Loudspeaker Protruding Inner Surface Reduces Intermodulation Distortion
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Solution Overview
Problem
Conventional loudspeakers suffer from intermodulation distortion due to frequency response variations caused by the movement of the driver diaphragm, which results in unwanted acoustic phenomena.
Innovation Solution
The design incorporates a driver diaphragm, enclosure, and outlet configuration where the inner surface of the enclosure has a protruding part closer to the driver diaphragm, reducing the chamber width and introducing a variable-width extension to the outlet, effectively forming a combination of acoustical inductor and capacitor components that minimize frequency response variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the chamber width is reduced by adding a protruding part close to the outlet, then the frequency response variation is minimized and intermodulation distortion is reduced, but the device complexity increases
Solution Approach 1:
The patent applies local quality by adding a protruding part only in the specific region close to the outlet where it is most needed to minimize frequency response variation. This localized modification reduces intermodulation distortion without requiring a complete redesign of the entire enclosure structure, thus balancing performance improvement with structural simplicity.
2Reliability
If the outlet is extended with a variable-width structure, then the acoustical inductor and capacitor effects are enhanced to reduce intermodulation distortion, but the manufacturing complexity increases
Solution Approach 1:
The outlet structure is segmented into different regions with varying widths, creating a variable-width extension that provides the desired acoustical inductor and capacitor effects. This segmentation allows for simplified manufacturing by breaking down the complex outlet structure into manageable sections that can be produced using standard fabrication processes.
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 reduces intermodulation distortion by maintaining a relatively constant resonance frequency, as demonstrated by reduced two-tone and multitone intermodulation distortion measurements compared to conventional designs.
Implementation Method 1
The driver diaphragm is configured to produce acoustic waves
Implementation Method 2
The outlet works an acoustical inductor
Implementation Method 3
the chamber works as an acoustical capacitor
Implementation Method 4
The width of the chamber changes with the movement of the driver diaphragm, resulting in the capacitance variation of the capacitor. The capacitor and the inductor cause the variation of the frequency response that causes the intermodulation distortion.
Data Source
AI summary
A loudspeaker is disclosed, including a driver diaphragm, an enclosure and an outlet. The driver diaphragm is configured to produce acoustic waves. The enclosure includes an upper wall disposed opposite to the driver diaphragm and having an inner surface facing to the driver diaphragm, and a side wall connecting the upper wall to the driver diaphragm. The outlet is defined at the upper wall or the side wall, and configured to output the acoustic waves. The driver diaphragm and the enclosure define a front volume chamber communicating with the outlet. The front volume chamber and the outlet form a front cavity. The inner surface has a protruding part located close to the outlet, a distance from a position at the protruding part to the driver diaphragm is smaller than that from a position at other parts of the inner surface to the driver diaphragm.