I definitely got MDF ***** though, will have to take it more seriously next time, cut pieces wrong alot and spent a ton of time screwing off with bad cuts...
My first box was an old speaker box made out of 1/8th inch particle board. The original speakers were a 3" woofer/mid and a 2" tweet/mid.
I hacked it up and put a 10" sub in it, filled up the gaps with cardboard and rope caulk, and stuffed the box with socks. When it hit it would "crawl" along the floor of my room until the wires would pull out of it, lol.