Here is a video of two bands playing LIVE at the same time:
I was wrong.
Motorhead used to play similar gigs.
They would set up at one end of a large hall, and another band would set up at the other end. Both bands would play. If you stood in the middle you'd get brain screwed, but if you stood nearer to one band than the other, you'd get blasted.
I've found no evidence to suggest this actually happened.
Who did they play with?
Seemed that it was more about lager than the music, though; and what IS it with that nonce flapping about in the front row wearing a heavy coat?? Is it THAT cold in Colchester in April?? Interesting concept this 2-band thing- you kind of get the same effect at Vans Warped Tour with multiple bands playing, but not in such close proximity.
and the sound man forgets to turn the backing music down.
when I'm listening to something on itunes and then accidentally click on some autoplay ad (I'm looking at you evil sean adams).