I’ve had a look at the back panel of this crossover and it is a bizzare setup as even on Behringers etc you have a TRS for either unbalanced or balanced and XLR for a balanced connection.
the way I am reading this even sounds like chutney joe may have accidentally double wired the same audio output to the same amp and even if he hasn’t that does seem like a recipe for an unwanted hum/ground noise loop.
Add to that a laptop DJ on the same mains supply and a earthed laptop PSU and that might not sound so good, and that is the kind of thing what will trip you up at a event if you aren’t careful…
the cables you need are cheap at CPC | CPC – Over 100, 000 products from one of the worlds leading distributors of electronic and related products. and a lot of them are on special offer at the moment (always worth geting a few spares..)