10 12's in my bed

Finally getting to work on my truck again. Have 10 12" alpine type r's and 5 infinity amps to install. I already have the back wall cut out and such so time to build the boxes. Had my local shop design them, doing them firing down with the ports going into the cab. Kind of worried about the bed floor rattling so I think I am going to spray on bedliner and then bolt a sheet of mdf to the floor then put the box on top of it. We tried to get them to fire a different direction but there just isn't room to do it and get the ports facing into the cab. Any thoughts?

Hoping to get started on it tonight. Finally warming up outside and the snow is melting so getting excited to get her on the road again.

I had used carpet padding under my box, then used Dynamat on the underside of the floor, and squares on the inner walls of the bed sides

Were yours firing down? Never thought about the carpet padding, cant hurt nothing and is cheap. If the simple things wont work, I will pull the bed off flip it over and have the bottom and inside line x'd. I used to know a guy who had to put 4" of concrete on his floor boards of his car to keep it from rattling and keep the sound in. It was a full spl car though. And insanely loud, would make your chest compress and not be able to breathe inside of it.

Mine weren't firing down, but maybe if you lined the bottom of the box with Dynamat, between the box and carpet, it would help retain the sound vs. it being absorbed by the carpet. I had the box bolted to the floor, the sound deadening I had on the under side of the floor stopped any rattles from the bolts. I had also water sealed the box, and seam sealed the small gap at the bottom of the box where it met the floor to keep water from getting soaked up by the carpet and warping the box. Years later when I removed the box, there was no evidence of water leaks. I've done the concrete trick before, too much damn trouble. We had done it on a ranger with a walk through, and twenty four 12's. That was back in the day though lol