I received my 990 today, made all the proper connections, then ran the auto setup. Well, it would not recognize the sub. I have 2 NHT 10" subs powered by an external amp. When I calibrate using the test tones, I can't turn down the channel level low enough to match the other channels. The amp does not have a volume control. Any suggestions? Or should I even be using the test tones for calibration of the sub? Thanks, Kevin Brees