It's not completely straightforward as the Audiobox output is professional level balanced and the Logitech speakers are domestic level unbalanced. Even if you take an unbalanced output from the Audiobox it could well overload the inputs of the speaker system.

Commercial balanced-to-unbalanced converters are expensive, so are you handy with soldering? I could give you the diagram of a simple circuit using only connectors and resistors that you could wire up and see if it works adequately for you.

Logitech z-2300 are a tuff, I once use it in my car as a sub (without the satelite speakers) with a power inverter... Boswell is right about the balanced signal.
But, I wouldn't be scared to use a adapter 2 x 1/4in mono to 1/8in female. As long as you don't crank up the audiobox output higher than -10db