Three-Part Speaker Membrane Stiffening Ring
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Solution Overview
Problem
Low-profile speaker drivers in devices like earphones and portable computers face issues with sound pressure output due to natural structural resonances at specific frequencies, leading to undesirable sound pressure drops at breaking mode frequencies.
Innovation Solution
A three-part speaker assembly membrane with a sound radiating surface, a concentrically positioned stiffening ring, and a suspension member, where the stiffening ring is made of a material with greater stiffness or density than the other components, locally stiffening the area to increase the breaking mode frequency above the working range of the driver.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a low-profile diaphragm assembly with two parts (SRS and suspension member) is used, then the speaker can be integrated into devices with limited space, but the natural structural resonances of the components cause out-of-phase movements at breaking mode frequencies, resulting in undesirable sound pressure drops
Solution Approach 1:
The diaphragm assembly is divided into three distinct parts: the sound radiating surface (SRS), the stiffening ring, and the suspension member. This segmentation allows each component to have optimized properties - the SRS for sound radiation, the stiffening ring for structural stability, and the suspension member for mechanical support - thereby resolving the contradiction between low profile and sound pressure stability.
Solution Approach 2:
A stiffening ring is introduced at the specific location between the SRS and suspension member to provide localized structural reinforcement. This local quality enhancement increases the breaking mode frequency of the assembly without requiring a complete redesign of the entire diaphragm structure, maintaining the low-profile advantage while improving sound pressure output stability.
2Ease of manufacture
If the SRS and suspension member are designed with standard materials and structures, then the assembly remains simple and manufacturable, but the breaking mode frequency falls within the working range, causing out-of-phase movements and sound pressure drops
Solution Approach 1:
The stiffening ring is constructed from composite materials or multi-layer structures that provide high stiffness and strength-to-weight ratio. This allows the ring to effectively increase the breaking mode frequency and prevent out-of-phase movements while maintaining ease of manufacture through conventional material processing techniques.
Solution Approach 2:
The stiffness, density, and geometric parameters of the stiffening ring are specifically optimized to shift the breaking mode frequency above the working range. By adjusting these parameters, the assembly achieves improved acoustic performance without complicating the manufacturing process, as the ring can be produced using standard fabrication methods.
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 effectively increases the breaking mode frequency, minimizing undesirable sound pressure drops within the driver's operational range, resulting in improved acoustic performance by maintaining sound pressure output across the desired frequency range.
Implementation Method 1
the second material is stiffer than the first material and the third material so as to locally stiffen an area surrounding the SRS and improve a breaking mode frequency of the membrane
Implementation Method 2
The SRS vibrates axially thereby creating pressure waves outside the driver enclosure
Implementation Method 3
The suspension surrounds and suspends the SRS within the enclosure and allows it to vibrate axially
Data Source
AI summary
A speaker assembly membrane including a sound radiating surface (SRS) having a first material; a substantially planar SRS ring positioned concentrically outward from the SRS and having a second material; and a suspension member positioned concentrically outward from the SRS ring and having a third material. The second material is stiffer than the first material and the third material to locally stiffen an area surrounding the SRS and improve a breaking mode frequency of the membrane. In another embodiment, the speaker assembly membrane may include a diaphragm having a first material density; a substantially planar stiffening ring extending radially outward from an outer edge of the diaphragm and having a second material density; and a suspension member extending radially outward from an outer edge of the stiffening ring and having a third material density. The second material density is greater than the first material density and the third material density.