Speaker Module Sealed Cavity Helmholtz Resonator
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing speaker modules experience sharp and distorted sound due to high sound pressure levels (SPL) at the resonant frequency (Fh), leading to compromised sound quality, as increasing damping in the front cavity to reduce SPL at Fh often results in decreased SPL in other frequency bands.
Innovation Solution
A speaker module design incorporating a sealed cavity on the side wall of the sound passage of the front cavity, connected through a communication hole, forms a resonant energy absorption structure that filters out high-frequency sound waves, reducing SPL at Fh and improving harmonic distortion by acting as a Helmholtz resonator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If damping is increased by attaching sound absorbing material in the front cavity, then the SPL at Fh is reduced, but the SPL in other frequency bands (especially near f0) is reduced
Solution Approach 1:
The patent introduces a sealed cavity with specific volume (0.008cc to 0.1cc) connected through a communication hole with specific dimensions (diameter 0.3mm to 1.5mm, length 0.4mm to 0.8mm) at a specific location on the side wall of the sound passage. This localized structural modification creates a Helmholtz resonator that selectively targets the Fh frequency for energy absorption while preserving acoustic performance in other frequency bands, particularly near f0.
Solution Approach 2:
The patent changes the physical parameters of the cavity system by adding a sealed cavity with controlled volume (0.008cc to 0.1cc) and a communication hole with specific dimensions. This parameter change transforms the acoustic behavior at Fh frequency, creating a resonant absorption mechanism that reduces SPL at Fh without the broad-band damping effect that would harm other frequencies.
2Object-generated harmful factors
If damping is increased to reduce SPL at Fh, then the harmonic distortion is improved, but the overall acoustic performance in other frequency bands deteriorates
Solution Approach 1:
The sealed cavity structure is locally positioned on the side wall of the sound passage with precise dimensional specifications. This localized Helmholtz resonator configuration provides targeted harmonic distortion reduction at Fh frequency while maintaining acoustic performance reliability in other frequency bands, avoiding the broad-band suppression that would result from general damping approaches.
Solution Approach 2:
The patent converts the harmful resonant energy at Fh frequency into beneficial acoustic absorption by creating a Helmholtz resonator. The sealed cavity with communication hole is designed to resonate at Fh frequency, absorbing the harmful resonant energy and converting it into minimal useful output, thereby reducing harmonic distortion while preserving overall acoustic performance.
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 resonant energy absorption structure effectively reduces SPL at Fh and improves sound quality by filtering high-frequency sound waves, resulting in a more euphonic sound and reduced harmonic distortion, as demonstrated by the sensitivity and distortion test curves before and after implementation.
Implementation Method 1
The principle thereof is to form a Helmholtz resonator by the sealed cavity and the communication hole, which absorbs parts of the acoustic energy by resonating with the incident sound waves at Fh
Implementation Method 2
the sealed cavity and the sound passage of the front cavity form a resonant energy absorption structure, so as to filter out some of the high-frequency sound waves
Data Source
AI summary
Provided is a speaker module, comprising a sound passage of a front cavity, wherein the sound passage is defined by a speaker unit, a housing and a sound hole provided on the housing, wherein the speaker module further comprises a sealed cavity and a communication hole, wherein the sealed cavity is provided on a side wall of the sound passage of the front cavity, and the sealed cavity is in communication with the sound passage of the front cavity via the communication hole. By means of the present invention, an SPL peak at Fh and harmonic distortion caused by front cavity resonance can be reduced, so that the acoustic performance of a speaker is enhanced, and the sound quality is improved.