No, you really want to build plywood or MDF boxes for your speakers....And you should attempt to build the boxes the right size for the speakers.

Large woofers need tuned boxes to really make them sound right. So google up some of the free speaker box calc programs and just plug in your speaker specs till you can determine proper box volume.

Go here:http://www.carstereo.com/help/Articles.cfm?id=30

Then keep going till you understand it fully. You can buy cheap Radio Shack speakers and make them sound great if you use your head.

I do sound. I do sound in a big way. I do sound to stadium size. Audio is my thang.

Car audio is easy compared to what I do for fun....but it's always the same basics...speakers need a tuned enclosure or they sound flat.