Got this from Tirerack.com
I'd go to whoever you bought them from and see what they can do for you.

 

I have a set too and they are quiet... You got some weird tires or are hearing something other than the tires...like a bearing of something.

 

My Duratrac's are very quiet on the road. I would say you have something else causing the noise or the tires have some sort of defect.

 

i have them, so so quite. fix whatever is wrong with your jeep and hope someone will replace them under warranty because whatever your issue is it has prob ruined them.

 

Found the offending tire. I only found it by accident I was rotating and looking at the tread looked normal than the last tire I was rolling up to the jeep when I felt something funny and looked down at the center of the tread and there was a dip in the center tread blocks not noticeable from the side. My tire guy said internal failure. I still find these tires a little more noisey than I like. My other xj has 33 TAs km2 and there quieter. Glad I found the offensive tire as I was not looking forward to changing the muffler or wheel bearings.

 

I'm not sure where you'll find a quieter tire. I bet yours are still wearing oddly.

I find it hard to believe a set of KM2's were quieter. Not calling you a liar, just that something isn't right with that.