They sound good and hit hard. Connected to a 4000W class D SSL amp.I have noticed a slight burning electronics smell when listening to heavy bass tracks turned up high. Don’t really know what it is but its coming from the sub. The last sub i had in the box had no issues.Update12-26-14Still work like the day I bought them which is a little surprising because of all the abuse I put them through. Looking forward to buying more for a new setup.