Speakerphone Microphone Array Orientation and Vibration Isolation

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Solution Overview

Problem

Microphones in speakerphones face interference from the speaker and external vibrations, leading to phase problems and reduced audio quality due to their orientation and the materials used in their construction.

Innovation Solution

A speakerphone design featuring multiple vertically mounted microphones in a circular array with flexible microphone supports and a stiff internal speaker enclosure made of dense materials to minimize interference, with features like raised rims and internal ridges for increased stiffness, and omni-directional microphones oriented vertically to enhance sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If outward facing directional microphones with cardiod response are used, then interference from the speaker is reduced, but phase problems occur with incoming sound waves

Engineering Contradiction:

Improvespeaker interferenceVSAvoidphase accuracy

Core Design Contradiction:

Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The patent inverts the conventional microphone orientation by using inward-facing omnidirectional microphones instead of outward-facing directional microphones. This inversion allows the microphones to be positioned closer to the speaker while facing the center, eliminating phase problems with incoming sound waves while still reducing speaker interference through strategic positioning and acoustic design

Inventive Principle:

Principle #13The other way round (Inversion)

2Measurement precision

If microphones are mounted closer to the speaker, then audio reception is improved, but interference from speaker vibrations increases

Engineering Contradiction:

Improveaudio receptionVSAvoidvibration interference

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an acoustic isolation mechanism as an intermediary between the speaker and microphones. This includes using acoustic foam or porous materials in the speaker enclosure to absorb vibrations and prevent them from reaching the microphones, allowing close positioning without vibration interference

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs flexible vibration isolation mounts or dampening materials to mechanically isolate the microphones from speaker vibrations. These flexible elements absorb vibrational energy while allowing the microphones to remain positioned close to the speaker for optimal audio reception

Inventive Principle:

Principle #30Flexible shells and thin films

3Weight of moving object

If the speakerphone enclosure is made lighter, then portability is improved, but resistance to external vibrations decreases

Engineering Contradiction:

Improvespeakerphone weightVSAvoidexternal vibration sensitivity

Core Design Contradiction:

Weight of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent uses composite material structures combining lightweight materials (such as plastics or aluminum alloys) with strategically placed vibration-damping materials. This creates a lightweight overall structure that maintains vibration resistance through the damping layers, achieving both portability and vibration immunity

Inventive Principle:

Principle #40Composite 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

This design improves audio reception by reducing phase shifts and vibration-induced noise, resulting in enhanced microphone sensitivity and reduced interference from the speaker and external vibrations, leading to improved audio quality.

Implementation Method 1

The microphone support may be made of a flexible material and have various features designed to minimize interference to the microphone (e.g., from the speaker and/or vibrations external to the speakerphone)

Methodology Applied

Scientific EffectVibration isolation: Damping

Implementation Method 2

The speaker enclosure may be made of a stiff, heavy material (e.g., a dense plastic) to prevent the speaker vibrations from excessively vibrating the speakerphone enclosure (which may affect the microphones)

Methodology Applied

Scientific EffectVibration isolation: Damping

Data Source

PatentUS8116500B2Microphone orientation and size in a speakerphone

Publication Date: 2012.02.14 ENGHOUSE INTERACTIVE

AI summary

In various embodiments, a speakerphone may comprise multiple (e.g., 16) microphones placed in a circular array around a central speaker. The microphones may be mounted vertically in the speakerphone with their respective diaphragms substantially parallel to the top surface of the speakerphone. The centrally mounted speaker may be coupled to a stiff internal speaker enclosure. The speaker enclosure may be made of a stiff, heavy material (e.g., a dense plastic) to prevent the speaker vibrations from excessively vibrating the speakerphone enclosure (which may affect the microphones). The speaker enclosure may also include a raised rim and ridges to increase its stiffness.