WOW! Thanks a ton I was actually considering building a silencer box if nothing worked. Im going to take your advice. An try to build a strong silencer box out of wood or something??? What'd you use to build yours? An the inline fan still fit on the carbon filter? much needed advice thanks before I go through the trouble. I will check out the sts fan see what your talking about. My tent is a 2 x 2 x 3.
I used 1/2" MDF for the box. Lined the box with carpet. Packed tight round the out side of the fan with old sofa cushion foam. Nice and dense that stuff. I also hang my box from my loft rafters so it touches nothing, you will be surprised at how much the vibration of the fan carry through the ceiling.