Gas-Filled Speaker Volume with Flexible Membrane
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Solution Overview
Problem
In speaker systems, especially in mobile devices, the back pressure from air within sealed enclosures retards the diaphragm's movement, degrading sound quality, and abrupt changes in barometric pressure can cause the diaphragm to 'stick' due to pressure imbalances, which is not effectively addressed by vent holes in gas-filled enclosures.
Innovation Solution
A speaker system with a gas-filled cavity and an air cavity separated by an interior partition with a flexible membrane, where the air cavity has a vent hole for pressure equalization, allowing the gas to expand or contract without significantly affecting the diaphragm, thus maintaining sound quality across varying barometric pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the speaker enclosure is filled with less dense gas (helium or hydrogen) to reduce back pressure and improve sound quality, then the diaphragm movement is less retarded and sound quality improves, but the enclosure becomes sensitive to barometric pressure changes causing the diaphragm to stick
Solution Approach 1:
The speaker enclosure is divided into two separate cavities: a gas-filled cavity that provides acoustic compliance and a vented air cavity that handles barometric pressure equalization. This segmentation allows each cavity to serve its specific function without interfering with the other, resolving the contradiction between reducing back pressure and preventing diaphragm sticking.
Solution Approach 2:
A flexible membrane acts as an intermediary between the gas-filled cavity and the vented air cavity. The membrane allows pressure equalization while maintaining the separation between the two gas types, enabling the system to handle barometric pressure changes without exposing the diaphragm to significant pressure imbalances.
2Reliability
If a vent hole is added to the enclosure to allow barometric pressure equalization and prevent diaphragm sticking, then pressure equalization is achieved quickly, but sound quality degrades due to the vent hole
Solution Approach 1:
The vent hole is placed only in the air cavity, not in the gas-filled cavity. This segmentation ensures that the vent hole serves its pressure equalization function without directly affecting the acoustic properties of the gas-filled cavity, thereby preventing sound quality degradation while maintaining reliable pressure equalization.
Solution Approach 2:
The flexible membrane serves as an intermediary that isolates the gas-filled cavity from the vent hole. This allows the vent hole to equalize barometric pressure in the air cavity without allowing the less dense gas to escape or directly interact with the vent, preserving sound quality while achieving pressure equalization.
3Object-generated harmful factors
If the speaker enclosure volume is increased to improve sound reproduction, then sound quality improves, but the device size increases which is problematic for mobile devices
Solution Approach 1:
The system changes the physical parameter of gas density by using less dense gases (helium or hydrogen) in the gas-filled cavity. This parameter change increases the effective acoustic compliance of the enclosure, improving sound reproduction quality without requiring a larger physical enclosure volume, thus resolving the contradiction for mobile device applications.
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
This design effectively enlarges the speaker enclosure volume using less dense gases like helium or hydrogen, minimizing pressure changes on the diaphragm and preventing sound degradation due to barometric fluctuations, ensuring consistent sound production.
Implementation Method 1
As the air pressure surrounding the speaker enclosure decreases, the gas inside the enclosure will be allowed to expand. Similarly, when the air pressure surrounding the speaker enclosure increases, the gas within the enclosure will be allowed to contract.
Implementation Method 2
The enclosure surrounding the air cavity has a vent hole to allow the surrounding air to travel into and out of the air cavity.
Data Source
AI summary
A speaker enclosure includes a gas cavity and an air cavity separated by a flexible membrane. A diaphragm is located roughly in an opening of the enclosure surrounding the gas cavity and attached to the enclosure by an outer suspension member. The enclosure, the flexible membrane, the diaphragm, and the outer suspension member are gas and air impermeable. The enclosure surrounding the air cavity has a vent hole to allow air to travel into and out of the air cavity for barometric pressure equalization of the gas cavity. Other embodiments are also described and claimed.