This a custom designed, fabricated, calibrated and built home theater I did myself in my basement.

The exterior walls and ceiling are not in contact with the house foundation walls or ceiling. For design, environment and acoustic reasons there is an 8" gap on 2 walls and ceiling to the house structure and wide open on the other two walls. Adjacent to the custom broadband absorbers are some custom built bass traps I made and started testing...not bad for things I had just lying around the house collecting dust.