Vehicle Audio Loudness Control With Speed-Based Low-Frequency Gain

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Solution Overview

Problem

Existing audio systems in vehicles fail to optimally adjust low frequencies due to increased noise and vibrations at higher speeds, making them less perceptible, and existing systems apply the same volume increment factor across all frequencies, resulting in a less than ideal in-vehicle sound experience.

Innovation Solution

A device and method for adjusting the volume of audio signals in vehicles that separately adjust the volume of low frequencies and overall audio signals based on vehicle speed, using different volume increment factors for loudspeakers and tactile transducers, with adjustments stored in tables for quick implementation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the same volume increment factor is applied to all frequencies, then the audio signal is amplified uniformly, but low frequencies cannot be optimally differentiated and adjusted separately from high frequencies

Engineering Contradiction:
Improvefrequency-specific volume adjustmentVSAvoidvolume adjustment system
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The audio signal is segmented into different frequency ranges (low frequencies and high frequencies) using filter units. Each frequency segment is then processed independently with its own volume increment factor, allowing low frequencies to be adjusted separately from high frequencies based on their specific perceptibility characteristics at different vehicle speeds

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different volume increment factors are applied to different frequency ranges based on their local characteristics. Low frequencies (100-500 Hz) receive a first volume increment factor while other frequencies receive a second volume increment factor, optimizing the adjustment for each frequency band's specific perceptibility issues

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If low frequencies are amplified at high speeds, then they become more audible, but the system cannot provide differentiated optimization for low and high frequencies

Engineering Contradiction:
Improvelow frequency perception optimizationVSAvoidfrequency differentiation capability
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The audio signal is segmented into different frequency ranges (low frequencies and high frequencies) using filter units. Each frequency segment is then processed independently with its own volume increment factor, allowing low frequencies to be adjusted separately from high frequencies based on their specific perceptibility characteristics at different vehicle speeds

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system changes the parameter of volume increment factor based on frequency range and vehicle speed. Low frequencies receive a first volume increment factor while other frequencies receive a second volume increment factor, with these factors being selectable based on the current speed of the vehicle to optimize low frequency perception

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If a single audio signal adjustment is applied, then the system is simple to operate, but it cannot separately optimize low frequencies and overall audio signal

Engineering Contradiction:
Improveseparate low frequency adjustmentVSAvoidvolume control system
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The audio signal is segmented into different frequency ranges (low frequencies and high frequencies) using filter units. Each frequency segment is then processed independently with its own volume increment factor, allowing low frequencies to be adjusted separately from high frequencies based on their specific perceptibility characteristics at different vehicle speeds

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The control unit automatically determines the appropriate volume increment factors and applies them based on the current speed of the vehicle, eliminating the need for manual adjustment by the user while providing optimized low frequency perception across different driving conditions

Inventive Principle:
Principle #25Self-service

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

Enhances the perception of low frequencies and overall audio quality by compensating for noise and vibrations at varying speeds, providing an optimized in-vehicle sound experience.

Implementation Method 1

tactile transducers, also known as shakers or bass shakers. These can be installed in the vehicle's seats and convert low frequencies (bass frequencies) into structure-borne sound via the surface to which they are mounted

Methodology Applied
Scientific EffectElectromechanical transduction:

Data Source

PatentEP4661290A1Device for adapting the loudness of an audio signal in an audio system of a motor vehicle
Publication Date: 2025.12.10 BAYERISCHE MOTOREN WERKE AG
  • EP4661290A1 patent drawingFigure 1
  • EP4661290A1 patent drawingFigure 2
  • EP4661290A1 patent drawingFigure 3

AI summary

A device for adjusting the volume of an audio signal in an audio system of a motor vehicle is proposed, wherein the audio system has an input for receiving the audio signal from an input source and an output for outputting the audio signal, wherein the volume of the audio signal is adjustable by means of a control of the audio system, wherein the device has a control unit configured to determine an audio signal gain based on the current volume of the audio signal and based on a current speed of the motor vehicle, to determine a first volume increment factor based on the set volume, and to adjust the volume of the audio signal using the audio signal gain and the first volume increment factor.The control unit is further designed to determine a low-frequency gain based on the current speed of the vehicle, to determine a second volume increment factor based on the set volume, and to adjust the low-frequency volume of the audio signal using the low-frequency gain and the second volume increment factor, and/or the control unit is designed to adjust an audio signal output via the vehicle's structure-borne sound transducers based on the current speed of the vehicle using a structure-borne sound transducer parameter.