Paul McCartney Live Sound?

[sabreman]

Last evening I went the PM show in DC. The sounds was amazing. In a way almost too amazing. Is there some type of vocal / instrumental enhancement going on? Is he singing over prerecorded tracks? Most of my experience is with lower end acts. EC is about is big time as I get but he doesn't appear to use any type of enhancements. Actually he is very hit or miss sound wise.