Headrest Loudspeaker Assembly With Front and Rear Helmholtz Resonators
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Solution Overview
Problem
Existing loudspeaker systems in headrests struggle to provide good sound quality at woofer frequencies, particularly in the near field for listeners resting their heads on the headrest.
Innovation Solution
A loudspeaker system is designed with a loudspeaker assembly integrated into the headrest, utilizing Helmholtz resonators and a baffle body to direct sound towards the listener's ears while minimizing unwanted vibrations and far-field emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a loudspeaker assembly is integrated into the headrest to provide woofer frequencies, then sound quality for listeners resting their heads on the headrest is improved, but unwanted vibrations and far-field emissions increase
Solution Approach 1:
The patent uses the unwanted vibrations generated by the woofer as a beneficial resource by routing them through a vibration transducer that converts them into audible sound waves. This transforms the harmful mechanical vibrations into useful acoustic output, improving sound quality while reducing the harmful vibration effects.
Solution Approach 2:
The patent introduces a vibration transducer as an intermediary component between the loudspeaker assembly and the listener's head. This mediator converts mechanical vibrations into acoustic waves, allowing the transmission of low-frequency sound without directly transmitting harmful vibrations to the listener's head.
2Reliability
If a loudspeaker assembly is integrated into the headrest to provide woofer frequencies, then sound quality for listeners resting their heads on the headrest is improved, but far-field sound emissions increase
Solution Approach 1:
The patent divides the sound transmission path into two separate segments: one for near-field acoustic output through the vibration transducer, and another for far-field emission control through the vent duct system. This segmentation allows optimized performance for each field - high directivity for near-field while controlling far-field emissions through directional venting.
Solution Approach 2:
The patent creates different acoustic qualities for different spatial zones: the near-field (listener's head position) receives high-quality, direct acoustic output through the vibration transducer, while the far-field emissions are controlled and directed through specific vent duct orientations, providing location-dependent sound quality characteristics.
3Ease of operation
If Helmholtz resonators are used to direct sound towards the listener's ears, then directivity is improved, but device complexity increases
Solution Approach 1:
The patent makes the vent duct system serve multiple functions: it acts as both a structural component of the loudspeaker assembly and as an acoustic directing mechanism for the Helmholtz resonators. This multi-functionality reduces the need for separate components, thereby reducing overall device complexity while maintaining improved directivity.
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 system achieves high directivity and good sound quality in the near field with minimized unwanted vibrations and reduced far-field sound emissions, enhancing the listening experience for individuals using the headrest.
Implementation Method 1
utilizing Helmholtz resonators and a baffle body to direct sound towards the listener's ears
Implementation Method 2
the loudspeaker system is constituted to issue sound within a frequency range, for example in an audible frequency range. For example, the frequency range of the loudspeaker assembly is a frequency range of at least one of a woofer or subwoofer
Data Source
AI summary
A loudspeaker system includes a loudspeaker assembly and a headrest having a front side and a rear side, the front side being constituted for resting a back side of a head of a person. The loudspeaker assembly is accommodated in the headrest with its front side oriented towards the front side of the headrest, the loudspeaker assembly including a first and a second driver each having a primary side and a secondary side for emitting sound, and first and second chambers, a part of the first chamber being limited by the primary side of the first driver and a part of the second chamber being limited by the primary side of the second driver. The assembly further includes a first front set of vent ducts venting the first chamber and terminating at the front side of the headrest, a second front set of vent ducts venting the second chamber and terminating at the front side of the headrest, at least one further chamber and at least one rear set of vent ducts. The secondary sides of the first and second drivers limit a part of one of the at least one further chamber or limit a part of different ones of the at least one further chamber, the at least one further chambers being respectively vented by a respective one of the at least one rear set of vent ducts terminating at the rear side of the headrest. The first and second chambers together with the front ducts form front Helmholtz resonators, the at least one further chamber together with the at least one rear set of vent ducts form at least one rear Helmholtz resonator.