Audio Output Device ANC Level Switching for Noise Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional audio output devices, such as headphones, fail to provide adequate noise cancellation when no audio signal is being played or the volume is low, leading to suboptimal noise reduction and potential distortion of sound quality due to excessive active noise cancellation (ANC) application.
Innovation Solution
An audio output device with a communication interface, signal detector, and control unit that determines the ANC level based on the connection state and presence of an audio signal, switching between first-level and second-level ANC modes to optimize noise cancellation without compromising sound quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If active noise cancellation is maximized to achieve better noise reduction, then noise cancellation effect is improved, but sound quality deteriorates due to frequency response distortion and audio artifacts
Solution Approach 1:
The patent applies dynamics by making the ANC level adjustable and switchable between multiple modes (first-level ANC and second-level ANC) based on operational conditions. The control unit dynamically selects the appropriate ANC level according to whether an audio signal is detected, allowing the system to adapt its noise cancellation strength to current usage scenarios rather than maintaining a fixed high level that degrades sound quality.
Solution Approach 2:
The patent changes the parameter of ANC level from a single fixed value to multiple discrete levels. By implementing first-level ANC and second-level ANC with different cancellation strengths, the system can adjust the degree of noise cancellation applied to the audio signal, thereby preventing excessive cancellation that would distort frequency response and degrade sound quality.
2Manufacturing precision
If first-level ANC is applied during audio playback, then sound quality is maintained, but noise reduction effect is insufficient when no audio is being played
Solution Approach 1:
The system dynamically adjusts ANC levels based on audio signal detection. When no audio signal is detected (such as when headphones are worn without connected playback devices or during pauses), the control unit switches to second-level ANC for maximum noise reduction. When audio playback is detected, it transitions to first-level ANC to maintain sound quality, thus optimizing performance for each operational state.
Solution Approach 2:
The control unit performs preliminary detection of audio signal presence and proactively switches between ANC levels before the user experiences either insufficient noise reduction or degraded sound quality. This preliminary action ensures the appropriate ANC level is already in place when the user needs it, whether for maximum noise blocking or for maintaining audio fidelity during playback.
3Object-affected harmful factors
If ANC level is increased to provide quieter environment, then noise cancellation is improved, but audio artifacts such as hissing noise are induced
Solution Approach 1:
The patent implements parameter changes by introducing multiple ANC levels with different strengths. The second-level ANC provides stronger noise cancellation when needed (no audio playback), while the first-level ANC provides milder cancellation during audio playback to avoid inducing audio artifacts like hissing noise. This parameter adjustment allows the system to optimize noise reduction without excessively increasing ANC strength that would generate harmful artifacts.
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 adjusts ANC levels to maximize noise reduction while maintaining sound quality, providing a quieter environment even when no audio is being played by switching to a stronger noise cancellation mode when no audio signal is detected.
Implementation Method 1
output an anti-noise (i.e. noise-canceling) signal having an opposite phase to that of the obtained noise. A mixture of the ambient noise and the anti-noise signal with the opposite phase of the noise is heard by a user, giving a resultant effect of cancelling the noise.
Data Source
AI summary
An audio output device controls the application of active noise cancellation (ANC) levels based on a current status of the device. The audio output device includes a communication interface configured to provide a wired or wireless connection to a playback device, a signal detector configured to detect an audio signal provided through the communication interface, an ANC module configured to apply a first-level ANC to the audio signal, and a control unit configured to determine a level of the ANC to be applied by the ANC module. Upon determining that the audio signal is not provided based on information provided from at least one of the communication interface or the signal detector, the control unit instructs the ANC module to perform a second-level ANC.