If your case doesn't have a speaker, its no problem to add your own. Rob one from an old 'throw-away' comp and you'll have the correct header. If not, rob one from a dead pocket radio or tape player and splice in a header from your parts box. You should be able to mount it inside your case and out of the way with hot glue or silicone on the back (magnet side) of the speaker - the cone would face inside the case. Be careful where you mount it so that if it came loose, it wouldn't damage anything if it came loose and fell............