In my system, the main left and rights and the surrounds are all on "+6" on my Onkyo TX-SR600 receiver's calibration setup; the center channel is at "+8" (to compensate for low dialogue over effects, etc.) and the 10" powered Polk sub is at "+6" as well. Originally, I had the sub at like "+7" or maybe even "+8" at some point on the calibration levels, but that was causing certain extreme DVD soundtracks to make the sub create a very loud "popping" or "snapping" noise, for instance during the senator's ship exploding in the beginning of "Attack of the Clones" (running in Dolby Digital EX) or when the chariots hit the wall in "Gladiator" (running in DTS ES)....my solution was to ease the volume back on the actual volume knob of the sub itself AND reduce the calibration level of the sub down to "+6"; this seemed to stop the sub from snapping during extreme scenes in DVDs. Now, though, I feel as though some DVDs just dont have the impact Im looking for in LFE...and stereo music has no punch with the sub at "+6" on calibration. I have been told so many theories about a subwoofer and where it should be set in a surround system. What is the correct answer? Some have told me that a subwoofer should be at least TWO DECIBELS higher than what the rest of the system is set at...which caused my bass to be way too overwhelming on some DVDs. Then I have heard that 10 dB more than the mains is what subs should be set at...as a rule, should a sub be set higher than the other speakers in a 5.1 array?