How can I add a beep to ZSH's prompt?

I had this problem a while ago and found a working solution although it does not quite make a beep.

sudo apt-get install espeak
espeak "job complete"

Ok, figured it out. I added:

%{$(echo "\a")%} 

Maybe not the prettiest (there's gotta be a way simply to output an escape code correctly) but it works.