Playback Device Noise Cancellation for External Audio
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Solution Overview
Problem
Existing playback devices with noise cancellation functions can only be used when playing content from the device itself, limiting their effectiveness in reducing ambient noise from external sources, such as during movies on airplanes or when ambient noise needs to be solely removed.
Innovation Solution
A playback device with components for acquiring external audio signals, generating noise cancellation signals, and switching between internal and external audio signals to synthesize noise reduction, allowing noise cancellation even for external audio inputs and enabling automatic playback control based on external signal presence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the noise cancellation function is incorporated in a playback device, then the structure becomes simplified compared to separate noise cancellation headphones, but the function is limited to only work when playing content from the device itself
Solution Approach 1:
The noise cancellation function is extended to work with both internal playback content and external audio signals. The switching portion enables the system to accept external audio inputs while the noise cancellation portion continuously generates noise cancellation signals, allowing the same hardware to serve multiple purposes: traditional playback with noise cancellation and external audio input with noise cancellation.
2Adaptability or versatility
If the switching portion switches between audio signal and external audio signal, then the adaptability is improved, but the device complexity increases
Solution Approach 1:
The switching portion merges the internal audio signal path and external audio signal path into a single unified output path that feeds into the synthesizing portion. This consolidation allows the noise cancellation signal to be integrated with whichever audio source is active, reducing the need for separate noise cancellation processing chains for each input type.
3Object-affected harmful factors
If the noise cancellation signal is generated based on collected noise, then the noise reduction effectiveness is improved, but important information in the noise may be masked
Solution Approach 1:
The system dynamically switches between different operating modes: when external audio is detected, the noise cancellation signal is synthesized with the external audio; when no external audio is present, the system can output only the noise cancellation signal. This dynamic adaptation allows the system to prioritize information preservation in external audio sources while maintaining noise reduction capability when appropriate.
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 for both internal and external audio sources, allowing users to control noise cancellation based on their needs, ensuring important information is not masked by the noise cancellation signal.
Implementation Method 1
a sound collecting device that collects ambient sound
Implementation Method 2
generates sound having a reverse phase to that of the ambient noise to remove or reduce the ambient noise
Implementation Method 3
a synthesizing portion that synthesizes the output signal from the switching portion with the noise cancellation signal
Data Source
AI summary
A playback device includes: a playback portion that plays back content and outputs at least an audio signal; an acquisition portion that acquires an external audio signal; a generating portion that, based on noise collected by a sound collecting device, generates a noise cancellation signal to reduce the noise; a switching portion that, if the acquisition portion has acquired the external audio signal when the playback portion is playing back content, switches an output signal from the audio signal to the external audio signal; and a synthesizing portion that synthesizes the output signal from the switching portion with the noise cancellation signal.