Change FaceTime ringtones on Mac
You can set a default ringtone for all incoming FaceTime calls on your Mac.
In the FaceTime app on your Mac, choose FaceTime > Preferences, then click Settings.
Click the Ringtone pop-up menu, then choose a new ringtone.
When you select a new ringtone or text tone, a preview of it plays unless your Mac is muted.
To change the ringtone or text tone for a specific caller, edit the caller’s contact card in Contacts. See Update contact information.