Anti howling - Microphone

Hello Butpt,

There are many posts on the forum discussing this problem. There are a few techniques to do this. The ADAU1701 is one of our smaller DSPs which limits what can be done.

This post discusses shotting off the mic when not in use.

(+) How to eliminate feedback in ADAU1701 - Q&A - SigmaDSP Processors & SigmaStudio Dev. Tool - EngineerZone (analog.com)

One method is to pitch shift the signal slightly that is going to the speaker output so it is different from the last time the microphone picked it up. This can work and I have seen people use a chorus for this as well.

This post has some info but it also shows that pitch shifting is not perfect. It might work for your situation but might not.

(+) Acoustic feedback Cancellation Software Sample Code - Q&A - Audio - EngineerZone (analog.com)

This post is an interesting approach.

(+) Variable band-stop / notch filters - Q&A - SigmaDSP Processors & SigmaStudio Dev. Tool - EngineerZone (analog.com)

This post discusses changing to another more powerful DSP.

(+) Remove audio feedback with ad1940(dsp) - Q&A - SigmaDSP Processors & SigmaStudio Dev. Tool - EngineerZone (analog.com)

This should get you started...

Dave T

Hi Dave,
Thank for your information