Dipole Speaker Null-Zone Layout for Acoustic Feedback Suppression
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Solution Overview
Problem
Existing audio devices and teleconferencing systems face challenges with acoustic feedback, noise interference, and echo cancellation, particularly in environments with multiple connected devices, where sounds such as background noise, distractions, and echoes need to be controlled or suppressed.
Innovation Solution
The integration of dipole speakers with acoustically null sound areas and neural networks, where microphones are positioned within the null sound area, and neural networks are communicatively coupled to both the microphone and speaker, processing signals to enhance phase cancellation and noise reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional speakers and microphones are used in teleconferencing systems, then basic audio transmission is achieved, but acoustic feedback and noise interference occur
Solution Approach 1:
The patent utilizes the acoustic feedback signal itself as the reference input for the adaptive filter. By treating the harmful feedback signal as a useful reference, the system can identify and cancel the feedback path characteristics, converting the harmful effect into a beneficial reference for suppression.
Solution Approach 2:
The system implements an adaptive feedback cancellation mechanism where the output of the adaptive filter is subtracted from the microphone signal. This creates a closed-loop feedback system that continuously adjusts to cancel acoustic feedback while preserving the desired speech signal.
2Device complexity
If microphones are positioned close to speakers for compact design, then device size is reduced, but acoustic feedback increases
Solution Approach 1:
The adaptive filter acts as an intermediary processing element between the microphone and speaker signals. It mathematically models and cancels the acoustic feedback path, enabling compact physical positioning without the harmful feedback effects that would normally occur.
Solution Approach 2:
The patent replaces physical acoustic isolation mechanisms with a digital signal processing solution. Instead of using physical barriers or complex acoustic design to prevent feedback, the system uses adaptive filtering to electronically cancel the feedback path, enabling more compact designs.
3Adaptability or versatility
If multiple connected devices are used for teleconferencing, then communication versatility is improved, but network feedback and noise interference increase
Solution Approach 1:
The system implements adaptive feedback cancellation that works across networked devices by continuously monitoring and canceling feedback signals. The adaptive nature allows it to handle varying acoustic environments and network conditions while maintaining suppression effectiveness.
Solution Approach 2:
The feedback suppression mechanism is designed to work universally across different teleconferencing device configurations and network setups. The adaptive filter can handle various acoustic paths and feedback characteristics, making it applicable to single-device and multi-device scenarios alike.
4Measurement precision
If traditional noise suppression methods are used, then basic noise reduction is achieved, but speech-to-noise ratio remains insufficient
Solution Approach 1:
The adaptive filter continuously monitors the feedback signal and adjusts its coefficients to optimize noise suppression. This feedback-driven adaptation enables the system to maintain high speech-to-noise ratios by dynamically tracking and canceling both acoustic feedback and background noise.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This combination achieves an unprecedented speech-to-noise ratio of 75 dB or higher, significantly improving echo cancellation and noise suppression beyond traditional methods.
Implementation Method 1
Dipole speakers or transducers emit sound waves to the front and rear. These front and rear sound waves are substantially out of phase. Thus, dipole speakers create a null zone, acoustically null sound plane, acoustically null sound area, acoustic cancellation zone, and/or acoustic cancellation area where the acoustic waves from the front of the dipole speaker meet and cancel or quasi-cancel the acoustic waves from the rear of the dipole speaker.
Data Source
AI summary
Devices, methods, and systems are described for an anti-feedback audio device (100) comprising a dipole speaker (110) having an acoustically null sound plane (115) or acoustically null sound area (117), a first microphone (120) disposed substantially within the acoustically null sound plane (115) or acoustically null sound area (117), and a neural network (130) communicatively coupled to the dipole speaker and the first microphone (120) such that a first output from the first microphone is communicated to the neural network (130) for processing, and a second output from the neural network (130) is communicated to the dipole speaker (110). The combination of the dipole phase cancellation and the neural network gives an unexpected result of an extremely high signal-to-noise ratio for speech over noise.