I have those too - have had them for about 1,000 miles.
Back when I was researching tires on tirerack, I read some reviews that said they were loud too. I played the odds, bought the tires and really haven't noticed more noise over the BFG's that came with the car - I actually think they could be slighly quieter if anything. Can't really say I've noticed any rumble sound at any speed thus far.