I have found when you have an iso-cab such as the Grendal piece of crap that I had many years ago, it would sound boxy no matter what speaker I put in there. When I went to a friends place, he has what Steve has....which is an iso-box. I found with the full 4x12 cab inside that box that it sounded much better and didn't have the issues that the cab had. While the principle of the boxes are similar, I have found that the sounds are different.