Headrest Speaker Assembly with Fabric Flapping Prevention
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Solution Overview
Problem
Existing headrests with integrated speakers face challenges in enhancing stereo feeling within limited space, as the speakers' proximity leads to sound interference and degradation of acoustic characteristics due to the flapping of three-dimensional fabric materials at resonance frequencies.
Innovation Solution
The headrest incorporates sound-emitting direction regulating members with annular portions that project forward to surround the speakers' diaphragms, combined with a tensioned three-dimensional fabric that bites into these members, and a sound propagation preventing part, such as foam, between adjacent members to regulate sound emission and prevent interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If speakers are arranged close together in the headrest to save space, then the headrest size is reduced, but sound interference occurs and stereo feeling deteriorates
Solution Approach 1:
A sound propagation preventing part (foam material) is introduced as an intermediary between adjacent speakers to block sound waves from interfering with each other. This mediator prevents harmful acoustic interactions while allowing the speakers to remain in close proximity within the headrest structure.
Solution Approach 2:
The sound propagation preventing part is strategically placed only in specific locations between speakers where sound interference occurs, rather than throughout the entire headrest. This localized approach prevents acoustic interference while maintaining overall space efficiency and stereo imaging.
2Ease of operation
If three-dimensional fabric is used in the speaker area, then comfort is improved, but flapping occurs at resonance frequencies degrading acoustic characteristics
Solution Approach 1:
The three-dimensional fabric is removed from direct contact with the speaker diaphragms and sound emission paths. By extracting the fabric from these critical acoustic zones, the harmful flapping motion at resonance frequencies is eliminated while the fabric can still provide comfort in non-critical areas.
Solution Approach 2:
The headrest is divided into distinct functional zones: acoustic zones where fabric-free speaker assemblies are positioned to prevent flapping, and comfort zones where three-dimensional fabric can be used for head support. This segmentation allows both acoustic quality and comfort requirements to be satisfied in their respective areas.
3Reliability
If speakers are positioned to achieve good stereo effect, then sound quality improves, but the required space increases beyond available headrest dimensions
Solution Approach 1:
Sound propagation preventing parts are used as intermediaries to block reflected and leaked sound between closely spaced speakers. This allows speakers to be positioned closer together than traditional stereo spacing would require, achieving compact integration while maintaining stereo effect through the mediator's interference-blocking function.
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 the stereo feeling by preventing sound interference and maintaining acoustic quality, even with speakers closely spaced, by regulating sound direction and reducing flapping, thereby improving sound pressure levels and overall sound quality.
Implementation Method 1
a three-dimensional fabric that is tensioned and arranged in a state where each of the annular portions of each of the sound-emitting direction regulating members bites into the three-dimensional fabric
Implementation Method 2
a sound propagation preventing part, such as foam, between adjacent members to regulate sound emission and prevent interference
Data Source
Figure 1(a)~1(e)
Figure 2
Figure 3
AI summary
The present invention prevents a three-dimensional fabric arranged in front surfaces of speakers from flapping due to sound. In the respective front surface sides of speakers 20, 30, sound-emitting direction regulating members 23, 33 that include annular portions 231, 331 that project forward by a predetermined distance are arranged. A three-dimensional fabric 421 is tensioned and arranged so as to cover the front surface sides of the sound-emitting direction regulating members 23, 33. When the three-dimensional fabric 421 is pressed against the annular portions 231, 331 configuring the sound-emitting direction regulating members 23, 33, the annular portions 231, 331 bite into the three-dimensional fabric 421 since the three-dimensional fabric 421 has a predetermined thickness. The annular portions 231, 331 are provided so as to surround diaphragms 221, 321 of the speakers 20, 30. Sound output from the speakers 20, 30 passes inside the annular portions 231, 331. However, the periphery of a region of the three-dimensional fabric 421 in which sound passes is supported by the biting of the annular portions 231, 331, thereby preventing the three-dimensional fabric 421 from flapping widely in response to the sound.