Vented Speaker Assembly With Acoustic Channel Phase Control
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Solution Overview
Problem
Existing loudspeaker designs struggle to maintain acoustic radiation efficiency at low frequencies without compromising performance in mid and high frequency ranges, particularly when located outside a vehicle enclosure, often resulting in out-of-phase acoustic output between the vehicle interior and exterior.
Innovation Solution
The use of a pressure vessel with active and passive acoustic radiators, along with acoustic channels and filters, to create in-phase acoustic emissions that are radiated into both the vehicle interior and exterior, while incorporating features like semi-permeable membranes and air pathways to prevent water ingress and optimize frequency response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a loudspeaker is placed outside a vehicle enclosure to improve low-frequency acoustic radiation efficiency, then low-frequency performance is enhanced, but the acoustic output becomes out of phase between vehicle interior and exterior
Solution Approach 1:
The system divides the acoustic radiation function into two separate paths: one for the vehicle exterior and one for the vehicle interior. The active acoustic radiator outside the vehicle radiates sound in one direction while the acoustic channel directs sound into the vehicle interior, allowing independent optimization of each path's acoustic characteristics and phase relationship
Solution Approach 2:
The acoustic channel acts as an intermediary element that transfers acoustic energy from the exterior location to the interior space. This mediator enables the exterior loudspeaker to produce in-phase acoustic output inside the vehicle by providing a controlled acoustic pathway that maintains phase coherence
2Power
If the active acoustic radiator is exposed to the external environment to radiate sound, then acoustic output is achieved, but water and moisture can ingress and damage the magnetic circuit
Solution Approach 1:
A semi-permeable membrane is used to seal the acoustic channel, allowing acoustic energy to pass through while preventing water and moisture ingress. This flexible film structure enables the system to maintain protection against environmental elements while preserving acoustic radiation capability
Solution Approach 2:
The semi-permeable membrane serves as an intermediary barrier between the external environment and the protected components. It selectively permits acoustic energy transmission while blocking harmful water and moisture, thus protecting the magnetic circuit and other sensitive components
3Ease of operation
If acoustic emissions are directed into the vehicle interior through an acoustic channel, then in-phase acoustic output is achieved, but acoustic energy is lost to the exterior environment
Solution Approach 1:
The acoustic energy distribution is segmented into two functional paths: one optimized for interior radiation through the acoustic channel and another for exterior radiation. This segmentation allows the system to achieve in-phase interior output while simultaneously maintaining effective exterior sound radiation, minimizing overall energy loss
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 configuration enhances acoustic output efficiency across various frequencies, ensuring in-phase audio transmission within the vehicle and to the exterior, while maintaining acoustic integrity and preventing moisture ingress.
Implementation Method 1
The active acoustic radiator normally comprises a magnetic circuit and a moveable diaphragm
Implementation Method 2
The acoustic channel can radiate acoustic emissions into the interior of the vehicle enclosure that are in-phase with the acoustic emissions generated by the active acoustic radiator
Implementation Method 3
The vent can connect the interior of the pressure vessel to the environment outside both the pressure vessel and the vehicle enclosure
Data Source
AI summary
A loudspeaker system may include a pressure vessel, an active acoustic radiator, an acoustic channel, and a vent. The pressure vessel can be disposed outside a vehicle enclosure. The pressure vessel can be configured to maintain a controlled environment different from an environment outside both the pressure vessel and the vehicle enclosure. The active acoustic radiator can be disposed within the pressure vessel and may radiate acoustic emissions outside the vehicle enclosure. The active acoustic radiator comprising magnetic circuit, a moveable diaphragm, and a voice coil. The acoustic channel can fluidly connect an interior of the pressure vessel with an interior of the vehicle enclosure. The acoustic channel can radiate acoustic emissions into the interior of the vehicle enclosure that are substantially in-phase with the acoustic emissions generated outside the vehicle by the active acoustic radiator within a range of operating frequencies. The vent can connect the interior of the pressure vessel to the environment outside both the pressure vessel and the vehicle enclosure. The resulting system provides efficient sound generation both inside and outside of a vehicle interior, without the efficiency or sound fidelity compromises of prior systems.