Helmholtz Resonators Reduce Speaker-Microphone Acoustic Coupling
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Solution Overview
Problem
In mobile apparatus, strong acoustical coupling between the speaker and microphone leads to significant echo generation, which is difficult to mitigate with existing digital signal processing algorithms, especially in low-cost devices with limited processing power.
Innovation Solution
The design incorporates Helmholtz resonators or acoustic absorbing materials at critical sound pressure level points to alter the acoustic coupling path, reducing echo generation by changing the intrinsic mode of acoustical coupling and absorbing sound energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If digital signal processing algorithms are used to manage echoes, then echo cancellation capability is improved, but processing power requirements and device complexity increase
Solution Approach 1:
The patent converts the harmful acoustic coupling between speaker and microphone into a beneficial solution by using Helmholtz resonators and acoustic absorbing materials. These components exploit the acoustic field itself to reduce echo generation at the source, transforming the problematic acoustic interaction into a controlled acoustic environment that naturally suppresses echoes without requiring complex digital signal processing
Solution Approach 2:
The patent introduces Helmholtz resonators and acoustic absorbing materials as intermediary elements between the speaker and microphone. These intermediaries modify the acoustic coupling path by creating specific resonance frequencies and absorbing sound energy, thereby reducing the direct acoustic interaction that causes echoes while maintaining the functional relationship between speaker and microphone
2Reliability
If DSP algorithms are enhanced to reduce echoes, then call quality is improved, but power consumption increases
Solution Approach 1:
The patent converts the harmful acoustic coupling into a beneficial acoustic environment by using passive Helmholtz resonators and absorbing materials. This physical approach reduces echo generation at the source, improving call quality without requiring additional power for complex DSP algorithms, as the echo reduction is achieved through acoustic design rather than computational processing
3Volume of moving object
If the coupling path between speaker and microphone is shortened for compact design, then device size is reduced, but acoustical coupling strength increases
Solution Approach 1:
The patent applies local quality by placing Helmholtz resonators and acoustic absorbing materials at specific locations within the compact device housing. These components are strategically positioned in the acoustic coupling path between speaker and microphone to create localized acoustic zones that reduce coupling strength without requiring increased device dimensions. The resonators are tuned to specific frequencies to target the predominant echo paths in the compact form factor
Solution Approach 2:
The patent introduces Helmholtz resonators and acoustic absorbing materials as intermediary elements within the compact device structure. These intermediaries modify the acoustic coupling path by creating resonance effects and absorbing sound energy at critical points, thereby reducing the strength of acoustic coupling between speaker and microphone despite the short physical distance imposed by compact device design
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 effectively reduces acoustical coupling and echo generation, improving call quality in mobile devices without increasing processing power requirements, as demonstrated by simulations and test results showing decreased acoustic coupling across various frequencies.
Implementation Method 1
The design incorporates Helmholtz resonators or acoustic absorbing materials at critical sound pressure level points to alter the acoustic coupling path
Implementation Method 2
The design incorporates Helmholtz resonators or acoustic absorbing materials at critical sound pressure level points to alter the acoustic coupling path, reducing echo generation by changing the intrinsic mode of acoustical coupling and absorbing sound energy
Data Source
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AI summary
An apparatus comprising: at least one speaker; and at least one microphone, wherein there is an acoustic coupling between the at least one speaker and the at least one microphone; at least one location defined by the at least one acoustic coupling between the apparatus at least one speaker and the apparatus at least one microphone; and at least one dampening element at the determined location, such that the at least one acoustic coupling between the at least one speaker and the at least one microphone is substantially reduced.