Arrayed Speakers for Uniform Driver Field Noise Cancellation
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Solution Overview
Problem
Conventional noise cancellation systems fail to effectively cancel noise over a large spatial region around the head of an occupant due to a mismatch between the noise field and the driver field, leading to inefficient noise cancellation and potential audible artifacts during certain noise-related events.
Innovation Solution
The implementation of an active noise cancellation system using arrayed speakers that produce a substantially uniform sound pressure field matching the noise field in magnitude but with inverted phase over a larger spatial region, transitioning to an in-phase configuration during high-noise events to prevent amplifier clipping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If conventional noise cancellation systems use a single speaker or non-arrayed speakers, then the system structure is simple, but the noise cancellation area around the head is limited and the driver field does not match the noise field
Solution Approach 1:
The system divides the speaker into multiple independent elements arranged in an array configuration. Each speaker element operates independently with controlled phase and amplitude, allowing the collective array to produce a uniform driver field that matches the spatial characteristics of the noise field, thereby expanding the noise cancellation area around the occupant's head.
Solution Approach 2:
The patent applies different phase relationships to different regions of the speaker array. By controlling the phase of individual speaker elements, the system creates a uniform driver field in the region around the occupant's head, matching the local characteristics of the noise field in that specific spatial region.
2Area of stationary object
If the speaker array operates in arrayed configuration to produce uniform sound pressure field, then noise cancellation area increases, but amplifier clipping occurs during high-noise events
Solution Approach 1:
The system dynamically switches between two operational configurations: arrayed configuration for normal noise conditions to maximize cancellation area, and in-phase configuration for high-noise events to prevent amplifier clipping. This dynamic adaptation allows the system to maintain reliability across varying noise conditions while preserving the benefit of expanded cancellation area when appropriate.
Solution Approach 2:
The patent changes the phase relationship parameter between speaker elements based on noise conditions. During high-noise events, the system transitions from arrayed phase relationships to in-phase relationships, effectively changing the operational parameters to prevent amplifier clipping while maintaining adequate noise cancellation performance.
3Reliability
If the system transitions to in-phase configuration during high-noise events, then amplifier clipping is prevented, but noise cancellation effectiveness is reduced
Solution Approach 1:
The system periodically monitors noise levels and switches between configurations based on detected conditions. During high-noise events, it temporarily operates in in-phase mode to prevent clipping, then returns to arrayed mode for optimal cancellation effectiveness, creating a periodic switching pattern that balances reliability and productivity.
Solution Approach 2:
The system accepts partial degradation of noise cancellation effectiveness during high-noise events by switching to in-phase configuration, prioritizing amplifier reliability. This partial action approach ensures the system remains operational and can resume full effectiveness when noise conditions return to normal.
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 approach significantly increases the area of noise cancellation around the head, providing more effective noise reduction while avoiding audible artifacts by efficiently managing speaker output during noise-related events.
Implementation Method 1
produce a substantially uniform sound pressure field matching the noise field in magnitude but with inverted phase
Implementation Method 2
Each active noise cancellation zone includes at least one system microphone and a plurality of speakers
Data Source
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AI summary
A method and system for a noise cancellation comprises an amplifier in communication with the three or more speakers disposed in an area. A system controller produces a driver signal for each of the speakers in response to a signal from at least one microphone detecting sound in the area and communicates the driver signals to the amplifier. The amplifier drives each speaker with the driver signal produced for that speaker. In response to the driver signals, the speakers emit sound that combined produces a substantially uniform sound pressure field for a particular zone within the area. The substantially uniform sound pressure field produced by the speakers has a magnitude and phase adapted to attenuate a noise field in the area corresponding to the sound detected by the at least one microphone.