Seat Back Resonator Reducing Low Frequency Distortion
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Solution Overview
Problem
Current vehicle sound systems, particularly those integrated into seatbacks and headrests, face challenges such as difficult access for maintenance, exposure to damp environments, and inefficient sound distribution, leading to suboptimal audio quality and spatialization processing.
Innovation Solution
A seat back with an improved sound system featuring a rigid enclosure and two sound transmission loudspeakers on either side of the headrest guides, incorporating an obliquely positioned resonator between the loudspeakers to reduce distortion and enhance HiFi sound quality, with the resonator oriented at 30 degrees relative to the backrest and loudspeaker outputs aligned with the resonator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If loudspeakers are installed in doors, then sound can be distributed throughout the vehicle, but access for maintenance becomes difficult and they are exposed to damp environments
Solution Approach 1:
The loudspeakers are extracted from the door panels and relocated to the seat back structure, specifically positioned in the headrest area. This extraction removes them from the damp door environment while maintaining their sound distribution function through the seat back's acoustic design
Solution Approach 2:
The seat back structure serves as an intermediary carrier for the loudspeakers, providing both structural support and acoustic transmission. The seat back acts as a mediator between the loudspeaker and the occupant's ear, delivering sound through the headrest region
2Volume of moving object
If loudspeakers are positioned farther from occupants' ears, then more space is available in the vehicle, but more energy is required for the same perceived power and spatialization processing becomes more difficult
Solution Approach 1:
The loudspeakers are positioned in the vertical dimension of the headrest rather than horizontally in the door panel. This dimensional relocation places the sound source closer to the occupant's ear in the vertical-z axis direction, reducing the effective distance for sound transmission while maintaining proper spatial distribution
3Reliability
If narrow sound ducts are used to convey sound close to the ear, then sound quality improves, but the ducts become awkward when the occupant turns their head or leans to one side
Solution Approach 1:
The sound transmission system is made dynamic by positioning the loudspeaker in the headrest structure that moves with the seat back. This allows the sound source to maintain its relative position to the occupant's ear even when the occupant moves their head, providing adaptive sound delivery without rigid fixed-position ducts
4Reliability
If a resonator is added to reduce distortion at low frequencies, then HiFi sound quality improves, but the device complexity increases
Solution Approach 1:
The resonator is merged with the existing seat back structure and integrated into the headrest assembly. Rather than adding a separate complex resonant system, the design combines the resonator function with the structural elements already present in the seat back, reducing overall device complexity while achieving HiFi sound quality
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 high-quality sound reproduction capable of handling both HiFi and standard audio broadcasts within a restricted vehicle volume, improving sound distribution and reducing distortion, especially when the occupant turns or leans, while being easily maintainable.
Implementation Method 1
the rigid enclosure comprising a resonator arranged between the loudspeakers making it possible to reduce distortion at low frequencies and to broadcast quality HiFi sound
Implementation Method 2
at least one electromagnetic transducer, in particular a loudspeaker, transforming an electrical signal into a sound wave
Data Source
Figure 1
Figure 2~4
AI summary
The invention relates to a seat back (10) comprising an improved sound-emitting device for the seat occupant, formed by a rigid chamber (11) covered by a lining (10a) and supporting two loudspeakers (16) for transmitting sound on each side of the guides (12) for the headrest poles, characterised in that the rigid chamber (11) comprises a resonator (20) disposed between the loudspeakers (16), allowing distortion at low frequencies to be reduced and a quality HiFi sound to be produced.