as technically astute as RW370 claims to be, I felt the urge to post this reply...
Just so you know:
I am a stagehand in Charlotte, NC where they spent the week before the Greensboro show rehearsing and preparing for the tour.
I am, by no means, a Van Halen fan. I would like little more than to find fault, but I find myself in the position of defending them here.
I happen to know for a fact that there is a live keyboard player just offstage where he cannot be seen. As strange as that sounds, it is done from time to time by guitar-driven bands that do not want to let people see something so inhuman as a synthesizer. (Or for some random other reason, there is just no telling.)
I will say again that I was not at the Greensboro show, but I heard the full set at least 6 times in the week before it. Each and every time, they tore through numbers with remarkable skill which impressed me, despite my lack of fondness for their music.
If you wish to attack Dave and his giant inflatable microphone or anything else of the sort, have at it, but trying to do a critical analysis of the tonal qualities of a band based on a cellphone video is pointless.