Directional Hearing Protection for Siren Noise and Spatial Speech
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Solution Overview
Problem
Existing hearing protection devices either block all sounds, including wanted sounds like speech, or struggle to effectively reduce varying noises like sirens, and often require power for active noise cancellation.
Innovation Solution
A hearing protection device with a speaker, microphone, and UWB radio that uses 3D spatial audio encoding and predefined siren frequencies to selectively reduce unwanted noises while allowing desired sounds to be localized, using passive and active noise cancellation techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If passive noise protection is used to block all sounds, then noise reduction is improved, but wanted sounds such as speech are also blocked
Solution Approach 1:
The hearing protection device applies different noise reduction characteristics to different frequency ranges and sound sources. Speech frequencies are preserved while harmful noise frequencies are attenuated, creating localized quality differences in the audio spectrum to resolve the contradiction between noise blocking and speech preservation
Solution Approach 2:
The device dynamically adjusts noise reduction parameters based on the detected sound environment. By changing attenuation levels across different frequency bands in real-time, the system maintains noise protection while allowing wanted sounds to pass through, resolving the binary choice between complete blocking and complete openness
2Object-affected harmful factors
If active noise cancellation is used to reduce varying noises, then noise reduction effectiveness is improved, but power consumption increases and it is less effective for non-constant noises
Solution Approach 1:
The hearing protection device uses periodic sampling of the acoustic environment to identify varying noise patterns. By detecting periodic characteristics of sounds like sirens and speech, the system applies targeted noise reduction only when needed, reducing power consumption while maintaining effectiveness for non-constant noises
Solution Approach 2:
The system dynamically adapts its noise cancellation strategy based on real-time detection of noise characteristics. It switches between active cancellation for constant noises and selective attenuation for varying noises, optimizing both effectiveness and power usage through dynamic parameter adjustment
3Loss of information
If 3D spatial audio encoding is applied to preserve directional information, then situational awareness is improved, but device complexity increases
Solution Approach 1:
The hearing protection device divides the audio processing into separate channels for different spatial directions. By segmenting the audio spectrum into directional components, the system preserves spatial information through relatively simple per-channel processing rather than complex full-spectrum analysis, reducing overall device complexity
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
Enables effective noise reduction of specific sounds like sirens while preserving communication and situational awareness, even without continuous power, by using UWB localization and 3D audio encoding.
Implementation Method 1
determining a relative location of the second device for hearing protection from the received transmissions
Implementation Method 2
playing the 3D spatial audio encoded audio signal through the speaker
Implementation Method 3
at least one microphone
Implementation Method 4
Active noise cancelling devices reduce the loudness of sounds heard by a wearer by essentially playing a 180° out of phase sound to the sound being cancelled
Data Source
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AI summary
Hearing protection (102) including passive noise cancellation or reduction material can include ultrawideband radios (110). The hearing protection may include a microphone (112a, 112b) for capturing the audio (106) when the user (104) is speaking. An ultrawideband radio (110) can be used to transmit the audio (106) to other users (104) with similar hearing protection (102). The ultrawideband radio (110) can also be used to determine a relative location of other users (104) and 3D spatial audio encoding can be applied to the associated audio signals in order to make it appear that the audio signals are coming from the relative location of the other respective users (104). The hearing protection (102) may be used in a wide range of environments, including for example for first responders. In such cases, the hearing protection (102) may include active noise cancelling functionality for reducing a loudness of siren noises.