To enable sounds for Calendar notifications on your Mac, click the Apple menu → select System Preferences → click Notifications → select Calendar from the list of apps → click the "Play sound for notifications" box. You can also change the sound that is played from the Sound menu.
Enabling Notification Sounds
Click the Apple menu.
This can be found in the upper-left corner of the screen.
Click System Preferences.
Click Notifications.
If you don’t see this option, click the Show All button at the top of the window.
Click Calendar.
It’s in the sidebar on the left of the window.
Click the “Play sound for notifications” box.
When this box is checked, you’ll hear an alert sound whenever you receive a Calendar notification.
Changing the Notification Sound
Click the Apple menu.
This is located in the upper-left corner. If you are still in the Notifications menu from the previous section, just click Show All at the top of the window and skip down to Step 3.