Roaring sound on high RPM

[boneca]

2011,3.5i,50K miles.
While getting on highway this afternoon I noticed car making louder than usual roaring sound coming probably from engine compartment or underneath. When driving in the city or idle I almost can't hear a difference, maybe a bit but not much. Should I be concerned and give a call to a dealer? What could cause this? I assume this is not exhaust as there is no loud sound on idle or start, could it be gasket or else?

Thanks guys in advance!

[Bklynjoker]

If u don't know we do have active exhausts. At around 3000/3500 rpm the Right side exhaust opens up which does give a aggressive sound. Normal drivng only the left is active

[boneca]

Originally Posted by Bklynjoker

If u don't know we do have active exhausts. At around 3000/3500 rpm the Right side exhaust opens up which does give a aggressive sound. Normal drivng only the left is active

Thanks Bklynjoker, I know about active exhaust and obviously it's not my first year owning X5 so I kinda know how it's supposed to sounds.
Anyway I had a chance to stop by at service today and speak with one of the reps, he came out and listened to the sound, from what he said it might be either an exhaust flap or issue with exhaust baffle. Nothing that needs immediate attention but something that needs to be looked at. The exhaust flap can be somewhat inexpensive fix where the baffle can be expensive as it will require replacing the exhaust.
I guess I will bring my car for appointment one of this days and then I'll know for sure.
Thanks for reading!