I have a Sunn SPL 8028 that I picked up on the super cheap. This monster has two seperate chambers that contain 12" and 18" speaker respectively. I knew I was taking a risk on this thing when I bought it because the original speakers were replaced, but the new ones are simply awful. I'd rather not toss the cab given that it, in terms of size and offerings, has exactly what I want, so I'm turning to the gurus on here for assistance in regards to what I should plug in. I did internal measurements today. 12" Speaker depth: 13.5" height: 18" width: 22" 18" Speaker depth: 15.5" height: 19.5" width: 21" slant: 23" Slant is obviously the odd portion of the equation. The bottom chamber is tilted back, putting the 18" at an angle towards the ear. The slant measurement refers to the length of the tilted side from the interior, as shown in this poorly taken camera phone shot: There is a port of sorts that runs above the 18" chamber from end to end; basically, it consists of a 1.5" slot above the top of the slanted wall. Tone wise, I want something that can retain clairity while being attacked with high volume and large levels of distortion. I will be using a Sunn 300T as my amplification, and if at all possible I'd like this cab to render my Ampeg to the sidelines. I appologize for dropping this on your laps, but I honestly know nothing about replacement speakers and I figured I'd turn to the experts. Thanks for your time, and let me know if you need any further information.