Dynamic Noise Suppressor Mode Switching for Remote Audio
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Solution Overview
Problem
Existing remote listening systems with two-channel noise suppressors effectively reduce ambient noise only when the remote microphone is close to the sound source, but attenuate desired sound when the distance increases, making it difficult for users to control the optimal positioning and leading to suboptimal noise suppression in noisy environments.
Innovation Solution
An automatic method that dynamically switches between two-channel and single-channel noise suppressor modes based on the relative strengths of the remote and local microphone signals, using a threshold to determine the appropriate mode and prevent sound attenuation, combined with an intelligibility enhancer that includes a spectral shaping filter and power normalizer to enhance speech clarity without additional gain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a two-channel noise suppressor is used to reduce ambient noise in a remote listening system, then noise reduction effectiveness is improved, but desired sound is attenuated when the distance between the remote microphone and sound source increases
Solution Approach 1:
The system dynamically switches between two-channel and single-channel noise suppressor modes based on the relative strengths of remote and local microphone signals. When the remote microphone signal strength exceeds the local microphone signal strength by a threshold amount, the system transitions to single-channel mode to prevent attenuation of desired sound, thereby adapting the noise suppression behavior to varying distance conditions between the remote microphone and sound source
Solution Approach 2:
The system changes the operational parameter of the noise suppressor from two-channel mode to single-channel mode based on signal strength comparison. This parameter change allows the system to maintain effective noise reduction when the remote microphone is close to the sound source while preventing unwanted attenuation when the distance increases
2Object-affected harmful factors
If the remote microphone is positioned closer to the sound source to improve noise suppression, then noise reduction effectiveness is improved, but user control and positioning flexibility are reduced
Solution Approach 1:
The noise suppression system automatically determines the optimal operating mode by comparing signal strengths from the remote and local microphones. The system self-adjusts between two-channel and single-channel modes without requiring user intervention or precise positioning knowledge, thereby maintaining effective noise reduction while preserving user positioning flexibility
3Ease of operation
If the distance between the remote microphone and sound source increases, then user positioning flexibility is improved, but noise suppression effectiveness deteriorates
Solution Approach 1:
The system dynamically adapts its noise suppression strategy based on real-time signal strength comparisons. When the remote microphone is far from the sound source, the system automatically switches to single-channel mode, which maintains noise suppression functionality without the attenuation problems that occur in two-channel mode at large distances, thereby preserving both positioning flexibility and noise suppression effectiveness
Data Source
AI summary
A remote microphone signal is obtained from a remote device, and a local microphone signal from a local device. A difference between strength of the remote microphone signal and strength of the local microphone signal is determined. An output audio signal is produced to drive a speaker in the local device. If the difference is greater than a threshold, then the local and remote microphone signals are applied to two input channels, respectively, of a two channel noise suppressor which produces the output audio signal, but if the difference is less than the threshold after a certain delay since the difference was greater than the threshold, then only the remote microphone signal is applied to a single input of a single channel noise suppressor which produces the output audio signal. Other aspects are also described and claimed.