DDJ-XP1 question
Can you use it with 3 cdjs or is it meant to be used with only 2 decks
Noone knows yet, but I am hoping the deck switch button also works with CDJ’s.
It does, see Pioneer DJ. Both the SP1 and XP1 can control up to 4 CDJs.
At this point in time it only works with the CDJ-2000NXS2 and CDJ-Tour1, both of which had this enabled via their last firmware update on 12th Sept.
Hopefully Pioneer release an update soon for the XDJ-1000mk2 
SP1 also works on XDJ-1000mk1 and CDJ-900nxs, right?