Coaxial Speaker Microphone Arrangement for Echo Reduction
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Solution Overview
Problem
Existing voice-enabled devices face challenges in enhancing acoustic performance due to interference from background voices, ambient noise, and double talk, which negatively impact both input and output audio quality.
Innovation Solution
A voice controlled assistant with a coaxially aligned speaker and microphone arrangement is implemented, featuring a microphone array and a speaker array configured to minimize echo and double talk interference, thereby improving audio signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If microphones are used to receive voice input, then speech recognition capability is enabled, but acoustic echo and double talk interfere with input quality
Solution Approach 1:
The patent extracts and removes the harmful acoustic echo and double talk components from the microphone input signal through signal processing techniques, isolating the desired near-end speaker voice from interfering sounds
Solution Approach 2:
The patent uses feedback from the speaker output to the microphone input to model and cancel acoustic echo, continuously adjusting the cancellation based on the detected echo path between speaker and microphone
2Ease of operation
If loudspeakers are used to output audio, then far end talker communication is enabled, but acoustic echo reaches microphones and degrades input quality
Solution Approach 1:
The patent converts the harmful acoustic echo into a useful signal by using it to train echo cancellation algorithms, where the known speaker output combined with the captured echo allows modeling and subsequent removal of echo from the microphone input
Solution Approach 2:
The patent introduces an intermediary echo cancellation processing stage between the microphone input and speech recognition, which mediates by removing acoustic echo and double talk components before the clean signal reaches the recognition system
3Reliability
If coaxial speaker and microphone arrangement is implemented, then acoustic echo and double talk are reduced, but device structure becomes more complex
Solution Approach 1:
The patent merges the speaker and microphone arrays into a coaxial configuration, aligning them along the same axis to exploit geometric symmetry for echo cancellation, where the overlapping spatial arrangement simplifies the acoustic model compared to separate array configurations
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 coaxial arrangement effectively reduces acoustic echoes and double talk, enhancing the overall acoustic performance of the voice controlled assistant by isolating the near talker's voice and improving signal quality for accurate speech recognition.
Implementation Method 1
sound from the near end talker reaches the microphones simultaneously with sound from the far end talker that is played out through the device loudspeakers
Implementation Method 2
These additional sounds concurrent with the speech input can negatively impact acoustic performance of the device
Data Source
AI summary
A voice controlled assistant has a housing to hold one or more microphones, one or more speakers, and various computing components. The housing has an elongated cylindrical body extending along a center axis between a base end and a top end. The microphone(s) are mounted in the top end and the speaker(s) are mounted proximal to the base end. The microphone(s) and speaker(s) are coaxially aligned along the center axis. The speaker(s) are oriented to output sound directionally toward the base end and opposite to the microphone(s) in the top end. The sound may then be redirected in a radial outward direction from the center axis at the base end so that the sound is output symmetric to, and equidistance from, the microphone(s).