This is actually a relatively easy task. All that's necessary is going
into the wires from one of your turntables (doesn't matter which one, but
only one!) and reversing the connection between high and low. Then, go
play doubles. The closer you get them to perfectly synched, the more
phase cancellations you will hear.
Of course, it's usually easier just to slightly de-phase doubles, and then
re-phase them to drop it back in, but what fun is that when you can go cut
some wire?? =)
Josh Landau
WCBN-FM 88.3, ann arbor, mi