Or an even better way is for promoters to sort thier heads out and stop being dumb cunts. An easy solution to most jumping problems is to use a pair of shure m44-7's. And the best way to stop feedback is to move the decks away from the speakers.
Mind you, they must think it easier to make some makeshift bolox of an oil-rig to sit your decks on, then put some stanton 500's on the decks.
The mind boggles...