Auto-calibrating In-ear Headphone with Ear Canal Feedback

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Solution Overview

Problem

Existing in-ear headphones fail to provide accurate frequency responses and ambient noise transmission due to individual ear anatomy variations, leading to suboptimal sound reproduction and incomplete noise cancellation, especially in environments where background noises are necessary for safety.

Innovation Solution

An auto-calibrating in-ear headphone system that uses an integrated circuit to generate sound signals, measure ear canal characteristics, and modify audio signals based on ear drum responses and target functions, allowing for accurate sound reproduction and ambient noise integration without removing the headphones.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If in-ear headphones create a closed seal with the ear canal to block environmental noises, then active noise cancellation is improved, but the user cannot hear environmental background noises necessary for safety

Engineering Contradiction:
Improveenvironmental noise blockingVSAvoidisolation from necessary environmental sounds
Core Design Contradiction:
Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The system dynamically switches between different operational modes (noise cancellation mode and ambient sound mode) based on user needs and environmental conditions, making the noise isolation特性 adjustable rather than fixed

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

A microphone acts as an intermediary to capture environmental sounds outside the ear canal and transmit them to the user's ear, bridging the gap between the sealed ear canal and the external environment

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If conventional headphones use flat frequency response equalization, then manufacturing complexity is reduced, but individual ear anatomy variations cause inaccurate sound reproduction

Engineering Contradiction:
Improveequalization simplicityVSAvoidfrequency response accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The system performs self-calibration by automatically measuring the user's ear canal characteristics through built-in microphones and speakers, eliminating the need for external measurement equipment or manual equalization setup

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system uses feedback from microphones that detect sounds played through the ear canal to automatically adjust and optimize the frequency response equalization for each user's unique ear anatomy

Inventive Principle:
Principle #23Feedback

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 ensures users experience intended sound frequencies and ambient noises as if not wearing headphones, with efficient active noise cancellation, addressing individual ear anatomy variations and enhancing safety in noisy environments.

Implementation Method 1

generate a sound signal and play the sound signal at a driver when the in-ear headphone is placed in a user's ear canal

Methodology Applied
Scientific EffectSound wave propagation: Sound

Implementation Method 2

the reflected sound signal is received and recorded by a first microphone

Methodology Applied
Scientific EffectAcoustic reflection: Reflection

Implementation Method 3

An integrated circuit within an in-ear headphone can generate a sound signal and play the sound signal at a driver

Methodology Applied
Scientific EffectAcoustic signal processing:

Implementation Method 4

generate a second sound signal from an audio input and modify the second sound signal based on the user's ear drum response

Methodology Applied
Scientific EffectFrequency response equalization:

Implementation Method 5

in-ear headphones are known to provide high quality sound to a user by creating a closed seal with the ear drum and the outside world, thereby blocking out most environmental or background noises

Methodology Applied
Scientific EffectAcoustic absorption: Acoustic Absorption

Data Source

PatentEP3917155B1Auto-calibrating in-ear headphone
Publication Date: 2023.11.08 HARMAN INT IND INC
  • EP3917155B1 patent drawingFigure 1
  • EP3917155B1 patent drawingFigure 2
  • EP3917155B1 patent drawingFigure 3

AI summary

A method for calibrating an in-ear headphone to improve the frequency response heard by a user. The method including generating a sound signal and playing the sound signal at a driver when the in-ear headphone is placed within a user's ear canal, receiving a reflected sound signal at a first microphone, generating a frequency response based on the reflected sound signal, generating the user's ear drum response based on the frequency response, generating a second sound signal, modifying the second sound signal based on the user's ear drum response, and playing the modified second sound signal at the driver.