I might have to look into getting a few of those.

Do you know of a good sound absorbing insulation board? My miners are on a 3' x 72" tall shelving unit that you can get a Menards.  What I am thinking about using is 1-1/2" foam board. I would put a piece on each side and one on the front of the shelf. The front piece would have a hole in front of each miner that the ducting can come through. Now the back is close to the concrete wall in my basement. I thought if I space the shelve about 6" from the wall and put a piece of that same foam board on the concrete behind it that I would still get some good intake air flow and the board would help knock down the sound. This is all in a room in my basement. I wanted to leave the back open also for ease of access.