I think I've got most of it, but some things need to be confirmed. I'm about to hand over some cash for a used Behringer 4-bus mixer, the MX2642, so I was wondering about..

Aux sends: The MX2642 has 6, so does this mean I can have 3 "true stereo" fx units connected into it, in an aux send/return loop? Maybe more? How?

I have a suspicion it is possible to connect fx units to the channel strip inputs. How or with what do I re-route the fx to the..say channels next to those of the fx unit? Will the faders on the fx channel strips cause feedback?

What exactly do the busses do? Apart from having their own volume-fader, do they just separate the fx or what?

If anyone has links to where I can read about the workings of larger desks, I'd appreciate it. I've been blissfully spared from these things since my old mixer only had 2 aux sends. Thanks.

-tek