Headphone Noise Reduction Circuit With Vocal Monitoring Switch
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Solution Overview
Problem
Passive noise reduction headphones are inadequate in noisy environments due to their inability to effectively attenuate lower frequency components of ambient noise, leading to insufficient noise reduction and unclear vocal signals in conversations.
Innovation Solution
A noise reduction circuit with monitoring functionality that includes a microphone, an active noise reduction path, and a vocal signal compensation path, featuring a vocal clarity compensator with band pass filters and signal amplifiers to enhance vocal range frequencies, allowing for selective delivery of ambient signals for either noise reduction or vocal enhancement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If passive noise reduction with circumaural ear cushions is used, then higher frequency ambient noise is attenuated, but lower frequency components remain audible and vocal signals are unclear
Solution Approach 1:
The patent segments the audio signal processing into two distinct paths: an active noise reduction path for low-frequency noise cancellation and a vocal signal compensation path for restoring attenuated vocal frequencies. The switching device segments the signal flow, directing it to different processing paths based on the desired outcome (noise reduction vs. vocal clarity).
Solution Approach 2:
The system dynamically switches between two operational modes (noise reduction mode and vocal monitoring mode) based on user needs. The switching device enables dynamic selection between attenuating ambient noise and restoring vocal frequencies, making the system adaptable to different listening scenarios.
2Object-affected harmful factors
If active noise reduction is applied to cancel low frequency noise, then noise attenuation is improved, but vocal signals in the same frequency range are also attenuated
Solution Approach 1:
The patent creates separate signal processing paths: one dedicated to active noise reduction and another to vocal signal compensation. The segmentation allows independent optimization of each function without interfering with the other, resolving the conflict between noise cancellation and vocal clarity.
Solution Approach 2:
The switching device acts as an intermediary that selects which signal path to activate. When noise reduction is needed, it directs the signal to the active noise reduction path; when vocal clarity is needed, it directs the signal to the vocal compensation path, mediating between conflicting requirements.
3Adaptability or versatility
If a single path is used for signal processing, then device complexity is reduced, but the circuit cannot selectively provide both noise reduction and vocal clarity
Solution Approach 1:
The patent implements a multi-functional circuit that can perform both active noise reduction and vocal signal compensation through separate dedicated paths. The switching device enables the system to universally handle different signal processing requirements, making the headphone adaptable to various listening scenarios.
Solution Approach 2:
The system uses dynamic switching between two operational modes to provide versatility. The switching device enables real-time transition between noise reduction mode and vocal monitoring mode, allowing the circuit to adapt to different user needs without requiring multiple separate devices.
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 effectively cancels low-frequency noise components and restores attenuated vocal signals, providing improved audibility and clarity in noisy environments, enabling clearer conversations and robust noise reduction.
Implementation Method 1
a microphone configured to convert ambient sound into a corresponding electrical ambient signal
Implementation Method 2
an identical anti-noise waveform, which is equal in magnitude, but of opposite polarity is produced. Interaction of the noise waveform with the anti-noise waveform results in cancellation of the noise waveform
Implementation Method 3
The vocal clarity compensator may include a band pass filter and a signal amplifier coupled to the band pass filter's output
Implementation Method 4
The vocal clarity compensator may include a band pass filter and a signal amplifier coupled to the band pass filter's output
Data Source
AI summary
A noise reduction circuit 200 for a headphone 100 is disclosed herein. In a described embodiment, the headphone 100 includes a speaker driver 110 and the circuit 200 comprises a microphone 112 configured to convert ambient sound into a corresponding electrical ambient signal and which is disposed adjacent to the speaker driver's diaphragm. The circuit 200 further includes an active noise reduction path configured to provide active noise reduction of the ambient sound based on the corresponding electrical ambient signal and a vocal signal compensation path configured to restore attenuated signals within the vocal range of the corresponding electrical ambient signal to increase audibility of vocal signals of the ambient sound. The circuit 200 also includes a switching device 204,210 arranged to selectively deliver the corresponding electrical ambient signal to the active noise reduction path or to the vocal signal compensation path.