This is something i have not noticed before with my B-Max into my 1602. When i have the amp set in paralell mode, one GS112 plugged into each speaker output, i notice that when i have just one channel gain turned up the speaker sounds normal, but when i turn up the second channel gain to match the first, i have net loss of volume and especially bass response in both. Turn either channel down and the remaining channel returns to normal. I also tried this in stereo mode using a splitter out of the BMax. Same result. Is my PLX going bad or is this normal??