I built a ported box that is 85Liter tuned to around 21 hz and I'm not impressed. It bottoms very quickly, especially with stuff like the beginning of Toy Story 2. Did I do something wrong? I have it powered by a 250 watt PE amp. I heard this really loud scratching sound once. Just wanted to add that I don't necessarily think it's the driver, but probably something I did as it seems that lots of people are having great luck with it. I do think that one will be enough as I tweak this one or build a new box, so am selling the other one I picked up for the normal $40 plus shipping. Out.