Building a box is easy, you just need to use (at least) 3/4" MDF that you can pick up from Home Depot, Menards, Lowes, etc. hardware store. Just make sure when you calculate the dimensions, add the width of the MDF also. Also, sealing it up properly is a necessity, since you don't want any leakage of air. If you plan on using it for home, you will definitely need a separate amp that is capable of at least 4-ohm stable, depending on how the subs are wired up.