Stephen S

There are a couple of ways to do this. I only did this with a single keyboard as an experiment to see what the SS approach would sound like. It requires 4 mixer channels per stereo keyboard, and a mixer that has a polarity reverse switch on each channel. Let's assume that you are using the first four channels of the mixer for one stereo keyboard, and 2 "Y" cables: Mixer input 1 - keyboard channel left Mixer input 2 - keyboard channel right Mixer input 3 - keyboard channel left Mixer input 4 - keyboard channel right Now, pan inputs 1 and 2 to the "left" mixer output. Pan inputs 3 & 4 to the "right" mixer output. Press the "polarity" switch on input 4. This will give you L+R on your mixer's left output, and L-R on your mixer's right output. There are other ways to skin this cat, too, but they get slightly more complex in terms of wiring.

Yes, I've done this. Used 2 powered speakers, one facing forward (L+R) and one pointed to the side (L-R). I don't have a SS to compare to, but i gather that the result is the same. Depending on your mixer, you can accomplish this with 4 input channels and a couple of Y cables.