Arfan,
That sounds like an American built unit (there is also a manufacturing facility in Europe). If it is, then an option exists to reduce compressor noise / hail guard, it is called option 14.
It could also have the Motormaster III low ambient kit fitted, which will vary the speed of the lead fan.
If you need prices and details, contact your local Carrier represenative, as I am based in the UK.
Cheers,
Cooky.