DEANE; yesterday for the first time I used just one s1 pro with just one cord coming from left out on my keyboard to channel one of the bose. I usually just run 2 in stereo but I have a last second job call in so I tried mono for the first time. It was the best mono sound I have ever gotten with any keyboard. I will use 2 for stereo whenever I can but I was shocked how great it sounded in mono. I love mine and hope you are enjoying yours as well.
MEL