My research indicates that the RotoMold seats will significantly reduce sound transfer from a Sub. The thick plastic absorbs a lot of energy as the sound passes through, whereas the Switch Back and fiberglass helm are open to the plywood floor, which actually spreads the sound and adds to the bass performance. Kicker 51MWLE10 and 46CWTB10 remain a significant question, as does the Helm vs. Swingback.