Well this is one of them have to be hear and hear it to fully understand but I will do my best to explain. Hopefully someone here can offer some pointers.
About 7K miles ago I have 4.88s, ARB lockers, and a Truss system installed. Now at about 15-20 miles per hour I start getting a roaring noise first thought was maybe a wheel bearing but they checked out to appear ok. I did the old jack up one side, push pull test on the 16 and 6 o'clock position of the wheel. The noise tappers off a little but at about 50-55 it comes back and seems louder, if you let off the throttle the noise goes away but the instant you reapply throttle the noise comes back which leads me to think it is not a bearing. Even when coasting downhill the noise is not there till throttle is reapplied.
About 3K miles ago I did put in a K&N filter, I myself am not really a fan of K&N but that was all the store had and I was out of town having no related issues.
Like I said without being here to ride in it and experience/hear it a proper diagnose is almost impossible. But if you have any input please speak up.