I think you will find that the auto calibration set up for just about everyone are on the sensitive side. I do not see hooking up another microphone helping in anyway as the calibration tool was made to work with that microphone. So hooking up a more sensitive microphone may actually make things worse if you are picking up background noise now. I will be honest, I am not a big fan of Onkyo's lower line up of receivers and there specification are lacking. But at the same time what can you buy for that same amount of money, a Sony? Sony receivers IMHO do not sound as good as the Onkyo's and I doubt there auto calibration is as good as the audyssey set up. You could go with a Denon but that would most likely set you back more money but could very well be worth the investment. You also might want to consider an 805 over the 606 if you can still pick one up online for around $700? The 805 may not have the better scaler but if you are not concerned about upscaling, you can always set the 805 to pass through and let your HDTV do the scaling. The 805 audio wise would defiantly stomp the 606 guts out all day long and you might want to consider it as 805 may not be around much longer.
