Tapered Speaker Surround for Pressure Equalization
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Solution Overview
Problem
Integrating a speaker in a small form factor electronic device is challenging due to the need for a substantial back volume of air, which increases the component size, and water-resistant designs that impede air movement, causing pressure differentials that affect the speaker's operation.
Innovation Solution
A speaker assembly with a tapered speaker surround that limits diaphragm displacement while maintaining frequency response, and routing electrical connectors atop the speaker assembly or within the housing to maximize diaphragm size, along with optimized venting and partitioning to manage pressure changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the back volume of the speaker is opened to the interior volume of the device to utilize available space, then the speaker performance is improved, but pressure changes within the device adversely affect the speaker operation
Solution Approach 1:
A compliant seal is introduced as an intermediary element between the speaker back volume and the device interior volume. This seal allows controlled air movement to equalize pressure while preventing direct communication that would allow uncontrolled pressure differentials to affect speaker operation. The compliant material enables the seal to deform and maintain sealing while accommodating pressure changes.
Solution Approach 2:
The compliant seal is implemented as a flexible thin film or membrane that separates the speaker back volume from the device interior. This flexible barrier allows for pressure equalization through controlled deformation while maintaining separation to prevent harmful pressure differentials from directly impacting speaker operation.
2Reliability
If a substantial back volume of air is provided for the speaker to improve audio playback, then the speaker performance is improved, but the component size increases making integration challenging
Solution Approach 1:
The speaker back volume is merged with the device interior volume by opening the speaker rear to the device interior through a compliant seal. This combines the speaker's required back volume with the already-existing device interior space, eliminating the need for dedicated speaker housing volume and enabling integration into compact devices while maintaining audio playback performance.
3Reliability
If water seals are implemented to make the device water-resistant, then the device water resistance is improved, but air movement into and out of the device is impeded causing pressure changes
Solution Approach 1:
The compliant seal is applied locally at the speaker assembly interface where pressure equalization is needed, while water seals are maintained at other locations for water resistance. This localized approach allows air movement specifically at the speaker back volume interface to equalize pressure without compromising the overall water-resistant design of the device.
Solution Approach 2:
The compliant seal changes the pressure equalization parameter by allowing controlled air flow between the speaker back volume and device interior. This parameter change enables pressure equalization that counteracts the pressure differentials created by water seals impeding air movement, thereby resolving the harmful effects on speaker operation.
Data Source
AI summary
This disclosure describes a speaker assembly suitable for use in a portable electronic device utilizing water resistant ports. The speaker assembly can have an open back that subjects a back volume of the speaker to pressure differentials within a device housing of the portable electronic device. The speaker assembly can utilize a speaker surround having a varying thickness. The varying thickness speaker surround allows the speaker to maintain an acceptable frequency response profile while limiting the travel of the diaphragm it is coupled with. The disclosure also describes how electrically conductive pathways can be integrated within a housing of the speaker assembly.