Automatic Room Equalization Using Built-In Speakers and Microphones

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Solution Overview

Problem

Manual audio equalization is cumbersome and requires specialized knowledge, making it difficult for average users to achieve consistent audio quality across different room environments and speaker placements.

Innovation Solution

Electronic devices with integrated microphones automatically equalize audio output by analyzing phase differences and room characteristics using machine learning, without user interaction, to correct for room effects on sound quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If manual audio equalization is performed, then audio quality can be improved, but the process becomes cumbersome and time-consuming requiring specialized knowledge

Engineering Contradiction:
Improveaudio qualityVSAvoiduser operation
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The system performs automatic audio equalization by having the device play test tones and using its own microphone to capture the acoustic response of the room. The processor automatically analyzes the captured signal, determines room transfer functions, and applies corrections without requiring user intervention or specialized knowledge about audio equipment and room acoustics.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system automatically adjusts audio parameters (frequency response, gain) based on measured room characteristics. By changing the operational parameters of the audio output based on real-time measurements of the acoustic environment, the system adapts to different room conditions and placements without manual configuration.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If manual equalization is performed, then consistent audio quality across different rooms can be achieved, but it requires repeated setup and calibration

Engineering Contradiction:
Improveaudio quality consistencyVSAvoidsetup time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary measurements by playing test tones and capturing room responses before actual audio playback. This preliminary characterization of the room's acoustic properties enables the system to pre-compute correction filters that will be applied during normal operation, ensuring consistent quality without requiring repeated manual setup when the device is moved to different locations.

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If automatic equalization is implemented, then user convenience is improved, but the device complexity increases

Engineering Contradiction:
Improveuser convenienceVSAvoidsystem complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The system uses the device's existing speakers and microphones for multiple purposes - both for normal audio playback/recognition and for acoustic measurement. This multi-functionality eliminates the need for separate dedicated measurement hardware, reducing overall system complexity while enabling automatic equalization capabilities.

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

Solution Approach 2:

The system replaces complex manual mechanical adjustment procedures (physical equalization controls, microphone positioning) with automated electronic signal processing. The processor automatically performs tasks that would otherwise require manual mechanical adjustment, simplifying the user interface while managing the complexity through software-based solutions.

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

4Manufacturing precision

If room acoustic measurement is performed, then audio output quality is improved, but the measurement process requires user action

Engineering Contradiction:
Improveaudio output qualityVSAvoidmeasurement process
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The device performs self-measurement by autonomously playing test tones and capturing its own acoustic output through its microphone. This self-service approach eliminates the need for users to manually position external measurement microphones or operate separate measurement tools, making the measurement process as simple as pressing a button while maintaining high audio output quality through accurate room characterization.

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

Provides high-quality audio experiences across varying room conditions without the need for manual setup or calibration, enhancing user convenience and satisfaction.

Implementation Method 1

output by the speaker first audio content and receive by the microphone an indication of the first audio content

Methodology Applied
Scientific EffectSound propagation: Sound

Implementation Method 2

A mapping is applied to the first acoustic response to determine a second acoustic response. The second acoustic response is indicative of an approximated acoustic response of the room at a spatial location different from a spatial location of the microphone

Methodology Applied
Scientific EffectAcoustic mapping:

Implementation Method 3

The second audio content output by the speaker is adjusted based on the second response

Methodology Applied
Scientific EffectAudio equalization:

Data Source

PatentEP3692634B1Methods and systems for automatically equalizing audio output based on room characteristics
Publication Date: 2025.09.10 GOOGLE LLC
  • EP3692634B1 patent drawingFigure 1A~1B
  • EP3692634B1 patent drawingFigure 2
  • EP3692634B1 patent drawingFigure 3A

AI summary

The various implementations described herein include methods, devices, and systems for automatic audio equalization, in one aspect, a method is performed at a computing system that includes speaker(s), microphones, processors and memory. The computing system outputs audio user content and automatically equalizes the audio output of the computing system. The equalizing includes; (1) receiving the outputted audio content at each microphone of the plurality of microphones; (2) based on the received audio content, determining an acoustic transfer function for the room; (3) based on the determined acoustic transfer function, obtaining a frequency response for the room; and (4) adjusting one or more properties of the speakers based on the determined frequency response.