I have 2 years, have plenty of membranes Mount diffrent in just to see, and the basic sound of this box is loaded hot and trs in the low regardless of the install hp. It rsons also not bad, in the good way, despite the original cotton. It must be said that it is well done, with real plywood so lightweight, and more than rsons mdf, etc. agglomr.
I think that kind of hp g75t celestion v30 and are best suited for this box, by their curves (mountain and valley for celestion box) respectively.
Eminence Legend 122 Alnico: bcp too serious, acute too low. PA neutral membranes: dj best sounding guitar right away, good for modlisateurs line6 cube style etc..
Origin: nice, a bit dark but frankly, when even good hp Installed also surprising.
Eminence Kappa 12: trs equilibrated but given the weight box is not suitable, too lightweight and not reinforced. Not enough highs either but they are good Kappa ...
In short, trs good quality-price ratio, but take the v30 to be little that has prssr quelquesoit you like the amp.