Radio Microphone Acoustic Chamber Foam for Reflection Control

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Solution Overview

Problem

Handheld radio transceivers experience reduced audio quality due to microphone placement inside the device and carrying position, leading to ambient noise and sound reflections, which existing solutions fail to adequately address without separating the microphone from the transceiver.

Innovation Solution

A microphone arrangement with an acoustic chamber, sound channel, cover, and a mechanically flexible foam element inserted in the chamber to reduce sound reflections, using a closed cell polychloroprene foam to fill gaps and prevent scattering, with a sound conducting channel and watertight seal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the microphone is placed inside the radio transceiver for protection, then the device structure is simplified and manufacturing is easier, but the audio quality deteriorates due to sound reflections and ambient noise

Engineering Contradiction:
Improvemicrophone placement simplicityVSAvoidsound reflections and ambient noise
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a foam element with porous structure into the acoustic chamber. This foam material absorbs sound waves and prevents reflections from the chamber walls, thereby reducing ambient noise and improving audio quality while keeping the microphone inside the protected transceiver housing.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The foam element acts as an intermediary between the microphone and the acoustic chamber walls. It mediates the sound propagation by absorbing reflected sound waves, preventing them from reaching the microphone and degrading the audio signal.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If the microphone is placed closer to the user's mouth outside the device, then audio quality improves, but the device structure becomes more complex and protection is reduced

Engineering Contradiction:
Improvespeech signal qualityVSAvoidmicrophone arrangement structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

By using porous foam material inside the acoustic chamber, the patent achieves sound absorption and reflection reduction without moving the microphone outside the device. This maintains the simple integrated structure while improving audio quality comparable to external microphone placement.

Inventive Principle:
Principle #31Porous materials

3Ease of manufacture

If the acoustic chamber is left empty or with minimal filling, then manufacturing is easier and cost is lower, but sound reflections and scattering increase

Engineering Contradiction:
Improveacoustic chamber assemblyVSAvoiddiffuse scattering of sound
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The foam element provides effective sound absorption with minimal structural complexity. It can be easily inserted into the acoustic chamber during assembly, requiring no complex manufacturing processes, while effectively preventing diffuse scattering of sound waves.

Inventive Principle:
Principle #31Porous materials

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

Enhances sound quality by preventing sound reflections and scattering within the acoustic chamber, improving speech quality by guiding audio signals directly to the microphone without gaps or contamination.

Implementation Method 1

a foam element which is inserted in the acoustic chamber in order to reduce sound reflections in the acoustic chamber

Methodology Applied
Scientific EffectSound absorption: Acoustic Absorption

Data Source

PatentEP4117302B1Microphone arrangement for a radio device
Publication Date: 2026.01.28 ROHDE & SCHWARZ GMBH & CO KG
  • EP4117302B1 patent drawingFigure 1
  • EP4117302B1 patent drawingFigure 2
  • EP4117302B1 patent drawingFigure 3

AI summary

The invention relates to a microphone arrangement (10) for a radio device (60). The microphone arrangement (10) comprises an acoustic chamber (12) which is arranged within a housing (1) of the radio device (60); a sound channel (11) which is arranged to connect the acoustic chamber (12) to an outside of the housing (1); a cover (2) which is arranged between the acoustic chamber (12) and the sound channel (11); a microphone (4) which is arranged in the acoustic chamber (12); and a foam element (3) which is inserted in the acoustic chamber (12) in order to reduce sound reflections in the acoustic chamber (12) .