Elliptical Acoustic Waveguide for Wider Headrest Sound Field
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Solution Overview
Problem
The fixed sound field of vehicle speakers results in poor sound listening experience due to the user's ear deviating from the sound field when their head shakes.
Innovation Solution
An acoustic waveguide with an elliptical sound outlet and a sound guide channel that expands the sound field in a preset direction, ensuring the ear remains within the sound field despite head movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If a circular sound outlet is used, then the sound field width is limited, but the structure is simple and manufacturing is easy
Solution Approach 1:
The sound outlet is designed with an elliptical cross-section instead of a circular one, creating asymmetric geometry that expands the sound field width in the horizontal direction. This asymmetric shape allows the major axis to be longer than the diameter of an equivalent circular outlet, thereby increasing sound field coverage without requiring complex manufacturing processes, as elliptical shapes can be easily formed through standard molding techniques.
Solution Approach 2:
The invention transitions from a circular (one-dimensional symmetry) to an elliptical (two-dimensional asymmetry) sound outlet configuration. By utilizing the elliptical geometry with distinct major and minor axes, the sound field is expanded in the horizontal dimension while maintaining vertical compactness, effectively using dimensional transformation to increase sound field width without proportionally increasing overall volume or manufacturing complexity.
2Adaptability or versatility
If the sound field width is increased to accommodate head movement, then sound listening experience is improved, but the device complexity increases
Solution Approach 1:
The sound guide channel is designed with an asymmetric elliptical cross-section that is optimized for horizontal sound field expansion. This asymmetric geometry allows the waveguide to naturally guide sound waves in a pattern that covers a wider horizontal area, accommodating typical head movement ranges. The asymmetric design achieves adaptability without requiring multiple adjustable components or complex mechanical structures.
Solution Approach 2:
The invention optimizes specific geometric parameters of the sound guide channel, including the aspect ratio of the elliptical cross-section, the length of the major axis, and the curvature of the channel walls. By carefully selecting these parameters, the sound field coverage is maximized for the intended application while keeping the overall structure simple and manufacturable, thus achieving high adaptability without proportional increases in device complexity.
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 elliptical sound outlet design maintains the ear within the sound field, enhancing sound listening experience by preventing deviation and ensuring consistent sound quality.
Implementation Method 1
After a sound wave is emitted by the sound source, the sound wave enters the sound guide channel through the sound inlet, and the sound wave is propagated from the sound inlet to the sound outlet in the sound guide channel
Implementation Method 2
A shape of the sound field at the sound outlet is the same as a shape of the sound outlet. In comparison with a circular sound outlet with an equal area, the major axis of the elliptical shape is greater than a diameter of a circle. Therefore, a width of the sound field at the elliptical sound outlet in a direction parallel to the major axis is greater than a width of a sound field at the circular sound outlet
Data Source
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AI summary
An acoustic waveguide, a speaker assembly, a vehicle headrest, and a vehicle are provided, to resolve a problem that when a head of a user shakes, an ear of the user easily deviates from a sound field, resulting in poor driving experience. A sound guide channel is provided on a sound guide body in the acoustic waveguide, the sound guide channel includes a sound inlet and a sound outlet, the sound inlet is provided directly opposite to a sound source, the sound outlet is in an elliptical shape, a major axis of the elliptical shape is parallel to a preset direction, and the preset direction is related to a sound field expansion direction, to increase a width of the sound field in the preset direction. In this way, when the head of the user shakes, the ear of the user can always be kept in the sound field. This prevents the ear of the user from deviating from the sound field, and improves driving experience.