Alison Krauss is my favorite vocalist and with Union Station puts out superb bluegrass music. Unlike many, MANY in country and pop music she does NOT use Auto Tuning software (usually the Antares version is used by pros I think). Tonight she’s on CMT with Vince Gill, another great country performer.
Auto Tuning takes off-key notes and puts them in key. This process is used routinely on recordings and even in many real time performances using high end gear that routes the microphone output through the auto tuner before it goes out the amplifier.
I don’t object to the use of Auto tuning – it’s inevitable – but I wonder if it’s changing the music industry in undesirable ways. For example attractive artists are now more likely to beat out unattractive ones because their pitch problems can be corrected. Why is that a problem? Clearly innovative music is more likely to come from great musicians, not attractive ones, and obviously better musicianship is an asset to the industry.
Joe Duck 
How can you tell she does not use auto tuning?
When you listen to Let Me Touch You For Awhile (on New Favorite), there are a few places where the voices are too plain, too exact not to be artificial.
Tick I forget where I read that but it was an article noting how almost all artists now use it and listed her as an exception. I’d guess they *do* use some form of adjustments to clean up the recording quality and maybe that’s what you noted.