A Short Stack is...

a) Made up of wires
b) There are 6 going from the player to the ICBM, and another 6 from the ICBM, 12 total.
c) The wires only run a short length.


Second guess, same as first but:

b) Only 6 wires


Third guess (!), same as first but:

b) 6 from the player and 7 out from the ICBM - the extra supporting the dual sub configuration, 13 total.

Alternatively, a Short Stack is:

a) made of CDs
b) there are several in the stack
c) the stack is short as it contains all the classic Outlaw #1 hits! :-)

Fun fun fun!