Onkyo TX-NR 646 clipping?

[Pogre]

I wouldn't use this as the gold standard, and keep in mind it assumes 8 ohm speakers (I subtract 3 dB sensitivity for 4 ohm speakers), but it can give you a rough idea of the power required to hit desired spl at your seat. Just fill in the boxes and click calculate.

http://myhometheater.homestead.com/splcalculator.html