I just picked up a 2005 S4 with 15,500miles and when I bought it I noticed a slight whoming noise coming from the front wheels. Took the car to my local dealer for service and requested that they rotate and balance the tires hoping that it would eliminate the noise problem and asked if they could look into the problem. (Let me point something out, before I took the car to the dealer the noise was constant at any speed sometimes a little louder at lower speeds but nothing special, noise level was barebel.) Back to the point, the dealer looked into the problem rotated and balance the tires, they told me that the noise was coming from the back and the tires that they put in the front of the car need replacing. Now the noise is louder (unbarabel) and I don't think it has anything to do with the tires, they look fearly new. Something else to point out the right side of the car has a fair amount of parking scraths on the rims apperently the guy didn't know how to park.

Could it be a bearing problem?

 

i dunno im not to familiar with the 05 s4 but it soiunds like a bearing or caliper ...but either way it's a 05 s4??? you dont have a full warranty on that????bring it back to the dealer and say i do not want this back until that noise is gone..those cars come with atleast a 60,000 mile warranty and can be extended..so i would definitely bring it to the dealer and tell them what's up...and i think thatthey will fix it under your warranty ..i suggest just bring it to the shop and find outwhat it is before it gets any worse and makes something else break...

 

It's hard tell what it is.

But some tires as they wear can make a wining noise. Unless you remove the tire from the car & look at it,
it's hard to tell how much tread is left. While they look good on the outside, the inside tread might be gone.
Or simple you can have a rock in the tread.

My other thoughts are a wheel bearing, but they mostly make noise when the car is turning. Or something
stuck in the brake pad, or a sticking caliper. If the caliper is sticking that rotor will heat up a lot, just putting your hand
near the rotor you can feel the heat. If something is stuck in the pad, it will wear a grove on the rotor, but you would
have to look on both sides of the rotors to make sure.

If you don't wrench your own car, any good shop should be able to find out what the problem is.

 

I will put my money on Bent Rims - you can feel the whoming noise from around 15-35 mph real good. I had to replace all four last month. The stock Rims are pretty soft and will bend easy on pot holes. You can get them fixed for about $160 a pop.
I justpicked updifferent rims.