I am getting this humming sound in my 2003 Dodge neon. First I thought that I was getting from my two rear old tires. replaces them and now I have all four new. The humming sound goes up with the speed and it is very low at below 30 miles. It stops at stop light. I have 92000 miles in it. I am planning to change the timing belt soon. Can somebody help me in figuring out this sound?

 

Probably a wheel bearing. Where is the sound humming from? Does the tune change while turning?