Segmented Acoustic Panels for Low-Frequency Sound in Compact Enclosures
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Solution Overview
Problem
As consumer electronics devices become smaller, they face challenges in producing high-quality low-frequency audio due to reduced internal space, leading to decreased sound quality and limited audible response.
Innovation Solution
A mechanically actuated panel acoustic system is implemented, where the device's enclosure is divided into sub-panels with different resonance frequencies, each driven by a digital signal processor to produce coherent acoustic outputs, effectively combining sound across a wide frequency band, including low frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the speaker size is decreased to fit smaller device enclosures, then the device compactness is improved, but the sound quality and loudness especially in low frequency range deteriorates
Solution Approach 1:
The patent divides the speaker system into multiple independent sub-speakers, each responsible for specific frequency bands. This segmentation allows the total surface area to be utilized effectively while maintaining low frequency performance, as each sub-speaker can be optimized for its designated frequency range without the limitations of a single small speaker.
Solution Approach 2:
The patent transitions from traditional volume-based speaker design to surface area-based panel utilization. By using the enclosure surfaces as radiating panels and dividing them into sub-panels, the system exploits the two-dimensional surface area rather than relying solely on three-dimensional speaker volume, thereby achieving better low frequency response in compact devices.
2Volume of stationary object
If the available open air volume within the device is reduced, then the device compactness is improved, but the air mass available for speaker vibration decreases, limiting the audible response
Solution Approach 1:
The patent segments the limited air volume into multiple sealed back cavities, each associated with a sub-panel. This allows the total surface area to be utilized for sound radiation while distributing the air mass requirements across multiple smaller volumes, maintaining adequate air spring compliance for low frequency response despite overall compactness.
3Device complexity
If a single speaker is used to cover wide frequency bands, then the device complexity is reduced, but the precision of frequency response especially in low frequency range deteriorates
Solution Approach 1:
The patent divides the frequency spectrum into multiple bands, with each sub-panel dedicated to specific bands. This segmentation enables precise control over frequency response characteristics, as each sub-panel can be independently optimized for its designated frequency range, achieving superior low frequency accuracy compared to a single full-range speaker.
Solution Approach 2:
Each sub-panel is designed with specific local characteristics (size, shape, boundary conditions) optimized for its assigned frequency bands. This local optimization allows each portion of the system to perform its specific function with high precision, particularly for low frequency response where traditional small speakers fail.
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 solution enhances sound quality by enabling the production of low-frequency audio with improved loudness and frequency range, addressing the limitations of smaller device enclosures while maintaining compactness.
Implementation Method 1
Each actuator and sub-panel combination may receive a separate audio signal. The actuator and its attached sub-panel convert an audio signal to acoustic output.
Implementation Method 2
The boundary conditions define a resonance frequency for each sub-panel. Different sub-panels are designed to have different resonance frequencies.
Implementation Method 3
The sum of the acoustic outputs of the sub-panels produces low frequency sound over a wide frequency band. The acoustic outputs of the sub-panels are coherent and can therefore be summed or combined constructively.
Data Source
AI summary
An electronic device includes an enclosure or housing panel that is used as part of an acoustic system. The panel is divided into several sub-panels. For each sub-panel, the device includes one or more actuators attached to vibrate the sub-panel. The actuator and its attached sub-panel convert an audio signal to acoustic output. Each actuator and sub-panel combination may receive a separate audio signal. The device includes a digital signal processor for controlling each of the sub-panel driving audio signals. The device may further include one or more backing frames that are attached to the panel to provide boundary conditions to the sub-panels. The boundary conditions define a resonance frequency for each sub-panel.