Originally Posted by E90Company
Odd thing is my sound goes away after I get past the low RPM band. I would think if it's actually the compressor touching the housing it would stay constant, and at the same volume.
Your compressor wheels aren't touching anything. That's the dentist drill noise, not the siren. If that were the case, you'd know you had a very serious problem. And as you said, the noise wouldn't go away. You have a very, very common noise. A lot of people don't even know the car isn't "supposed" to sound like that. Like I've told you about 5 times now, relax and go drive your car!