Variable Port Microphone Waveguide Directivity
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Solution Overview
Problem
Conventional microphone arrays face challenges in achieving high directivity at both low and high frequencies, often requiring multiple microphones and resulting in increased self-noise and reduced performance.
Innovation Solution
The proposed microphone assembly configuration includes two waveguides with high-frequency and low-frequency ports arranged at specific distances and impedances, utilizing materials with different impedances and inertance to enhance frequency selectivity and directivity, allowing for improved performance with fewer microphones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional microphone arrays use multiple microphones to achieve high directivity at both low and high frequencies, then directivity performance is improved, but self-noise increases and device complexity increases
Solution Approach 1:
The invention divides the frequency spectrum into low-frequency and high-frequency bands, using separate waveguide paths with different port configurations for each band. This segmentation allows optimized directivity control for each frequency range independently, achieving high overall directivity without requiring a large array of microphones that would increase self-noise.
Solution Approach 2:
The waveguides are designed with location-specific port characteristics: low-frequency ports are positioned at certain distances from the microphone with specific impedance values, while high-frequency ports are positioned at different distances with different impedance values. This local quality differentiation enables frequency-selective directivity control, improving measurement precision across the full frequency range while using fewer microphones.
2Measurement precision
If conventional microphone arrays use multiple microphones to achieve high directivity at both low and high frequencies, then directivity performance is improved, but device complexity increases
Solution Approach 1:
Each waveguide structure serves multiple functions: it guides acoustic waves, provides frequency-selective port access, and creates direction-dependent interference patterns. The same waveguide component handles both low-frequency and high-frequency signals through its multiple ports, reducing the need for separate specialized components and simplifying the overall device architecture.
Solution Approach 2:
The invention varies key parameters (port distance from microphone, port impedance, port position) to optimize performance for different frequency ranges. By adjusting these parameters, the system achieves high directivity across the full frequency spectrum using a unified waveguide structure rather than complex multi-microphone arrays.
3Measurement precision
If waveguide ports are arranged with different distances and impedances for low and high frequencies, then frequency selectivity and directivity are improved, but manufacturing precision requirements increase
Solution Approach 1:
The waveguide structure is designed with pre-calculated port positions and impedance values that are optimized for the desired frequency response. These parameters are determined in advance through acoustic modeling and simulation, allowing manufacturers to follow precise design specifications rather than requiring complex real-time adjustments, thereby reducing actual manufacturing 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
This configuration achieves high directivity at frequencies ranging from 100 Hz to 15000 Hz, reducing self-noise and increasing directive performance, thereby improving microphone array efficiency and performance.
Implementation Method 1
The first and second low-frequency ports have a first impedance, wherein the first and second high-frequency ports have a second impedance
Implementation Method 2
the first and second low-frequency ports are covered with one or more materials or geometric features which provide an inertance
Implementation Method 3
The microphone assembly has a first directivity at low frequencies ranging from approximately 100-1000 Hz and high frequencies ranging from approximately 2000-6000 Hz
Data Source
AI summary
A microphone assembly for providing improved directivity at high and low frequencies is disclosed. The microphone assemblies comprise two waveguides each having a microphone, a high-frequency port, and a low-frequency port. The two waveguides are arranged adjacent to each other so that the two low-frequency ports are arranged at a first distance apart from each other and so that the two high-frequency ports are arranged at a second distance apart from each other. The microphone assemblies may comprise two additional waveguides of different length than the first two waveguides, where the two additional waveguides also have low frequency ports and high frequency ports. When the four waveguides are arranged adjacent to each other, all the low-frequency ports are at one distance from each other and all the high-frequency ports are at another distance from each other.