That was my thinking when people told me the M60's were better than the M22's as well. It's kind of hard to explain. The M60's just have a fuller sound to them. Even without the sub, they're amazing. You can TOTALLY get away with using the M60's without a sub. (especially for music), but a sub just adds a bit more depth.
Like I said, when listening to music, I have the sub crossed over at 40hz...that's really low. I'm only using it to flesh out the really lower end.
I had a fellow boarder over a little while back and we listened to a bunch of music sans sub because he'd be using them in his home without one. I was VERY impressed with what they could do without a sub. He was too - he had to ask more than once if the sub was turned off.
(btw...he now owns a pair of M60's himself!)
