I'm aware this can be done via cross over ethernet cable and using LoopBE or other commerically available midi progs for the PC laptop.

Or via an adhoc wifi network.

But...

My friend uses 2x X1's with an A8 and I have the option of a S4. Both the A8 and the S4 have midi ports. Can I use midi cables between them and will this have the same affect?