I tried a search, and didn't get anything I could use. I spent too much on the rest and decided to make some of my own. They sound pretty good for the low buck application. Will car audio speakers perform differently? Do I tune the boxes around what the subs will do or the subwoofer output? I took some older, but nice looking, Wharfdale cabinets and am using a 1990ish vintage Kenwood tuner for power. They hit quite well but do distort at the very low frequencies. Popping type noises.... The subs are just $100 car audio ones. I thought maybe a frequency block for the very low or a beter amp than a tuner. For $100, it'll get my by for a year or so.....