Far-Field Beamforming With Dynamic Acoustic Feedback Weighting
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Solution Overview
Problem
Acoustic feedback occurs in devices with acoustic sensors near transducers, particularly in size-constrained devices like glasses, leading to undesirable howls and reduced beamformer performance due to the proximity of microphones to loudspeakers, which existing methods either prevent effective placement or result in information loss.
Innovation Solution
An audio system with a controller that monitors feedback levels to adjust beamforming coefficients, using a subset of acoustic sensors that do not contribute to feedback and enhancing interaural characteristics to improve signal perception, while maintaining beamforming accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If acoustic sensors are placed near transducers in size-constrained devices, then device compactness is improved, but acoustic feedback occurs causing howls and reduced beamformer performance
Solution Approach 1:
The system detects acoustic feedback and converts this harmful phenomenon into useful information by using it to dynamically adjust beamforming coefficients. The feedback signal is analyzed to identify which acoustic sensors are contributing to feedback, and this information is then used to weight or exclude those sensors in the beamforming process, thereby eliminating the harmful effect while preserving device compactness
Solution Approach 2:
The beamforming coefficients are made dynamic rather than static. The system continuously monitors acoustic feedback levels and adjusts the beamforming weights in real-time based on the detected feedback conditions. This allows the system to adapt to changing acoustic environments and feedback conditions, maintaining optimal performance while preventing howls
2Object-affected harmful factors
If acoustic sensors near transducers are excluded from beamforming to prevent feedback, then acoustic feedback is reduced, but information loss occurs and beamformer performance decreases
Solution Approach 1:
Different beamforming coefficients are applied to different acoustic sensors based on their individual feedback characteristics. Instead of uniformly excluding all near-field sensors, the system analyzes each sensor's contribution to feedback and applies localized weighting - excluding or reducing weights for feedback-prone sensors while maintaining full utilization of feedback-free sensors, thereby preserving maximum information
Solution Approach 2:
The beamforming coefficients are dynamically adjusted based on detected feedback levels and characteristics. The system changes the parameters (weights) of the beamforming algorithm in real-time according to the acoustic feedback conditions, allowing optimal utilization of all sensors under different operating conditions
3Object-affected harmful factors
If beamforming coefficients are adjusted to prevent feedback, then acoustic feedback is minimized, but beamforming accuracy may be affected
Solution Approach 1:
The system implements a closed-loop feedback mechanism where acoustic feedback is continuously detected and used to adjust beamforming coefficients. This feedback loop allows the system to maintain beamforming accuracy by dynamically adapting to feedback conditions, ensuring that the beamforming process remains precise while preventing harmful howls
Data Source
AI summary
An audio system controls feedback when beamforming an output for production by transducers by generating a beamforming output signal based on audio from a first set and a second set of acoustic sensors. The first set may include acoustic sensors that may experience feedback from the transducers. The second set may exclude the acoustic sensors that cause feedback. The beamforming output from each set are combined as a weighted combination based on a beamforming coefficient that may be dynamically set to increase contribution of the first set until the combined output causes feedback, enabling the total beamforming output to benefit from a larger set of acoustic sensors while avoiding detrimental feedback. The interaural characteristics of the external environment may also be analyzed and the beamforming output modified to increase a difference in the interaural characteristic and thereby increase perception of the beamforming output.