Owned both.
Real world with generally used drivers.
T18 45hz and stop.
Cubo 40hz and a little bit below.
SOunds like nothing, but in todays dubstep world you can hear that last bit.
Also you need to couple T18's to get lowish, not Cubo.
T18 is louder though, at full pelt with Bhangra/Techno they batter it out..
All with magnet out, correct driver phase.
I have four RCF loded T18's here. Up for grabs maybe...