I currently have a hifonics zx6400 4-channel amp. The output is suppose to be 340 watts RMS x2 @ 4 ohms bridged. I am currently only bridging the first two channels and hooking it up to a sub and not using the 3rd or 4th channel at all because I haven't ordered the component speakers I was going to hook up yet. Is the output of the amp still going to be 4 ohms for those two channels if I don't have anything wired up to the other channels? I tried searching online for an answer but it doesn't seem to be a usual situation so I couldn't find any info on it. Thanks for any help you guys can give.