Oscillation is a great word to describe the sound the NW mani's make. You can hear that air moving. That's why mine is so loud between the two mods the whine is a combo of the two mods. I get so much compliments at the track that once I get back to the pits usually there are 3 to 4 guys waiting for me to pop the hood. I have lots tell me that my turbo is really loud.