at 30mph loud humm from front tires?
 

On my 06 Cobalt when I get arond 30mph starts sounding like I'm in low gear you can only hear it with windows up the sound stays till I slow below 30mph or I take a left hand curve I have 205/55R16 91

belt shifted?

no started doing it with old tires so I got new ones still the same

Hub bearing is my bet.

If you kind of weave left / right /left / right, does the noise come and go?

this^

aka wheel bearing. just did my friends civic, exact same thing it hummed was so annoying. got a new one, install was simple and cant hear a thing now. if you dont feel comfortable just take it to a shop it shouldnt be more than 200

it only goes away when I make a wide left turn and I had a friend drive past me and I did not hear it outside there is no shimmy I can take my hands off steering weel still goes strate

Well it's easy enough to test. Jack it up, grab the tire at 12 and 6 and see if you feel any play when you push and pull.

Agreed

Just tested and replaced wheel bearings but noise hasn't stopped
 

I have been hearing the same noise. It gets louder when turning to the right and goes away when you turn to the left while driving. Naturally I figured it was a wheel bearing. I put the car on the lift and had some play in the passenger wheel. So I just replaced the bearing today and that wasn't it. The noise is a little quieter now but still present. Now I'm thinking its the bearings on the case of the tranny where the axle comes out. I started the car on the lift and heard exactly where it was coming from. Now what I don't know is how to even begin getting to those casings. Do I have to pull the whole dam axle out?!? I also tried to check the U-joints and when I removed the ring of the U-joint boot, I began to loose some sort of grease/fluid, so I just put it back together. Does anyone know how to help? or has done this before? and doesanyone think i have to open the tranny to press those casings out. I have the part # for them. Please please please someone respond with any info. If i cant do it I'm having a shop do it, but **** Chevy. Last time my brakes had a leak they gave me the car back with a leak still.

Just as everyone else has said it's most likely a wheel bearing.

Yup front hub assembly....take it into the dealer it will be covered under powertrain warranty if your car is still under it