Directional Microphone Placement for Echo Reduction
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Solution Overview
Problem
Conventional omni-directional microphones used in ear-hole sound transmitters/receivers suffer from echo and howling issues due to simultaneous input and output of sound, requiring complex signal processing, which increases size and manufacturing costs, and reduces Signal-to-Noise Ratio (SNR).
Innovation Solution
A directional microphone is positioned with low sensitivity at the side of the sound waveguide to attenuate echo and howling, and the sound output unit is placed where sensitivity is low, while the directional microphone detects sound through holes with high sensitivity, improving SNR and reducing interference noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an omni-directional microphone is used in an ear-hole sound transmitter/receiver, then sound can be received from all directions, but echo and howling occur due to simultaneous input and output of sound in the ear hole
Solution Approach 1:
The patent applies local quality by creating different acoustic environments for different directions. The sound waveguide has different structures at its two ends: one end has a microphone for receiving sound, while the other end has a speaker for outputting sound. This asymmetric design ensures that sound waves traveling from the microphone to the speaker do not create echo, while still allowing omni-directional sound reception at the microphone end.
2Object-generated harmful factors
If complex signal processing is applied to eliminate echo and howling, then echo and howling are reduced, but the size and manufacturing/development costs increase
Solution Approach 1:
The patent converts the potential harmful effect of sound waves traveling through the ear hole into a beneficial design feature. By designing the sound waveguide with asymmetric structures at its two ends (microphone end vs. speaker end), the patent allows sound waves to pass through without creating echo, effectively using the physical structure to eliminate the need for complex signal processing while maintaining omni-directional sound reception.
3Object-generated harmful factors
If a directional microphone is used to reduce echo, then echo and howling are attenuated, but sound reception from all directions is reduced
Solution Approach 1:
The patent applies segmentation by dividing the sound waveguide into two distinct functional segments: one segment (the microphone end) is designed for omni-directional sound reception, while the other segment (the speaker end) is designed for sound output. This segmentation allows each part to perform its specific function optimally without compromising the other, achieving both echo reduction and omni-directional reception.
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 effectively reduces echo and howling, enhances SNR, and minimizes interference noise, allowing for efficient sound detection and full duplexing without complex signal processing.
Implementation Method 1
a directional microphone for detecting the second sound by the through holes of the sound waveguide
Implementation Method 2
a sound output unit disposed at said one opening of the sound waveguide to output the first sound to the sound waveguide
Data Source
AI summary
The apparatus for transmitting and receiving sound is disclosed, wherein a directional microphone for detecting sound for transmission is applied and a sound output unit for outputting the received sound is arranged at a side of the directional microphone where sensitivity is low, thereby preventing sound coupling for received sound and sound for transmission without recourse to complicated signal processing to attenuate the echo and howling.