I don't use talkback but I did fix the problem!If turning off the talkback makes the squeal go away, what you're really hearing is what audio pros call "howl", or acoustic feedback.
Moving the mike farther from the speaker sometimes fixes this. Consider that if the mike can hear the talkback audio, you'll get acoustic feedback.
Or turn off the talkback.
And if you still have this squeal with the talkback turned off, it's a different problem.
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