Speaker Module Rear Cavity Isolation for Thin Audio Design
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Solution Overview
Problem
The reduction in volume of the rear sound cavity of lightweight and thin speaker modules compromises sound quality, leading to poor audio experiences in electronic devices.
Innovation Solution
A speaker module design incorporating a sound-absorbing particle-filled rear sound cavity, separated by a breathable isolating member and fixing ring, which expands the acoustic volume and prevents particle intrusion into the electroacoustic transducer, maintaining sound quality while allowing a thin and lightweight structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the speaker module is designed to be lightweight and thin, then the mounting space and device thickness are reduced, but the rear sound cavity volume decreases leading to poor sound quality
Solution Approach 1:
The breathable isolating member is positioned within the speaker module structure to divide the sound cavity into front and rear portions. This nested arrangement allows the rear sound cavity to be effectively expanded within the constrained thin profile of the speaker module, enabling improved low-frequency performance without increasing overall device thickness
Solution Approach 2:
The sound membrane is configured to divide the sound cavity in the thickness direction, creating distinct front and rear sound cavities. This dimensional approach allows the rear sound cavity volume to be increased within the limited space by utilizing the thickness dimension efficiently, thereby improving sound quality without increasing the speaker module's overall footprint
2Reliability
If sound-absorbing particles are added to the rear sound cavity to improve sound quality, then acoustic performance is enhanced, but particles may intrude into the electroacoustic transducer causing damage
Solution Approach 1:
The breathable isolating member serves as an intermediary barrier between the rear sound cavity containing sound-absorbing particles and the electroacoustic transducer. It allows acoustic energy to pass through while physically blocking particles from entering the transducer, thus protecting the voice coil and magnetic circuit from particle contamination
Solution Approach 2:
The breathable isolating member is designed with porous or mesh-like structure that permits acoustic wave transmission while maintaining physical separation. This porous configuration enables sound to pass through the isolating member while the particle-sized openings prevent sound-absorbing particles from penetrating into the electroacoustic transducer
3Object-affected harmful factors
If an isolation assembly is added to separate sound-absorbing particles from the electroacoustic transducer, then particle intrusion is prevented, but the device complexity increases
Solution Approach 1:
The breathable isolating member is integrated into the existing speaker module structure, serving multiple functions simultaneously: it acts as a physical barrier to prevent particle intrusion, maintains acoustic coupling between front and rear cavities, and provides structural support. This multi-functionality reduces the need for additional separate isolation components, thereby minimizing the increase 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
Enhances low-frequency performance and sound quality by expanding the rear sound cavity volume, preventing particle intrusion, and ensuring a compact, lightweight design without affecting the electroacoustic transducer's size or magnetic circuit performance.
Implementation Method 1
sound-absorbing particles are filled in the rear sound cavity
Implementation Method 2
The breathable isolating member is fixedly connected to an upper surface of the fixing ring, and is located between the hole wall of the avoidance hole and the lower pole piece. The breathable isolating member is arranged surrounding the electroacoustic transducer, and is configured to isolate the sound-absorbing particles and the electroacoustic transducer
Data Source
Figure 1~2A
Figure 2B
Figure 3
AI summary
This application provides a speaker module and an electronic device, to improve a sound quality experience of the speaker module. The speaker module includes a first housing, a second housing, an electroacoustic transducer, sound-absorbing particles, a fixing ring, and a breathable isolating member. The second housing is mounted in the first housing, and is enclosed with the first housing to form a sound cavity. An avoidance hole is provided on the second housing, and the avoidance hole is in communication with the sound cavity and an outer side of the second housing. The electroacoustic transducer is mounted in the sound cavity. The electroacoustic transducer includes a lower pole piece and a sound membrane. The lower pole piece runs through the avoidance hole, and is spaced apart from a hole wall of the avoidance hole. The sound membrane is spaced apart from the lower pole piece, and divides the sound cavity into a front sound cavity and a rear sound cavity. The sound-absorbing particles are filled in the rear sound cavity. The fixing ring is mounted between the second housing and the lower pole piece, and is arranged surrounding an edge of the lower pole piece. The breathable isolating member is fixedly connected to an upper surface of the fixing ring, and is located between the hole wall of the avoidance hole and the lower pole piece. The breathable isolating member is arranged surrounding the electroacoustic transducer, and is configured to isolate the sound-absorbing particles and the electroacoustic transducer.