Friend has a pair of rather large Soundlab speakers (PA-System style) with 15" Subs. Cost him £250 (Including amp). He's looking at upgrading and is quite good at building things. He's looking to build a set of large speakers with larger sound. Any advice on cabinet design? Speaker sizes? - two 12's per cabinet, or 1x 15?, mids, horns, tweeters Thickness MDF? How-many-way crossovers? Each cabinet can be up to 5ft tall. He mixes mostly Hard Dance & electronic if that helps Dan.