So the box is 33 X 25 X 15.75. Inner dimensions are 31.5 X 23.5 X 13.5.
What I'm gonna do is run a 3/8 threaded steel rod lengthwise and along the width as well from the center of the panels. I'm gonna use washers, lock nuts, and bolts on both sides of the mdf panels to secure the rod and prevent air leakage. Considering adding sound deadening around the holes as well to ensure a tight, vibration free seal. Top to bottom I'm adding a brace at each 11 inch interval of 2x2x13.5 inch hardwood. This should pretty much remove almost all vibration and fortify the box for a long time. There will be a nut on the outside of each box face so it'll look ugly but should be totally functional. Any constructive feedback on the effectiveness of this plan?