The only time I think I heard a wolves howl was 3 years ago when we were hunting SW of Republic down by Swan Lake. My wife and I were set up on a nice hill side for the evening hunt. We were just about to get up and head back to camp when we heard some coyotes yipping in the draw below us. She was kinda freaked out by it but I told her to hold on and lets listen and see if we could locate them. This went on for about 10min and it was almost dark at this point when in the distance you would hear a lone howl. They coyotes shut up and it was dead silence.
At this point, my wife is like

and was ready to get out of Dodge. I can honestly say I was feeling the hair on the back of my neck. I did record some of it, I will have to see if I can find it tonight.