Loudspeaker Performance Profiling for THD-Aware Sound Field Tuning

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Solution Overview

Problem

Conventional acoustic systems lack accurate methods for automated tuning, particularly in determining total harmonic distortion (THD) and sound pressure level (SPL) data, leading to sub-optimal performance and potential speaker damage due to non-linear behavior at different sound pressure levels.

Innovation Solution

A method and system for determining loudspeaker performance profiles based on automatically acquired THD and SPL data, using these profiles to adapt sound field management by optimizing cross-over filter settings and equalizer filters, ensuring optimal performance across varying sound pressure levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If automated tuning methods are used for acoustic systems, then productivity is improved, but measurement precision deteriorates due to inaccurate THD and SPL data

Engineering Contradiction:
Improveautomated tuningVSAvoidTHD and SPL data accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The system performs preliminary measurements of THD and SPL across multiple frequency points and amplifier gain values before generating the performance profile. This preliminary action ensures accurate baseline data is captured, which then enables precise automated tuning without requiring repeated measurements during the tuning process itself.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically adapts the tuning parameters based on the measured THD and SPL data. The performance profile is created by measuring at multiple amplifier gain values and frequencies, then using this dynamic data to adjust cross-over filter settings and equalizer filters, making the tuning process both automated and precision-oriented.

Inventive Principle:
Principle #15Dynamics

2Device complexity

If conventional tuning methods are used, then device complexity is reduced, but reliability worsens due to potential speaker damage from non-linear behavior

Engineering Contradiction:
Improvetuning systemVSAvoidspeaker protection
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The system uses feedback by measuring THD and SPL data from the actual loudspeaker performance, then using this feedback to create an accurate performance profile. This profile informs subsequent tuning decisions, allowing the system to adjust settings based on real performance data, preventing conditions that could lead to speaker damage while maintaining appropriate complexity for reliable operation.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system changes parameters by measuring at multiple amplifier gain values and frequency points to capture the non-linear behavior of loudspeakers. This comprehensive parameter measurement creates a detailed performance profile that enables reliable tuning decisions, protecting speakers from operating conditions that would cause damage while maintaining necessary system complexity.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If detailed THD and SPL measurements are performed across multiple frequencies and gain values, then manufacturing precision is improved, but loss of time increases

Engineering Contradiction:
Improveperformance profile accuracyVSAvoidmeasurement time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The system performs the time-consuming measurements of THD and SPL across multiple frequencies and gain values as a preliminary action during the initial setup phase. Once the performance profile is created from this comprehensive data, automated tuning can proceed quickly using the pre-captured information, reducing time loss in subsequent tuning operations while maintaining high manufacturing precision in the profile accuracy.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4672784A1A method and a system for determining a loudspeaker performance profile for sound field management of an acoustic system
Publication Date: 2025.12.31 HARMAN BECKER AUTOMOTIVE SYST GMBH
  • EP4672784A1 patent drawingFigure 1
  • EP4672784A1 patent drawingFigure 2a
  • EP4672784A1 patent drawingFigure 2b~2c

AI summary

A method carried out at a processing entity is provided. The method comprises determining, for each loudspeaker of an acoustic system comprising multiple loudspeakers, sound pressure level, SPL, data and total harmonic distortion, THD, data over different frequencies and different amplifier gain values associated with different SPLs. The method further comprises determining, for each loudspeaker based on the THD and the SPL data, a loudspeaker performance profile forming a plurality of loudspeaker performance profiles; and providing the plurality of loudspeaker performance profiles for an adaptation of a sound field generated by the acoustic system.