This may be old news or some of you may have done it already but I gave something a try today. I got to thinking about how a flared port is so much quieter than a regular port due to the smooth radius. So why not add a flare to my cooling fan to cut down some noise. What I'm using is a 4" brushless case fan from Radio Shack. By it's self it is very annoying it makes quite a bit of noise. So out to the garage I went. All I did was cut two pieces of 6"by6"by3/4" MDF,than cut a circle in them to just slightly larger than the diameter of the inside of the fan case. Than I used a 3/4" round over bit to flare both pieces of wood. After that was done I took them & put one on each side of the fan & screwed it together. I couldn't believe the difference it makes compared to before now you can hardly hear the thing at all,I bet it cut the noise down to almost half what it was. Before I could very easily hear the fan across the room in my seat about 12 feet away, now you don't hear it until your about 3to4 feet from it. Just thought I'd share it with some of you,if you never given it a try it's very well worth the little time it takes to do it.