I have a small cabinet loaded with a 12" speaker that I bought used. I have no idea who the maker is. It looks well construted although homemade. I was using it as an extension cabinet for my Gkmb150e combo. This put 75watts into it and it worked well but I'm thinking about pumping some more watts into it- like around 300 or so. What kind of speaker would work in a small box like this? I know I won't get a ton of bass from this thing but I want something that won't fart out when I boost the bass a little. I don't know much at all about speaker cab design so I need some help. Heres what the cab looks like internal dimensions 16" x 13" x 11" There are two square 2.5" ports that extend 3.5" back into the cab. It has some internal bracing and foam insulation. Thanks alot for any help!