This is the official Facebook response on using your microphone: https://newsroom.fb.com/news/h/facebook-does-not-use-your-phones-microphone-for-ads-or-news-fee

This is the official Facebook response on using your microphone: https://newsroom.fb.com/news/h/facebook-does-not-use-your-phones-microphone-for-ads-or-news-feed-stories/ https://newsroom.fb.com/news/h/facebook-does-not-use-your-ph... According to that, they do not listen for ads.