I have been using the single 15" slanted array for awhile and its a beast! I love it best cab I think out there the new Genzler line I mean, only issue is sometimes having a single 15" I had to push the cab harder, I just tried out a second 15" on top and wow!! I didnt need volume at all but fx like envelope filter, phasers were not cutting threw mix at band levels. I just literally tried the second cab last night and wow! not only was I able to turn down more, it made my sound so full and the fx cut threw like butter. I am trying to decide if the 12 slanted would be just as good but Ill prob go with the 15" just cause how good they looked stacked lol, but the sound was utterly amazing. I didnt think the 15" would be able to pickup so much like they do, great speakers and with the Magellan head its an amazing combo. I tried just about every other cab head combo out the and Genzler stole my heart from first plug in. I actually committed to it before even looking at tag. The mesa subway was close but I played that threw a 4x10 and I still liked the Genzler head and single 15" over that one, like I said just lack of having speakers is hard with fx, but if you are just a plug in and go guy the 15" slanted array will do you wonders man, truly.