Road Alert Loudspeaker Beamforming for In-Car Speech Intelligibility

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Solution Overview

Problem

Conventional road alert systems face challenges in achieving both adequate speech intelligibility and reducing noise pollution, often requiring bulky equipment and high sound pressure levels, which compromise portability, energy efficiency, and cost-effectiveness, while also causing excessive noise pollution in surrounding areas.

Innovation Solution

A road alert system employing a loudspeaker array with a controller that applies equalization parameters and beamforming to optimize in-vehicle speech intelligibility and minimize noise pollution by focusing audio output on the vehicle while reducing dispersion into surrounding areas.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional loudspeaker arrays transmit audio output at high sound pressure levels to improve speech intelligibility, then in-vehicle speech intelligibility is improved, but noise pollution in surrounding areas increases

Engineering Contradiction:
Improvespeech intelligibilityVSAvoidnoise pollution
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The system applies different acoustic characteristics to different spatial zones: the audio output is optimized for intelligibility within the vehicle's local zone while being suppressed in surrounding areas. The controller adjusts equalization parameters specifically tailored to the vehicle's acoustic environment, creating localized quality improvement without widespread noise pollution.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system dynamically adapts the audio transmission characteristics based on real-time conditions. The controller modifies equalization parameters and beamforming patterns according to the vehicle's position, speed, and acoustic environment, allowing the system to optimize speech intelligibility when the vehicle is present while minimizing noise pollution when the vehicle is absent or moving away.

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If conventional road alert systems use multiple loudspeaker arrays to ensure adequate speech intelligibility, then speech coverage is improved, but device complexity and cost increase

Engineering Contradiction:
Improvespeech intelligibilityVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

Instead of adding more loudspeaker arrays, the system achieves improved speech intelligibility by changing the parameters of the existing single array. The controller adjusts equalization parameters, gain settings, and beamforming patterns to optimize the acoustic output for the specific vehicle environment, extracting maximum performance from the existing hardware configuration.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If conventional systems increase sound pressure level to overcome road noise, then speech intelligibility is improved, but energy consumption increases

Engineering Contradiction:
Improvespeech intelligibilityVSAvoidenergy consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The system changes the frequency distribution parameters through equalization rather than uniformly increasing sound pressure level across all frequencies. By applying targeted gain adjustments to specific frequency bands where speech intelligibility is most critical, the system achieves better speech understanding with lower overall energy consumption compared to blanket amplification approaches.

Inventive Principle:
Principle #35Parameter changes

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 improved in-car speech intelligibility with reduced noise pollution, enhancing portability, energy efficiency, and cost-effectiveness by using specialized speaker tuning and array beamforming to control audio directionality and minimize unwanted reflections.

Implementation Method 1

transmitting the audio output signal via the loudspeaker array in a beamforming mode to minimize noise pollution for objects positioned along the road

Methodology Applied
Scientific EffectBeamforming: Focusing

Implementation Method 2

applying equalization parameters to the message to increase in-vehicle speech intelligibility of the audio output signal within the vehicle

Methodology Applied
Scientific EffectEqualization:

Data Source

PatentEP4198977B1System and method for road alert systems to improve in-car speech intelligibility and reduce noise pollution
Publication Date: 2025.12.31 HARMAN INT IND INC
  • EP4198977B1 patent drawingFigure 1~2
  • EP4198977B1 patent drawingFigure 3
  • EP4198977B1 patent drawingFigure 4~5

AI summary

In at least one embodiment, a road alert system is provided. The system includes a loudspeaker array and at least one controller. The loudspeaker array transmits an audio output signal to a vehicle traveling on a road. The at least one controller is programmed to receive a message indicative of a warning for the vehicle for transmission on the audio output signal and to apply equalization parameters to the message to increase in-vehicle speech intelligibility of the audio output signal within the vehicle. The at least one controller is further programmed to transmit the audio output signal via the loudspeaker array in a beamforming mode to minimize noise pollution for objects positioned along the road.