Learning the AWD typical noises

So like most enthusiasts, I try to be in tune with my car and therefore I consider every noise it makes. First off, my rs5 runs wonderfully and I’ve recently changed the oil, so she’s definitely healthy. I’m not used to having extra differentials in the middle and front of the car so some noises up at the front are definitely foreign to me. After a nice 2 hour trip out of town I decided to check under the car and was concerned about the natural noise my car seems to make at idle which sounds not unlike a blender chopping up ice. Is that honesty normal? Obviously my description isn’t the best but it definitely doesn’t sound like any other engine from underneath that I’ve ever heard. Please, someone rest my fears.

This is no immediate help, but how do you check under the car when you hear the noise, so that we can try reproducing.