I don't know if all brands of receivers are the same, but on the onkyo, I am curious. If I choose not to go with the audessey, and choose my own settings, is there a certain db level to start with
for the front.... center... surrounds...and do I keep the sub at 0db through all frequency range?
63hz
250hz
1000hz
4000hz
16000hz

Dreamer, if you mean where would you start if you were going to attempt to do a manual room equalization using the graphic equalizer, of course you start at 0 and adjust the response at that frequency either up or down, presumably by ear. However, if you're thinking that using the manual graphic equalizer is a relatively close substitute for what Audyssey does, that isn't the case. It's a relatively crude(compared to Audyssey)feature that affects only the few frequencies that you list. If one of those specific frequencies happens to be one of the areas where your room is causing a problem, then adjusting it will be helpful. Audyssey can make a hundred or more adjustments in some cases and it's suggested than when you have some time that you give its capabilities a full workout.

On the sub question, on your 606 there're a different set of frequencies for the sub adjustment, so you'd similarly manually adjust it(Audyssey doesn't equalize the sub channel on the 606) up or down from the 0 point if you choose the graphic equalizer.