Impulse Pressure Rejecting Valve for Speaker Back-Volume Control
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Solution Overview
Problem
Portable communication devices face challenges in maintaining optimal speaker performance due to their compact size, which restricts the speaker's back volume chamber, leading to reduced low-frequency sound output and potential distortion from external pressure changes, such as user interaction.
Innovation Solution
An impulse pressure rejecting valve is introduced between the speaker's back volume chamber and the system enclosure, featuring a pressure-sensitive membrane with an aperiodic vent containing a flow resistive mesh. This valve closes during impulse pressure events to prevent distortion and opens for pressure equalization, effectively increasing the acoustic size of the back volume chamber and maintaining continuous low-frequency output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the back volume chamber is made physically larger to improve low-frequency sound output, then low-frequency output is improved, but the device enclosure volume increases
Solution Approach 1:
The patent uses the system enclosure volume to acoustically augment the speaker back volume chamber. The valve couples the back volume chamber to the system enclosure, allowing the larger system volume to function as an acoustic extension of the smaller back volume chamber, thereby achieving enhanced low-frequency output without increasing the physical back volume chamber dimensions.
Solution Approach 2:
The patent introduces a valve as an intermediary component between the back volume chamber and the system enclosure. This valve selectively controls the acoustic coupling, allowing the system enclosure to serve as an extended back volume chamber when needed, while maintaining isolation when pressure stability is required.
2Power
If the back volume chamber is acoustically coupled to the system enclosure to increase acoustic volume, then low-frequency output is improved, but pressure changes from user interaction cause speaker distortion
Solution Approach 1:
The patent employs a dynamic valve that automatically opens or closes based on pressure differential conditions. When user interaction causes pressure changes in the system enclosure, the valve closes to isolate the back volume chamber and prevent speaker distortion. When no pressure changes occur, the valve remains open to provide acoustic coupling for enhanced low-frequency output.
Solution Approach 2:
The patent extracts the harmful pressure fluctuations from the coupled acoustic system by using the valve to isolate the back volume chamber from system enclosure pressure changes. This allows the beneficial acoustic coupling to be maintained while removing the detrimental pressure transmission that would cause speaker distortion.
3Object-affected harmful factors
If the valve remains closed to prevent pressure transmission, then speaker distortion is prevented, but low-frequency sound output is reduced
Solution Approach 1:
The patent uses a dynamic valve that automatically transitions between open and closed states based on pressure differential conditions. This allows the system to achieve both low-frequency enhancement (when open) and distortion prevention (when closed) by adapting to real-time pressure conditions in the system enclosure.
Solution Approach 2:
The patent changes the operational state of the valve (open/closed) based on pressure differential parameters. When the pressure differential exceeds a threshold indicating user interaction, the valve closes to prevent distortion. When pressure conditions are stable, the valve opens to maximize low-frequency output, thus adapting system behavior to operational conditions.
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 enhances low-frequency sound output and reduces the required enclosure volume while preventing distortion caused by external pressure changes, ensuring more stable and continuous audio performance.
Implementation Method 1
An aperiodic vent including a flow resistive mesh may be formed in the valve membrane or diaphragm to allow communication between the two volumes. By allowing communication between the two volumes and controlling the flow resistance using the flow resistive mesh, the back volume chamber can be made to behave acoustically larger than it is in physical dimension.
Implementation Method 2
The valve is therefore pressure sensitive and closes in response to the pressure event caused by the user interaction to prevent the pressure event from impacting the speaker.
Implementation Method 3
Once the pressure event is gone and/or the pressure equalizes (e.g., via the aperiodic vent and/or a barometric vent in the system volume) the valve opens to allow communication between the back volume chamber and the system volume.
Data Source
AI summary
A portable electronic device comprising: an enclosure having an enclosure wall that forms an interior chamber and a sound output port to an ambient environment; a speaker positioned within the interior chamber, the speaker having a front volume chamber coupling a sound output surface of the speaker to the sound output port and a back volume chamber acoustically coupled to the interior chamber by an aperiodic vent; and a valve operable to open and close the aperiodic vent in response to a pressure change.