If you're the sort of person not to use a pre-packaged desktop environment, you can use mako as your notofication daemon and get the same effect by adding on

If you're the sort of person not to use a pre-packaged desktop environment, you can use mako as your notofication daemon and get the same effect by adding on-notify=exec play /usr/share/sounds/freedesktop/stereo/complete.oga or the equivalent to your config.