Any ideas what my 98 chevy malibu is doing theres a weird noise?

Question

i have a 98 chevy malibu and when i drive under 20 miles an hour its fine but upon hitting 25 miles an hr theres as wierd humming noise that sounds like a small humm from somewhere in the car it gets somewhat noiser as the car accelerates but as i decellerate it slows back down to no noise . i was wondering if its something to do with the speed sensor as there is no speedo cable its all electronic on this car . we noticed the noise a week after we got back from virginia beach on a vacation. any ideas

Answer 1

its a wheel bearing.or as on that car its called a hub assembly  

Answer 2

Possible tire going bad. Could be a wheel bearing but normally those get noisier when you trun one way or the other.