Alain,

You have two ways to connect your keyboard to 2 Roland KC-300s in stereo:

1. Connect your keyboard's L & R outs to the L & R of, say, channel 1 on the first KC-300 (assuming this one is your left speaker). Then connect a 1/4" cable to its stereo link out, with the other end of that cable connecting to the stereo link in of the second KC-300 (your right speaker in this case).

2. Connect your keyboard's L out to the L of channel 1 of your first KC-300 and connect your keyboard's R out to the R of channel 1 of your second KC-300.

The advantage of method 1 is that if the distance between your keyboards and one of your KC-300s is short, then you can use shorter cables to link out to that KC-300 and use only one long 1/4" cable to link between stereo out and stereo in of the KC-300s, but then the channels of the second KC300 (linked with stereo in) will be disabled automatically. If the distances between your keyboards and the 2 KC-300s are equal, method 2 allow direct hookups without the extra stereo link cable.

I hope you get the picture.

Thanks,

Paul Ip
from Texas