Helmet ANC Mounting Plate for Acoustic Coupling and Easy Integration
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Solution Overview
Problem
Existing helmets with active noise cancellation systems face challenges in integration during manufacturing, require structural modifications, and struggle with acoustic coupling and feedback issues, making it difficult to effectively attenuate wind noise while preserving useful sound information.
Innovation Solution
A mounting plate with a loudspeaker and reference microphone integrated into the helmet's design forms an acoustic chamber, minimizing feedback and simplifying installation by using a contoured shape and apertures for optimal acoustic coupling, allowing for easy integration or retrofitting without structural changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If passive sound insulating material is added to reduce wind noise, then noise attenuation is improved, but helmet weight and size increase
Solution Approach 1:
The patent replaces passive mechanical sound insulation materials with an active noise cancellation system that uses electronic signal processing. The system employs microphones to detect wind noise, processes the signals through a controller, and generates anti-noise signals via speakers to actively cancel unwanted sounds, thereby eliminating the need for heavy passive insulation materials.
Solution Approach 2:
The patent changes the approach from static passive insulation to dynamic active noise cancellation. By using microphones and electronic signal processing, the system adapts to varying wind noise conditions in real-time, adjusting the cancellation signals dynamically rather than relying on fixed physical barriers that would require increased mass for better attenuation.
2Object-affected harmful factors
If passive sound insulating material is added to reduce wind noise, then noise attenuation is improved, but useful sound information in mid- to high frequencies is attenuated
Solution Approach 1:
The patent applies frequency-selective noise cancellation by targeting specific frequency bands. The system uses microphones and signal processing to identify and cancel low-frequency wind noise while preserving mid- to high-frequency sounds. The controller processes signals differently for different frequency ranges, applying aggressive cancellation only where needed and maintaining transparency for useful auditory information.
Solution Approach 2:
The system dynamically adjusts its noise cancellation parameters based on frequency content. By analyzing the spectral characteristics of incoming sounds, the controller modifies the cancellation signals to selectively attenuate unwanted low-frequency wind noise while maintaining pass-through for important higher-frequency sounds, thus preventing information loss.
3Ease of manufacture
If a mounting plate is added to simplify ANC system integration, then ease of manufacture is improved, but device complexity increases
Solution Approach 1:
The mounting plate is designed as a multi-functional component that serves multiple purposes: it provides a standardized interface for attaching ANC system components, maintains the structural integrity of the helmet, and facilitates easy installation and removal. This universal plate design simplifies the integration process by consolidating multiple functions into a single standardized element.
Solution Approach 2:
The patent divides the ANC system integration into modular components that can be independently attached to the mounting plate. This segmentation allows the ANC system to be separated from the helmet structure, enabling easy installation and removal without permanent modifications to the helmet itself, thus simplifying the overall integration process.
4Reliability
If acoustic coupling is improved for ANC system performance, then noise cancellation effectiveness is improved, but feedback from loudspeaker to microphone increases
Solution Approach 1:
The mounting plate acts as an acoustic intermediary that manages the relationship between the loudspeaker and microphone. It provides controlled acoustic coupling to ensure effective noise cancellation while incorporating features to minimize unwanted feedback paths. The plate's structural design and positioning create optimal acoustic conditions for signal transmission while preventing direct feedback loops.
Solution Approach 2:
The system uses feedback mechanisms where the microphone detects the acoustic environment and the controller adjusts the cancellation signals accordingly. By continuously monitoring the acoustic feedback and adapting the cancellation signals in real-time, the system maintains effective noise cancellation while minimizing harmful feedback effects through active signal adjustment.
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
The solution provides effective noise cancellation in desired frequency ranges by reducing unwanted noise while maintaining the ability to hear important sound information, with improved acoustic coupling and simplified installation processes.
Implementation Method 1
a sound is attenuated through use of a noise-cancellation speaker that emits a sound wave with the same amplitude but with opposite phase (also known as 'antiphase', 'antinoise' or 'antisound') to the original sound. The original sound wave and the sound wave from the noise cancellation speaker destructively interfere with one another to effectively cancel each other out.
Implementation Method 2
at least one reference microphone mounted on a second face of the plate for measuring the sound pressure level
Data Source
AI summary
An active noise cancellation (ANC) system has a mounting plate, a first face of which is configured to be disposed against an inner surface of a helmet to form, with the helmet, a chamber. When the mounting plate is mounted on the helmet, a loudspeaker provided on the first face of the mounting plate is within the chamber. The plate has an aperture for allowing transmission of sound from the loudspeaker to the spatial region. At least one reference microphone is mounted on a second face of the plate. The plate acts as a mounting plate for components of the ANC system, simplifying the process of installing an ANC system. Also, the plate serves to define a chamber that accommodates the loudspeaker of the ANC system and provides good acoustic coupling of the sound signal from the loudspeaker of the ANC system into the quiet zone of the ANC system.