I agree with Mdrew. +10db is very hot and will overwhelm the speakers (and your neighbours) . I run my 3subs combined flat with the speakers at 75db and the sound is well balanced. Occasionally I nudge up the subwoofer level a notch or two at the processor depending on how the soundtrack was transfered. What speakers are you using and what are their FR specs? Better results can sometimes be obtained by setting the crossover 1/2 octave higher than that bottom FR spec for speakers that extend to 60hz or less. Also remember to add 3-5ft to the subwoofer delay to account for the DSP in the 600 and its vented design.
