While browsing your activity monitor, I’m sure you must have come across something called ‘coreaudiod’. Did you stop to wonder what it is?
This particular process, coreaudiod, is the daemon that powers Core Audio , the low-level API for sound on macOS.
A daemon is a process that runs in the background of your Mac; you can identify them by the “d” at the end of their names e.g kernel_task, hidd, mdsworker, installd, WindowServer, blued, launchd, dbfseventsd, and many others .
But what is Core Audio? Well, according to Apple’s Developer portal, it handles basically everything about sound on your Mac.
Basically, if sound comes out of your speaker, or is recorded with a microphone, coreaudiod had a part in it. For this reason coreaudiod will take up a little bit of CPU power any time you hear audio through your speakers, or record something using your microphone.
If your sound ever stops working—and you’re completely certain you didn’t do something like mute all audio or change your audio output device —restarting coreaudiod in Activity Monitor should solve the problem in cases where you would otherwise have to restart your computer.