Diffusers are great - I just got one for mine and its a fairly big bong (18 inches or so high) with a good sized internal bowl.

It used to make a LOT of noise, I live on a quiet street and with the window open you could hear the bubbling outside my place!

Now I have a diffuser it hits smoother and is more quiet too If they are cheap buy 2 - you never know when you are going to break it again.