Microphone Balance Gain Control for Stable Spatial Sound Fields
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Solution Overview
Problem
Existing sound field processing systems using multiple microphones often lose spatial information due to noise suppression processes, resulting in a mono output signal that lacks spatial information.
Innovation Solution
A system and method that calculate balance gains for each microphone signal, adjust gains based on background noise estimates and echo cancellation processes, and use spectral coherence to prevent high-frequency attenuation and enhance low-frequency signals, while blending signals to mitigate structured noise and preserve spatial stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If noise suppression processes are applied to multiple microphone signals, then noise performance is improved, but spatial information is lost resulting in mono output
Solution Approach 1:
The patent segments the noise suppression process by applying different processing paths to different frequency components. Low-frequency signals undergo noise suppression while high-frequency signals preserve their original spatial characteristics, thus maintaining spatial information while improving noise performance.
Solution Approach 2:
The patent applies local quality by treating different frequency bands differently: low-frequency components receive noise suppression processing while high-frequency components maintain their original spatial properties. This localized approach ensures noise reduction where needed without sacrificing spatial information in critical frequency ranges.
2Object-affected harmful factors
If gain adjustment is applied to reduce noise artifacts, then noise performance is improved, but signal fidelity may be compromised
Solution Approach 1:
The patent implements dynamic gain adjustment where the gain applied to each microphone signal varies based on the detected structured noise content. The system continuously adapts gain parameters in response to changing noise conditions, reducing noise artifacts while preserving signal fidelity through real-time optimization.
Solution Approach 2:
The patent employs feedback mechanisms by detecting structured noise content in the processed signals and using this information to adjust gain parameters. The system monitors the output and modifies processing parameters accordingly, creating a closed-loop control system that reduces noise artifacts while maintaining signal fidelity.
Data Source
AI summary
In a system and method for maintaining the spatial stability of a sound field a balance gain may be calculated for two or more microphone signals. The balance gain may be associated with a spatial image in the sound field. Signal values may be calculated for each of the microphone. The signal values may be signal estimates or signal gains calculated to improve a characteristic of the microphone signals. The differences between the signal values associated with each microphone signal may be limited although some difference between signal values may be allowable. One or more microphone signals are adjusted responsive to the two or more balance gains and the signal gains to maintain the spatial stability of the sound field. The adjustments of one or more microphone signals may include mixing of two or more microphone. The signal gains are applied to the two or more microphone signals.