Audio Device Sidetone and Echo Control via Coupling Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Telephony devices struggle to determine the type of speaker being used for playback, leading to inappropriate processing of sidetone and multi-channel decorrelation, which can result in undesirable acoustic echo or reduced audio quality.
Innovation Solution
Measuring the coupling between microphones and speakers to control sidetone generation and multi-channel decorrelation, enabling or disabling these processes based on the coupling strength, without requiring the device to identify the type of speaker, and optionally using product information from connected audio playback devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sidetone is added to the receive signal, then the user perceives an active telephone connection, but acoustic echo occurs when external powered loudspeakers are used
Solution Approach 1:
The system dynamically changes the sidetone parameter (enabled/disabled) based on the detected speaker type. When external powered loudspeakers are detected, sidetone is disabled to prevent acoustic echo. When headsets or headphones are detected, sidetone is enabled to indicate active connection, thus adapting the parameter to the specific operating condition
Solution Approach 2:
The system uses feedback from the speaker detection mechanism to control sidetone generation. The detection of speaker type (external powered loudspeaker vs. headset/headphone) provides feedback that determines whether sidetone should be added to the receive signal, creating a closed-loop control system that prevents echo while maintaining connection indication
2Reliability
If multi-channel decorrelation is applied to the receive signal, then acoustic echo cancellation is improved, but audio quality deteriorates due to introduced distortion
Solution Approach 1:
The system dynamically changes the multi-channel decorrelation parameter (applied/not applied) based on the detected speaker type. When external powered loudspeakers are detected, decorrelation is applied to improve echo cancellation. When headsets or headphones are detected, decorrelation is disabled to preserve audio quality, thus adapting the parameter to the specific operating condition
Solution Approach 2:
The system applies different processing quality levels to different operating conditions. For external powered loudspeakers, aggressive decorrelation processing is applied locally to that channel to improve echo cancellation. For headsets/headphones, no decorrelation is applied to maintain high audio quality, thus making the processing quality local to the specific speaker type being used
3Reliability
If the telephony device processes the receive signal with sidetone and decorrelation, then connection indication and echo cancellation are improved, but processing resources are wasted when these processes are not beneficial
Solution Approach 1:
The system dynamically adjusts the receive signal processing based on the detected speaker type. When external powered loudspeakers are detected, both sidetone and decorrelation are applied. When headsets or headphones are detected, both processes are disabled, thus making the processing dynamic rather than static, and avoiding waste of processing resources on operations that are not beneficial for the current operating condition
Data Source
AI summary
Methods, systems, and apparatus for controlling audio signal processing are described herein. In accordance with certain embodiments, a measure of coupling between at least one microphone and one speaker associated with an audio device is obtained. The measure of coupling may be used to control audio signal processing, such as sidetone generation and application of multi-channel decorrelation to the audio signal.