Speaker Back Cavity Dividing Structures for Acoustic Mode Control
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Solution Overview
Problem
Portable electronic devices face challenges in designing a back cavity for integrated hands-free loudspeakers due to space constraints, leading to elongated shapes that cause artifacts in frequency response, reducing sound quality and increasing the risk of physical failure.
Innovation Solution
A compact back cavity design with dividing structures, such as walls with apertures or a tuned pipe, is implemented to separate the cavity into adjacent air mass holding sections, attenuating and shifting modes to improve frequency response and reduce the risk of physical failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the back cavity is made compact to fit space constraints, then the device size is reduced, but the cavity shape becomes elongated causing artifacts in frequency response
Solution Approach 1:
The back cavity is divided into multiple separate air mass holding sections using dividing walls with apertures or tuned pipes. This segmentation prevents the formation of unwanted higher modes while maintaining a compact overall cavity volume, resolving the contradiction between compact size and favorable shape characteristics.
2Volume of moving object
If the back cavity is made compact, then space constraints are satisfied, but the risk of physical failure increases
Solution Approach 1:
By segmenting the cavity into separate air mass holding sections, the patent reduces the risk of physical failure. The segmentation prevents excessive pressure buildup and distributes mechanical stresses more evenly across the speaker structure, thereby improving reliability while maintaining compact dimensions.
3Shape
If dividing structures are added to the back cavity, then frequency response is improved, but device complexity increases
Solution Approach 1:
The dividing structures are implemented as thin walls with apertures or integrated tuned pipes, which add minimal structural complexity while effectively controlling the acoustic modes. These thin-film-like dividers provide the necessary acoustic separation without significantly increasing device complexity.
4Volume of moving object
If the back cavity is elongated to provide sufficient volume, then acoustic performance is maintained, but space constraints are violated
Solution Approach 1:
Instead of increasing cavity length in one dimension, the patent uses dividing walls to create multiple air mass holding sections that provide sufficient acoustic volume within a compact three-dimensional footprint. This dimensional reorganization allows adequate volume without elongation.
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 design achieves a flattened frequency response, enhanced sound quality, and reduced likelihood of premature speaker failure by eliminating higher modes and allowing for a more compact cavity shape without elongated parts.
Implementation Method 1
A compact back cavity design with dividing structures, such as walls with apertures or a tuned pipe, is implemented to separate the cavity into adjacent air mass holding sections, attenuating and shifting modes to improve frequency response
Implementation Method 2
The dividing structure comprises apertures to limit travel of pressure waves through the at least one aperture between the sections
Data Source
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AI summary
An apparatus including a sound transducer; and a housing having the sound transducer connected thereto. The housing forms a substantially sealed air space back cavity acoustically coupled to the sound transducer. The housing includes a housing member having a first dividing structure located in the back cavity to connect two adjacent air mass sections of the back cavity, where the dividing structure includes at least one aperture to permit travel of sound waves through the at least one aperture between the air mass sections.