Boundary Binaural Microphone Array for Conference Audio

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Solution Overview

Problem

Conventional binaural microphone configurations for remote meetings can be uncomfortable for local attendees and reduce intelligibility due to sound reflections from surfaces, especially when microphones are placed above a conference table.

Innovation Solution

A boundary binaural microphone array with a pair of microphones spaced 5 cm to 30 cm apart, supported closely above a surface with a sound barrier to create interaural level differences, reducing sound reflections and enhancing signal intelligibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If microphones are placed inside dummy heads for binaural recording, then audio intelligibility for remote attendees is improved, but local attendees experience discomfort due to the physical presence of dummy heads at the conference table

Engineering Contradiction:

Improveaudio intelligibilityVSAvoidcomfort for local attendees

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The patent creates an artificial boundary surface that replicates the acoustic effect of a human head and ears without using an actual dummy head. The boundary surface at z=0 with specific impedance properties copies the acoustic behavior of a binaural setup, eliminating the need for physical dummy heads while maintaining the interaural level difference effect for improved audio intelligibility.

Inventive Principle:

Principle #26Copying

2Measurement precision

If microphones are placed more than 4 cm above the table surface, then they capture direct sound better, but they pick up sound reflections from the table that reduce intelligibility

Engineering Contradiction:

Improvedirect sound captureVSAvoidsound reflections

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful table surface into a beneficial acoustic boundary by treating it as a pressure release boundary (z=0 plane). Instead of trying to avoid the table surface, the invention uses it to create the desired acoustic effect of a boundary that generates interaural level differences, turning the reflection problem into the solution mechanism.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Measurement precision

If microphones are spaced far apart to improve binaural effect, then interaural level difference increases, but the device becomes more complex and harder to position stably

Engineering Contradiction:

Improveinteraural level differenceVSAvoidmicrophone array configuration

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent makes the boundary surface itself serve multiple functions: it acts as the support structure, creates the acoustic boundary condition, generates the interaural level difference effect, and positions the microphones. By placing microphones symmetrically above the boundary surface, the system achieves the binaural effect with a compact, stable configuration that doesn't require complex positioning mechanisms.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 provides improved audio intelligibility for remote attendees while minimizing discomfort for local participants by reducing sound reflections and maintaining effective speech capture across various frequency bands.

Implementation Method 1

The microphones are separated by a sound barrier that provides an interaural level difference in the amplitudes of the sound signals sensed by the two microphones

Methodology Applied

Scientific EffectSound barrier: Absorption (physical)

Implementation Method 2

the microphones are located no more than approximately 4 cm off of a surface upon which the array is placed... the microphones pick up sound reflections from the table. That is, if someone in the conference room is speaking, the microphone picks up the voice directly from the speaker as well as reflections of the voice off of the table top

Methodology Applied

Scientific EffectSound reflection reduction: Acoustic Absorption

Data Source

PatentUS9516417B2Boundary binaural microphone array

Publication Date: 2016.12.06 MICROSOFT TECHNOLOGY LICENSING LLC

AI summary

A boundary binaural microphone array includes a pair of microphones spaced from one another by a distance between approximately 5 cm and 30 cm. The boundary binaural microphone array has a structural support that locates the microphones no more than approximately 4 cm off of a surface upon which the array is placed. The microphones are separated by a sound barrier that provides an interaural level difference in the amplitudes of the sound signals sensed by the two microphones.