Laptop Speaker Vibration Detection for Chassis Rattle Control
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Solution Overview
Problem
Internal laptop speakers can rattle when lightly touching the chassis, causing objectionably distorted audio during video teleconferencing due to speaker-induced vibrations.
Innovation Solution
A method involving generating an audio signal, recording it with a microphone, normalizing and filtering the signal to extract a noise signal, determining correlation with the generated signal, and detecting speaker-induced vibration based on amplitude ratio thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the speaker is positioned close to the chassis to achieve compact design, then the device size is reduced, but speaker-induced vibration and rattling increase
Solution Approach 1:
The patent introduces a damping material as an intermediary layer between the speaker and the chassis. This mediator absorbs and dissipates the mechanical vibrations generated by the speaker, preventing them from being transmitted to the chassis and causing rattling sounds, while allowing the speaker to maintain its compact positioning.
Solution Approach 2:
The patent converts the harmful vibration energy into a beneficial form by using viscoelastic damping materials that transform mechanical vibration energy into heat through internal friction. The vibration that would cause rattling is instead dissipated as thermal energy, eliminating the harmful effect while maintaining the compact design.
2Ease of manufacture
If the speaker is lightly mounted to the chassis to ease assembly, then manufacturing complexity is reduced, but vibration and rattling occur
Solution Approach 1:
The damping material serves as a mediator that is applied to the speaker or chassis surface, providing vibration isolation without requiring complex mechanical mounting structures. This maintains assembly simplicity while eliminating rattling by absorbing vibrations at the source.
Solution Approach 2:
The patent changes the physical parameters of the interface between speaker and chassis by introducing a viscoelastic material with specific damping properties. This material parameter change enables effective vibration suppression while maintaining ease of assembly through simple material application rather than complex mechanical fastening.
3Object-generated harmful factors
If damping material is added to reduce vibration, then rattling is eliminated, but device complexity increases
Solution Approach 1:
The patent employs inexpensive damping materials such as viscoelastic polymers or foam that can be easily applied and do not require complex installation procedures. These materials provide effective vibration suppression while adding minimal structural complexity and can be replaced if necessary without affecting other system components.
Solution Approach 2:
The patent achieves vibration control by changing the material parameters at the speaker-chassis interface rather than modifying the overall device structure. This localized parameter change approach eliminates rattling while maintaining the simplicity of the overall device architecture.
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
Effectively identifies and notifies of speaker-induced vibrations, allowing for compensation measures such as servicing the system to mitigate undesirable rattling sounds.
Implementation Method 1
generating, based on the audio signal, an audio output at speakers of the information handling system
Implementation Method 2
recording, by a microphone of the information handling system and concurrently with generating the audio output at the speakers, the audio output of the speakers
Implementation Method 3
placing a damping material between the speaker and the chassis of the information handling system
Data Source
AI summary
Managing speaker-induced vibration of an information handling system, including generating, based on an audio signal, an audio output at speakers; recording, by a microphone and concurrently with generating the audio output at the speakers, the audio output of the speakers to define a recorded audio signal; normalizing the recorded audio signal to define a normalized recorded audio signal; filtering the normalized recorded audio signal to remove frequencies corresponding to the generated audio signal to define a filtered normalized recorded audio signal; extracting, based on the filtering, a noise signal from the filtered normalized recorded audio signal; determining that the noise signal is correlated with the generated audio signal; determining that a ratio of an amplitude of the noise signal to an amplitude of the normalized recorded audio signal is above a threshold; and detecting a speaker-induced vibration of the information handling system.