Nested Helmholtz Resonators for Speaker Frequency Control
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Solution Overview
Problem
Compact electronic devices face challenges in achieving high-quality audio due to spatial integration constraints, liquid resistance, and frequency response issues, particularly in portable and wearable devices where extended sound paths lead to undesired frequency peaks and roll-offs.
Innovation Solution
Incorporating multiple Helmholtz resonators with independent frequency responses, spatially nested and acoustically separated, to address mid-band and high-frequency range issues while maintaining fluid resistance, including a first resonator for mid-band correction, a second for high-frequency attenuation, and a third for additional acoustic control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a single resonator is used in compact devices, then the device size is reduced, but the frequency response quality deteriorates with undesired peaks and roll-offs
Solution Approach 1:
The single resonator is divided into multiple resonators (first resonator for mid-band, second resonator for high-frequency) that operate independently to address different frequency ranges. This segmentation allows each resonator to be optimized for its specific frequency band, eliminating the frequency response peaks and roll-offs that occur with a single resonator while maintaining compact dimensions.
Solution Approach 2:
The resonators are spatially nested within the compact speaker module, with the second resonator positioned within the housing that also contains the first resonator. This nesting arrangement maximizes the use of available space, allowing multiple resonators to coexist in a small volume without compromising frequency response quality.
2Manufacturing precision
If multiple resonators are added to improve frequency response, then the audio quality is improved, but the device complexity increases
Solution Approach 1:
Multiple resonators are merged into a single integrated speaker module housing, sharing common structural elements and mounting mechanisms. The first and second resonators are both housed within the same module with shared acoustic pathways, reducing the overall complexity compared to separate resonator assemblies while maintaining the frequency response benefits of multiple resonators.
Solution Approach 2:
The speaker module housing serves multiple functions: it contains both resonators, provides acoustic isolation between them, manages sound output pathways, and maintains liquid resistance. This multi-functionality reduces the need for additional separate components, thereby reducing overall device complexity despite incorporating multiple resonators.
3Volume of moving object
If resonators are placed close together to save space, then the device compactness is improved, but acoustic interference between resonators occurs
Solution Approach 1:
Acoustic isolation structures serve as intermediaries between the first and second resonators, preventing direct acoustic coupling while allowing both resonators to operate in close proximity. These isolation elements block unwanted acoustic pathways between resonators, eliminating interference effects while maintaining the compact nested arrangement.
Solution Approach 2:
The housing structure incorporates localized acoustic isolation features at specific positions between resonators, rather than requiring uniform spacing throughout. This allows resonators to be positioned closely in some areas while maintaining acoustic separation where needed, achieving compactness without sacrificing acoustic performance.
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 provides a flattened high-frequency response and improved liquid resistance, enhancing audio quality in compact devices by redistributing sound pressure across a wider frequency band and simplifying manufacturing processes.
Implementation Method 1
Incorporating multiple Helmholtz resonators with independent frequency responses, spatially nested and acoustically separated, to address mid-band and high-frequency range issues
Data Source
AI summary
Aspects of the subject technology relate to electronic devices having speakers with resonators, such as Helmholtz resonators, acoustically coupled to the front volume of the speaker. A speaker module for an electronic device may include multiple resonators, including a first resonator that is acoustically separate from, and at least partially disposed within a second resonator. An acoustic barrier between the first resonator and the second resonator may have a liquid resistance that is different from a liquid resistance that is provided between the first resonator and a back volume of the speaker module and/or between an external environment of the speaker. In one or more implementations, a third resonator may be provided, that is spatially separated from first and second nested and/or adjacent resonators.