I have a 2013 Versa SV sedan. It has been a good car. Around 65-70,000 miles it started to hum in the front end. it was quiet and faint, but I could tell that it was there. I got the tires rotated and balanced then and nothing seemed to change. I figured it was the front left wheel bearing, so bought a cheap one of amazon and put it in. The hum didn't change but the front end was noticeably worse, so I bought a Timken bearing and just this week had that put in. That again didn't change the hum, but the front end was smoother. (Never will buy cheap China bearings ever again). Since I first heard the hum, it has gotten louder. The hum first becomes noticeable around 35-40mph and gets louder to a drone that is very noticeable and noisy. I havent gotten an alignment since changing the bearing, or had the tires rotated (even though that didnt help before) Any ideas on what would be causing this?