Remote Audio Gain Estimation to Prevent Acoustic Howling
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Solution Overview
Problem
Existing acoustic systems face challenges in preventing howling, an unwanted feedback effect, as they typically address it after it occurs rather than anticipating and preventing it.
Innovation Solution
The method involves calculating the overall system gain by combining transmitter and receiver gain information, allowing for selective system gain reduction before howling occurs, which includes determining local gain for each frequency and applying noise attenuation factors to prevent system gain from exceeding a threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If system gain is increased to improve audio transmission quality, then audio quality is improved, but howling occurs due to excessive feedback
Solution Approach 1:
The system performs preliminary detection of system gain levels and identifies potential howling conditions before they occur. By monitoring the system gain and comparing it against predetermined thresholds, the system takes preventive action by reducing gain or activating noise attenuation before howling actually occurs, rather than reacting after the problem has manifested
Solution Approach 2:
The system continuously monitors the acoustic feedback path and measures the system gain by analyzing the relationship between transmitted and received signals. This feedback mechanism allows the system to detect changes in system gain in real-time and adjust parameters dynamically to prevent howling while maintaining optimal audio quality
2Reliability
If noise attenuation is applied to prevent howling, then howling is prevented, but noise in the audio signal increases
Solution Approach 1:
The system applies noise attenuation selectively in the frequency domain rather than uniformly across all frequencies. By identifying specific frequency bands where system gain exceeds thresholds and applying attenuation only to those bands, the system prevents howling in problematic frequencies while preserving audio quality in frequencies where attenuation is not needed
Solution Approach 2:
The system dynamically adjusts noise attenuation parameters based on the measured system gain characteristics. When system gain is low, minimal or no attenuation is applied. When system gain approaches problematic levels, attenuation parameters are adjusted incrementally to prevent howling while minimizing impact on overall audio quality
Data Source
AI summary
A method of processing an audio signal transmitted from a remote transmitter and received at a local receiver of an acoustic system, includes at the receiver receiving with the audio signal an indication of remote transmitter gain, determining an overall system gain of the acoustic system from the remote transmitter gain and a local receiver gain and selectively applying a system gain reduction step to the audio signal if it is determined that the overall system gain exceeds a threshold.