Subaru Repair: Whirring or winding noise in a 1997 Subaru Legacy Sedan?, formula 1 car, wheel bearing

Question
QUESTION: My Suba started to make constant noise, especially on higher speed (>20 MPH). The noise is like a winding of a heavy dynamo, some of my friends said it actually sounded like the engine of a sport car/Formula 1 car, but relative to the speed, not RPM. The noise is loud enough that I can't hear the smooth engine sound anymore, coming from the front, I think. The faster the car goes, the higher the pitch and also the louder the noise. The winding noise also become louder slightly when I accelerate, become softer slightly when I decelerate or coasting, but generally the noise is persistent and constant. There are no other sounds other than this. Driving is good and smooth, transmission (automatic) shift smoothly. The noise also does not relate to the steering (the bearing), as the noise stays constant regardless of steering wheel rotation. No noise is produced during parking/idle, or high idle RPM. Power is not compromised, zippy like always. What's happening with my Suba???

Thanks before.

ANSWER: Could be a few different things. i would take it somewhere and have it checked.It could be brakes, wheel bearing or even just the tires.

---------- FOLLOW-UP ----------

QUESTION: Thanks for your answer.  I have an additional information:

While car is going about 40 MPH on a straight slope down the hill, I tried putting the transmission to neutral and turning engine off.  The winding noise stopped as soon as I turn the engine off.  Then just after I restart the engine, still in neutral, the noise came back for 3 seconds, then gone.  Finally, the noise came back only after I put the transmission back to Drive.  These were all done with the car moving around 40 MPH.  Can you tell me anything about this?

Thanks again.

Answer
Now I am confused, byt turning off the engine and noise goes away, now it sound like it has something to with the engine, but when you restart it and it comes and goes after 3 seconds, but returns in gear, now leads to something with transmission. It could very well be something loose that is rattling or making noise at certain RPM's Most noise are like pitch forks, they need a specific shake or movement to make the noise. I would definetly take it to someone who can drive it and listen themselves. This sounds like something that won't be able to be fixed with hearing or seeing it in person. Sorry wish I had more info for you.