Unidirectional Microphone Porous Ring Frequency Stabilization

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional unidirectional microphones face issues with maintaining stable frequency characteristics due to fixed distances between acoustic terminals, leading to decreased output in specific frequencies and increased likelihood of howling, and have high manufacturing costs due to complex housing modifications.

Innovation Solution

A unidirectional microphone unit with a porous ring member that adjusts sound wave routes by frequency, allowing for variable distances between acoustic terminals, reducing manufacturing costs by eliminating the need for housing modifications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the distance between acoustic terminals is fixed, then the microphone structure is simple, but frequency characteristics become unstable due to dips and peaks

Engineering Contradiction:

Improvemicrophone structureVSAvoidfrequency characteristics

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent introduces a movable partition wall that can shift positions to dynamically adjust the distance between acoustic terminals. This dynamic adjustment allows optimization of the distance for different frequency ranges, eliminating fixed-distance limitations and stabilizing frequency characteristics across the entire audible spectrum.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of distance between acoustic terminals from a fixed value to a variable value that can be adjusted according to frequency requirements. By making this parameter changeable, the system can adapt to different wavelength conditions and maintain stable frequency response without complex structural modifications.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the distance between acoustic terminals is adjusted to fix frequency issues, then frequency characteristics improve, but manufacturing cost increases due to complex housing modifications

Engineering Contradiction:

Improvefrequency characteristicsVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent segments the microphone housing into distinct functional sections: a front acoustic terminal section, a rear acoustic terminal section, and a movable partition wall. This segmentation allows independent optimization of each section and simplifies manufacturing by avoiding complex integrated modifications, while still achieving the desired frequency characteristic stabilization.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The movable partition wall acts as an intermediary element between the front and rear acoustic terminals. Instead of directly modifying the housing structure to adjust distances, the partition wall serves as a mediating component that can be independently positioned to achieve the optimal distance configuration, thereby reducing manufacturing complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Adaptability or versatility

If a directivity variable member is attached around the microphone case, then directivity can be adjusted, but the external size becomes large and high-frequency drive force decreases

Engineering Contradiction:

Improvedirectivity adjustmentVSAvoidexternal size

Core Design Contradiction:

Adaptability or versatilityVSLength of moving object

Solution Approach 1:

The patent merges the directivity adjustment function with the existing housing structure by integrating a movable partition wall into the housing. This consolidation eliminates the need for separate external directivity variable members, maintaining compact external dimensions while still providing adjustable directivity characteristics through the internal partition wall positioning.

Inventive Principle:

Principle #5Merging (Combining)

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 solution achieves stable frequency characteristics by suppressing dips and peaks, controlling output levels, and preventing howling, while reducing manufacturing costs and maintaining a compact size.

Implementation Method 1

the porous ring member 32 is provided in a front portion of the microphone unit 2, so that routes of sound waves are divided according to frequencies of sound waves

Methodology Applied

Scientific EffectAcoustic wave separation by frequency: Diffraction

Implementation Method 2

strength of resonance and a resonant frequency can be adjusted by setting of the height, an inner diameter, and a porosity of the ring member

Methodology Applied

Scientific EffectResonance: Resonance

Data Source

PatentUS9788102B2Unidirectional microphone unit

Publication Date: 2017.10.10 AUDIO TECHNICA CORP

AI summary

In a unidirectional microphone unit, stable frequency characteristics can be obtained, and manufacturing cost is reduced while preventing increasing of an external size. A microphone cap that covers a microphone element is included, and the microphone cap includes a porous ring member arranged in the front of the microphone element to form a first communication space communicating with a front acoustic hole in a center side, and a cylindrical member supporting a peripheral edge portion of the ring member and surrounding a periphery side of the microphone element, and forming a second communication space communicating with a rear acoustic hole in the periphery side of the microphone element, and the first communication space and the second communication space are communicated through the ring member.