Headset Branch Pipe for Passive Noise Reduction

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Solution Overview

Problem

Existing headsets struggle to effectively isolate noise from the external environment, which interferes with the sound quality of audio signals, leading to a need for improved noise reduction techniques.

Innovation Solution

The implementation of a headset design featuring a sound cavity with a branch pipe that connects the front and rear cavities to the external environment, allowing low-band sound waves to pass through while filtering out high-band noise, and incorporating a microporous channel for acoustic damping to stabilize sound pressure levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the sound cavity is completely sealed to isolate external noise, then noise isolation is improved, but atmospheric pressure cannot be balanced causing diaphragm reliability to deteriorate

Engineering Contradiction:
Improvenoise isolationVSAvoiddiaphragm reliability
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent applies local quality by creating different acoustic characteristics in different parts of the sound cavity. The branch pipe with specific impedance characteristics is introduced at a localized position to balance atmospheric pressure, while the main sound cavity remains sealed for noise isolation. This allows different regions to have different acoustic properties - the sealed cavity provides noise isolation while the branch pipe provides pressure equalization.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The branch pipe acts as an intermediary element between the sealed sound cavity and the external environment. It mediates the conflict between noise isolation and pressure balancing by providing a controlled acoustic pathway that allows pressure equalization while maintaining the sealed structure for noise isolation. The pipe's impedance characteristics filter the interaction between the cavity and external environment.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the sound cavity is opened to the external environment to balance pressure, then diaphragm reliability is improved, but noise isolation deteriorates

Engineering Contradiction:
Improvediaphragm reliabilityVSAvoidnoise isolation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

Instead of uniformly opening the sound cavity, the patent introduces a localized branch pipe with specific acoustic impedance characteristics. This creates a selective pathway that allows pressure equalization while maintaining noise isolation in the main cavity. The local modification at the branch pipe position provides the necessary pressure balancing without compromising overall noise isolation.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The branch pipe system effectively creates a controlled porous-like pathway for acoustic waves. The pipe's dimensions and impedance characteristics create a frequency-selective pathway that allows low-frequency pressure waves to pass through while blocking high-frequency noise, similar to how porous materials selectively transmit different frequency components.

Inventive Principle:
Principle #31Porous materials

3Object-affected harmful factors

If acoustic resistive material is added to reduce noise, then noise isolation is improved, but sound quality deteriorates

Engineering Contradiction:
Improvenoise isolationVSAvoidsound quality
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent applies local quality by introducing acoustic resistive material only in the branch pipe rather than throughout the entire sound cavity. This localized application provides noise reduction in the frequency ranges where the branch pipe is most effective, while preserving sound quality in the main cavity where the driver operates. The material is strategically placed to target specific frequency components without affecting overall audio fidelity.

Inventive Principle:
Principle #3Local quality

4Object-affected harmful factors

If the branch pipe is made longer to improve low-pass filtering, then noise isolation is improved, but device complexity increases

Engineering Contradiction:
Improvenoise isolationVSAvoidstructure complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by optimizing the branch pipe's dimensional parameters (length, diameter, shape) to achieve the desired low-pass filtering effect. By carefully selecting these parameters, the design achieves effective noise isolation without requiring excessive pipe length. The parameters are tuned to provide the necessary acoustic impedance characteristics that create the low-pass filter effect while maintaining a compact structure.

Inventive Principle:
Principle #35Parameter changes

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

This design achieves a significant passive noise reduction effect, improving acoustic comfort and reliability of the diaphragm by balancing atmospheric pressures and reducing noise interference, resulting in more stable sound pressure and phase responses across various frequency bands.

Implementation Method 1

the branch pipe connects the front cavity, the rear cavity, and an external environment... allow a low-band sound wave entering from the external environment to pass through and filter out a high-band sound wave entering from the external environment

Methodology Applied
Scientific EffectAcoustic filtering: Filter (physical)

Implementation Method 2

incorporating a microporous channel for acoustic damping to stabilize sound pressure levels

Methodology Applied
Scientific EffectAcoustic damping: Damping

Implementation Method 3

the driver is configured to: receive an audio signal, and convert the audio signal into a sound wave

Methodology Applied
Scientific EffectElectroacoustic transduction:

Data Source

PatentEP4030778B1headset
Publication Date: 2024.11.27 HUAWEI TECH CO LTD
  • EP4030778B1 patent drawingFigure 1
  • EP4030778B1 patent drawingFigure 2
  • EP4030778B1 patent drawingFigure 3~4

AI summary

Embodiments of this application disclose a noise reduction headset. A branch pipe is disposed in the headset to connect a sound cavity inside the headset and an external environment. The branch pipe has a low-pass filter function to filter out high-band noise entering the sound cavity from the external environment, so that impact on sound quality inside the sound cavity that is caused by noise in the external environment is reduced, thereby implementing passive noise reduction.