Just add a 4" thick concrete slab under my Servo-15. I always tought it was a little strange to put a slab in my HT, and was hesitating. But what a difference! Faster bass, tighter, bender blending. Quite a difference. It's like I own a new sub! The sub was moving around on my woodfloors, but not anymore with the slab. I was hearing a transfo vibration. It's gone. All this for 8$ cdn. Just put a thin piece of carpet around, and it's WAF-proof.