"The thing about the four of us is we hear very different things and see very different things," he tells E! News. "And for every time we could react to the same thing, there were definitely times we thought that a person was completely insane."
Throughout the multi-city auditions, Keith has heard hundreds of amazing singers and a few stand out in his mind. "There were guys that came out and sang, and you never would have expected the voice from them," the country star recalls.
The singer-songwriter says the best part of his new gig has been discovering new talent all across the country. "I love that we went into all these towns and heard so many people," he notes. "It's going to be hard to get to Hollywood week and let so many people go."
In addition to appearing on "Idol," Keith is preparing for his 2013 tour, which will kick off in Australia in January. Little Big Town and Justin Lynch will serve as opening acts when the tour makes its way to North America, beginning in July. Keep track of Keith's concert schedule here.
Keith's debut as a judge on "American Idol" will air Jan. 16 at 8:00 PM ET on FOX.