What is causing my road noise?

I have a 2000 Hyundai Sonata V6 GLS. When driving, I hear a constant hum. It gets louder with speed. When I turn right, the noise stops completely. I think it gets worse when I turn left, it's hard to tell. And when I stop, I smell burnt rubber. I jacked the car up and checked for play in both front wheels to see if it were wheel bearings, and there wasn't any. I took it to Monroe Muffler and Tires and they couldn't see anything wrong. I also recently had them check all my wheel bearings from previous road noise (only the rear left was bad and I changed it myself.) I noticed this new noise Immediately after the change, but probably because it was so loud before. If you have any suggestions, please let me know how to tell if it is a bad part if possible. Thank much.|||could be tyre noise if bearings ok