Automatic Audio Equalization Using Microphone Phase Differences

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Solution Overview

Problem

Manual audio equalization is cumbersome and requires significant user knowledge, making it difficult for average users to achieve high-quality audio output in various room environments without repeated setup and calibration.

Innovation Solution

An automated audio equalization system using microphones integrated into electronic devices, which measure phase differences and relative amplitudes to adjust frequency responses without user input, employing machine learning and acoustical models to learn and correct for room positions and reflections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If manual audio equalization is performed, then audio output quality can be improved, but user time and effort are significantly increased

Engineering Contradiction:
Improveaudio output qualityVSAvoiduser time and effort
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The system uses the electronic device's own microphones to capture audio output and automatically perform equalization adjustments without requiring external measurement equipment or user intervention. The device self-calibrates by analyzing its own acoustic environment and applying corrections autonomously.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces the manual mechanical process of equalization adjustment with an automated computational system. Machine learning models and acoustic transfer function calculations substitute for manual tuning, converting a labor-intensive process into an automatic computational task.

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

2Manufacturing precision

If manual audio equalization is performed, then audio output quality can be improved, but user knowledge requirements are significantly increased

Engineering Contradiction:
Improveaudio output qualityVSAvoiduser knowledge requirements
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The system performs equalization automatically using built-in microphones and processing algorithms, eliminating the need for users to understand acoustic theory, measurement techniques, or equalization concepts. The device handles the entire process independently.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent introduces machine learning models and acoustic transfer function calculations as intermediaries between the raw audio output and the final equalized signal. These computational layers translate complex acoustic measurements into automatic adjustments, shielding users from technical complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Manufacturing precision

If manual equalization is performed, then audio quality can be adjusted for specific room conditions, but the process must be repeated when room or placement changes

Engineering Contradiction:
Improveaudio qualityVSAvoidadaptability to room changes
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The system continuously monitors the acoustic environment using the electronic device's microphones and dynamically adjusts equalization parameters in real-time. This continuous adaptation ensures optimal audio quality regardless of changes in room conditions or device placement, eliminating the need for repeated manual calibration.

Inventive Principle:
Principle #20Continuity of useful action

4Extent of automation

If automated audio equalization is implemented, then user interaction is eliminated, but system complexity is increased

Engineering Contradiction:
Improveuser interaction requirementVSAvoidsystem complexity
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The patent leverages the electronic device's existing microphones, which were originally designed for other purposes (such as voice recognition or environmental sound capture), and repurposes them for acoustic measurement and equalization. This multi-functional use of existing components automates equalization without adding dedicated hardware.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

Enables high-quality audio output automatically, independent of user interaction, by continuously adapting to changes in room environments and device positions, improving listening experiences without the need for manual calibration.

Implementation Method 1

obtain a collection of audio content signals including receiving outputted audio content at each microphone of the plurality of microphones

Methodology Applied
Scientific EffectAcoustic wave propagation: Sound

Implementation Method 2

determine from the collection of audio content signals a plurality of phase differences between microphones of the plurality of microphones

Methodology Applied
Scientific EffectPhase difference measurement: Interference

Implementation Method 3

obtain a frequency correction from a correction database based on the determined acoustic transfer function and based on the obtained feature vector; applying the obtained frequency correction to the subsequent audio output

Methodology Applied
Scientific EffectFrequency response adjustment: Resonance

Data Source

PatentUS11005440B2Methods and systems for automatically equalizing audio output based on room position
Publication Date: 2021.05.11 GOOGLE LLC
  • US11005440B2 patent drawing
  • US11005440B2 patent drawing
  • US11005440B2 patent drawing

AI summary

The various implementations described herein include methods, devices, and systems for automatic audio equalization. In one aspect, a method is performed at an electronic device that includes speakers, microphones, processors and memory. The electronic device outputs audio user content from the speakers and automatically equalizes subsequent audio output of the device without user input. The automatic equalization includes: (1) obtaining audio content signals, including receiving outputted audio content at each microphone; (2) determining from the audio content signals phase differences between microphones; (3) obtaining a feature vector based on the phase differences; (4) obtaining a frequency correction from a correction database based on the obtained feature vector; and (5) applying the obtained frequency correction to the subsequent audio output.