HI ALL,
I just got the z2300 for the studio and the directions and patch cords are meant to plug into two line sources for stereo as at Line out R & L on the rear of your keyboard.
These are awesome little speakers. I will use them in the motorhome instead of packing those 75 pound (each) or the 55 pound motion sound KS200.
The single stereo plug is for the sound card on the back of your computer.
Bebop