OK, I plugged my electronic piano into a mixer, and connected my mixer output with a coax/SPDF cable into the rear of the DSP3100. I can't hear anything.

Since I am removing the DSP's from my home theater setup, should I disconnect the COMMS cables etc from the rear?

G68SL, G98DH, DSP5500, DSP5500HC, DSP3100, JL Audio F112 Sub, DirecTV, Sonos, 4 Revivers (Highend-Source)