Why is my macbook pro making dialup sounds?

Hi perpetual77

Sounds mysterious! Hmmm.

Do you have an old modem connected to your MacBook Pro?

(At least one Australian National Broadband Network provider still makes use of them for users to have a free website space.)

Could it be a mp3 or wav audio file of the original sound a modem made when converting digital to analog?

Maybe something is blocking your speakers ?

Could it be a noisy fan?

There's an older discussion on a noisy MacBook Pro speaker that may be helpful.

https://discussions.apple.com/thread/251164824

All the best.

There's a recent discussion on screeching sound, with a suggestion on tracking down the source.

https://discussions.apple.com/thread/252451254