Rumbling noise coming from car

Hi, I have a 2001 Jetta TDI and while driving on the highway yesterday the car started making a rumbling noise. I don't think its an exhaust issue because the sound doesn't change with the car's rpm and it sounds normal while idling. The sound only picks up when the car gains speed. I jacked the car up today and checked each of the tires for anything stuck in them but found nothing. The wheels seem to spin smooth and there doesn't seem to be any play in them. My back tires are kind of worn out but it don't know if its possible that they would be making the noise because of that. The car seems to be running fine other than the noise issue. Has anyone here experienced anything similar or have any ideas what the issue could be? I know it's difficult to say based on the description but any suggestions would help. Hoping the problem is more of a quick fix than a serious one. Thanks

Bad wheel bearing?

That's what I'm thinking. I'm going to get a garage to look at it later in the week. I'm hoping that's all it is.

Take it for a drive with the windows down and see if you can narrow down where it's coming from. Do you hear it on one particular side? Louder in the front vs. in the back? Does the sound change when you load the steering one way or the other?

My daughters Golf was rumbling like yours and while it did have a wheel bearing going, the real culprit was a leaking flex pipe and sleeve clamp.

Could be an inner CV Joint as well.

Had a very similar sound thought it was an exhaust leak until I shut the engine off on the highway at speed & it didn't go away. It was a rear wheel bearing making the noise.

Could be a broken tire belt, that happened to me a few times, feel the inside of the tire edge and be aware of potential metal wires poking through the side wall, they are sharp!

This is getting to be entertaining. All the things it "could be". Any of these marked off your list yet mts? Use the process of elimination... You have to be at least half way there!

Had the car in the garage today and it was a wheel bearing causing the noise. I also have to get the hub replaced as well. He had to order the hub in so it won't get replaced until Monday. Hoping that fixes everything.