I agree with the other three people that dynomat is one thing you should do as well as getting a subwoffer in the back. But as it seems to me you shouldn't be expecting to get low range bass out of the 4x6 or 6x9. That will lead to distortion as well as possible leading to blowing the speakers. I would just get good midrange and high's upfront with a little balance of low frequecy's and just use the sub in the back for the really low freq.'s-- I hope everyone agrees with me and that i am right?----
chris-