I've posted several previous times that my school district has gotten a new building with new equipment. Since our move this past fall I have become the unofficial "go to guy" with sound system questions. The latest has me stumped because it involves a piece of equipment that I have never seen before and that I have not yet been issued operating manuals for. Our middle school gymnasium has four EV speakers being powered by 2 amplifiers. The amplifiers are in turn receiving a conditioned signal from a QSC DSP-30 (or DPS-30... don't remember the letter order). The other day, two of the 4 speakers stopped working. When I looked at the rack, I noticed that one of the two amps were not showing a signal being received. I traced the wires from the amp to the back of the DSP-30 and noted that it was "channel 2". I thought... 1. It is either a wire issue or a channel issue. I switched the wire from channel 1 sending signal to the two working speakers with the wire from channel 2 sending signal to the two non-working speakers. The non-working speakers worked, the working ones stopped. I thought... 1. Ok... it is an issue with channel 2. 2. Somebody must have pushed some buttons on the front of the DSP-30 changing its settings. When I looked at the front I noticed a computer jack and two buttons (which I have no clue how to use either). At this stage... we're using what we have until the equipment installers return to inspect the equipment. My question... can anybody think of something I may have missed? Is there anybody familiar with this DSP-30? I know it is a digital signal processor and compressor, but that is about the extent of my knowledge. Any help would be greatly appreciated. Thanks! Tenor.