Heard a pair of Titan 48s stacked on their sides yesterday in a parking lot - stunningly loud and clear - louder than anything I've been near (4-2x15s) - builder/operator had built them with 3015LFs.
(During Sacramento CIM race 12/7/14)
No more convincing needed for me.
Note that he did not have them working in conjunction with an adjacent wall behind and wasn't using a "V" connector, they were merely just stacked.
T 48 witness
Re: T 48 witness
Nice