2001 Other Oldsmobile Models Odd whirring noise

Noises problem
2001 Other Oldsmobile Models 6 cyl Front Wheel Drive Automatic

Just today, our 2001 Intrigue started producing an odd "whirring/vibration" noise.

It seems to come from the front of the car, almost from within the engine compartment, but apparently only audible while in the car itself, and not from the outside. It is only heard while driving. I've placed the car in park and neutral, and revved the engine but heard nothing like I do when driving it.

It rises in pitch as the speed increases, but not with the RPM of the engine, and is a low vibration at lower speeds. It does not begin until ~20mph. A vibration can be felt through the brake pedal at the lower speeds.

I noticed that it almost disappears when making left turns at lower speeds when it is usually heard, i.E. 20-25mph. It is still heard though when making right turns at these same speeds.

Engine performance does not seem to be affected, pickup, etc.

At first I thought that it might be something stuck somewhere under the engine or wheel well that was vibrating in the wind as we picked up speed, but did not find anything that would cause this.

Any ideas?