific EffectAcoustic-to-electrical conversion:

Data Source

PatentUS8306234B2System for improving communication in a room

Publication Date: 2012.11.06 HARMAN BECKER AUTOMOTIVE SYST GMBH

AI summary

Improving the acoustical communication between interlocutors in at least two positions in a room includes generating electrical signals representative of acoustical signals present at the respective interlocutor positions, amplifying each of the electrical signals and converting the amplified electrical signals into acoustical signals. A time delay is applied to the electrical signals such that the acoustical signal arriving first at one of the interlocutor positions originates from the direction of the other interlocutor position.