also bear in mind that fans are lounder than normal if they cannot get proper airflow happening. this happened in my case as the fan grill was really just a series of punched holes in the rear metal sheet, less than half the air moved by the fan was actually getting out. so i cut out the hole, put on a simple fan grill and it was MUCH quiter.
the fan was no longer struggling to move air.
<b><font color=blue>I prefer to blend into the background, because it's much easier to sneak up on people and disembowel them that way. Arr!</b></font color=blue>