Dual Inline Microphone Noise Cancelling
I would like to mimic a noise cancelling differential microphone using two omni-directional microphones that are oriented in-line with the audio path.
An example of this would be your bluetooth headset, which uses dual inline microphones to ignore far field noise sources and amplifiy the audio coming from your mouth, along your face, to mic1, and then to mic2. Noise that hits mic1 and mic2 simultaneously, or mic2 before mic1, is attentuated, which allows for the far field noise to be removed.
Are there any plans to implement such an algorithm in the SigmaDSP line? Can this be achieved using standard blocks already present?
noise_cancelling
microphone
sigmastudio
differential
A noise cancelling configuration using two omindirectional microphones can be easily implemented in SigmaStudio using standard processing blocks. To get a noise cancelling configuration (or figure-8, so-called for the polar pattern it creates), you just need to sum the outputs of two out-of-phase microphones. This can be implemented in SigmaStudio by subtracting one microphone signal from the other, or inverting one signal and summing both signals in a simple summing (addition) block.
The two omnidirectional mics in this configuration should be closely-spaced. You may also need to apply a low-frequency EQ boost to the signal, as this configuration is less sensitive to low frequency sounds. If you're interested in using our miniature MEMS microphones for this application, you can find more information about them here: http://www.analog.com/en/mems-sensors/mems-microphones/products/index.html
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