Nested Loudspeaker Drive Unit Baffle Design
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Solution Overview
Problem
Existing compound loudspeaker designs suffer from acoustical mismatches and diffraction issues due to geometrical discontinuities, leading to impaired frequency response and directivity control, particularly between the high frequency diaphragm and low frequency cone.
Innovation Solution
A dual radial suspension diaphragm utilizing a push-pull linearization principle for axial motion, with a rigid chassis and flexible suspension elements, ensures continuous acoustical coupling and minimizes abrupt geometrical discontinuities, reducing harmonic distortion and diffraction products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the high frequency diaphragm is elevated forward from the low frequency cone neck, then the high frequency driver can be mounted, but acoustical mismatch occurs causing comb-filter effect and degraded frequency response
Solution Approach 1:
The patent introduces a specially designed baffle structure as an intermediary element between the high frequency diaphragm and the low frequency cone. This baffle provides a smooth acoustical transition surface that eliminates the comb-filter effect while maintaining proper mounting geometry, thus resolving the contradiction between mounting capability and frequency response quality.
2Ease of operation
If a circular gap is left between the cone and high frequency driver annular baffle to allow axial movement, then mechanical motion is enabled, but diffraction occurs degrading frequency response
Solution Approach 1:
The patent replaces the circular gap with a smoothly curved baffle surface that maintains continuous acoustical coupling. The curved geometry allows axial movement of the low frequency cone while eliminating the diffraction effects caused by sharp edges, thus resolving the contradiction between mechanical motion capability and frequency response quality.
3Manufacturing precision
If the surround geometry is modified to reduce diffraction, then frequency response improves, but mechanical complexity increases
Solution Approach 1:
The patent combines the baffle structure with the surround geometry into an integrated component. This merging eliminates the need for separate diffraction-reducing features while maintaining smooth acoustical transitions, thus improving frequency response without increasing mechanical complexity.
4Adaptability or versatility
If separate high frequency units are attached in front of or close to the low frequency voice coil, then compound loudspeaker function is achieved, but acoustical mismatch and directivity irregularities occur
Solution Approach 1:
The patent implements a nested configuration where the high frequency driver is positioned within the magnetic structure of the low frequency driver. This nesting arrangement maintains concentric alignment of the drive units, eliminating directivity irregularities while achieving compound loudspeaker function across multiple frequency ranges.
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 approach results in smoother frequency response, improved directivity control, and reduced acoustic harmonic distortion, enabling more efficient sound radiation with simpler mechanical construction and economical production.
Implementation Method 1
a voice coil, which is moved by an electromechanical force generated by a voice coil
Implementation Method 2
which is radiating sound waves into the air
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A loudspeaker driver (22) also suitable for compound applications comprising a rigid speaker frame (11, 13, 15, 19, 8) to which is attached a permanent magnet (13) with which a voice coil winding (9) is adapted to interact through electromagnetic force. The voice coil winding (9) is adapted to deliver axial motion to a diaphragm assembly (21), which includes an elastic outer section (2), whose outer rim (5) is attached to the outer part of the speaker frame (11). The diaphragm assembly (21) comprises an essentially rigid primary vibrating diaphragm (4) attached between the elastic outer section (2) and an elastic inner section (3), whose inner rim (10) is attached to the inner part of said speaker frame (8). Said voice coil winding (9) is fixed to the primary vibrating diaphragm (4) through said voice coil former (6), which is adapted to move said diaphragm assembly (21).