Tosser test passed with flying colours mate :)
there are an awful lot of wrong answers to my question, and a very few right ones (for instance: "fucking terrible, any ideas?"), but that's one I've not heard from anyone but our own pet DJ's before.
Does that actually work?
I know that we never had a feedback problem with decks when working with Rich(other half of snss) and George, it never entered my head. Pissed me off at times cos i LOVE alex paterson's patent trick (in my head...ok..i know other dj's do it) of stopping the deck, slamming the bass up and waiting, then sorting it all out JUST before the soundsystem implodes, and I used to try it if left near the decks too long, and it never worked. And one of the tricks they told me was adjusting the cart mounting (and obviously not using jurassic needles with a nice pick furry halo round them to act as a pickup).
Ah well, MUST be true then :)
The single dumbest thing I ever seen done was by a certain nationally known Belfast DJ and his sidekick. they used to drag this completely un-called for sound rig up from Dublin, costing a fortune, and not use half of it. On several occassions when I attended as a wankered dancing mess, the decks were set up on....
brace yourself for this....
unplugged speakers
of exactly the same spec as the ones, plugged in, 3 feet away.

you don't need to be Martin Hannet to work that one out like (if anyone is confused about what I'm on about, find a guitar, or a piano and sing a note to it.....it sings back...sympathetic resonance)FFS some big concert rigs actually have passive speakers in them to get better resonance.
One night I was playing there, me, a couple of totally wasted tubes from college who I refused point blank to play the tunes to before the gig (I even soundchecked with a tune we weren't playing), and a bunch of unreliable and sick machines.
I tried to tell the dj's what was going to happen. No comprehension.
SO, the Dj's pushed their level as hard as it could go before VVVVVVVVVVVMMMMMMMMMMMMMMMMMM happened, and stayed their all night. i came along at 11:30, with no such limit, the engineer [1] just grinned, and let it it ride. I literally BLEW the decks off the stage volume wise...the place went fucking mental instantly I dropped a bass drum in. Good job too cos the tunes were pretty shite TBH.
hey, look, I'm talking bollox again.
[1]remember I said the rig was pointless....they had a 32 channel console for...a stereo line from the dj mixer, 2 mics for a percussion player, and on that night, a stereo pair from me). I'm thinking I'm a twat for looking at something that size for doing 4 friggin bands on for NOOLday :) They also had an engineer, an assistant engineer and a 4 man crew. What was actually needed, was authorization from the house to use the in-house rig, and then 60 bills for 2K of bass bins from the hire shop...next door (more or less)
muppetry!
The engineer had the look of a man who'd had the same conversation as me with the dj's so many times he just didn't give a fucking toss any more, and I do not blame him one bit.