Microphone Array AGC Using 3D Source Position for Stable Volume

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Solution Overview

Problem

Current automatic gain control systems in audio conferencing fail to provide consistent performance due to unknown sound source locations and ambient noise levels, leading to inconsistent volume and user experience in multi-user conference situations.

Innovation Solution

A system utilizing positional 3D spatial sound power information to calculate and control individual microphone gains based on known path loss calculations, ensuring consistent volume and stable ambient sound levels by determining the distance of sound sources and applying gain adjustments accordingly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If heuristic-based automatic gain control techniques are used to enhance audio conferencing system performance, then the system can handle variable sound levels, but the performance is not deterministic and ambient sound levels fluctuate inconsistently

Engineering Contradiction:

Improveability to handle variable sound levelsVSAvoiddeterministic performance

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The system uses feedback from the microphone array to continuously estimate sound source positions and adjusts gain parameters accordingly. The position estimator provides real-time feedback about sound source locations, enabling the automatic gain control to adapt deterministically based on actual acoustic conditions rather than relying on heuristic assumptions.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system dynamically changes the gain parameter based on the estimated position of sound sources. By calculating the distance between microphones and sound sources, the system adjusts the gain parameter to compensate for path loss, maintaining consistent sound levels regardless of source position while keeping ambient noise levels stable.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If automatic gain control adjusts gain based on unknown sound source positions, then the system can normalize volume levels, but the ambient sound levels also fluctuate and the system appears to hunt for the right gain setting

Engineering Contradiction:

Improvevolume level consistencyVSAvoidstable ambient sound levels

Core Design Contradiction:

Manufacturing precisionVSEase of operation

Solution Approach 1:

The system applies different gain adjustments to different microphone signals based on their respective positions relative to sound sources. Instead of applying a uniform gain change to all microphones, the system calculates position-specific gain parameters that normalize sound source volumes while maintaining stable ambient noise levels across all microphone channels.

Inventive Principle:

Principle #3Local quality

3Adaptability or versatility

If heuristic automatic gain control operates without knowing sound source distance, then the system can function in multi-user situations, but the performance varies and user experience is inconsistent

Engineering Contradiction:

Improvemulti-user situation handlingVSAvoidsound source position awareness

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The system replaces mechanical position measurement devices with an acoustic position estimation algorithm. By analyzing the signals from the microphone array and applying signal processing techniques, the system determines sound source positions computationally, enabling precise gain control without physical position sensors while maintaining consistent performance in multi-user situations.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS11635937B2Method, apparatus and computer-readable media utilizing positional information to derive AGC output parameters

Publication Date: 2023.04.25 NUREVA INC

AI summary

Method and apparatus for automatic gain control utilizing sound source position information in a shared space having a plurality of microphones and a plurality of sound sources. Sound signals are received from the microphones. One or more processors locate position information corresponding to each of the sound sources. The processor(s) determine the distance to each of the sound sources from each of the microphones. The processor(s) define a predetermined gain weight adjustment for each of the microphones. The processor(s) apply the defined weight adjustments to the microphones to achieve a consistent volume of the desired plurality of sound sources. The processor(s) maintain a consistent ambient sound level regardless of the position of the sound sources and the applied gain weight adjustments. The processor(s) output a summed signal of the sound sources at a consistent volume with a constant ambient sound level across the plurality of sound source positions.