Oh boy i have a delta 60mm and it is looouuuuud! The thing hits between 7.2k - 7.5k rpm and it is not a puppy! The vibrations are what annoy me and the high pitched whine of the delta though. The db it produces is bearable, just.
Thanks for the post Whip. I can testify that the 92x32 Sanyo Denki fans are an excellent air mover. The thicker well (>25mm) gives them more power with less noise. They are great case fans at 55cfm. I recommend them.