Whoaaa... They really have 8 speakers in the thing?
Does it really feel like surround sound?
Yes, there are four separate speakers inside each earcup and it really IS surround sound. The headset has three 3.5mm plugs, one each for for Front, Center/Subwoofer, and Surround. These get plugged into a 5.1 (or better) sound card. The small inline amp has a low-pass filter that grabs the low-frequency sound from all three inputs and re-routes that to the subwoofers. There is a USB plug that is used only for power. No sound signal travels via USB. Your computer's main CPU is not really in the loop, depending upon just how well your sound card off-loads sound processing duties.
Check out the little sales pitch video on the Turtle Beach site. The guy is a bit faux-cool and a bit breathless in his descriptions, but it's an interesting video nonetheless.