Thanks for the suggestions guys but I've solved the problem. It was caused by a null at the listening position at 1Kh which is the reference tone. I recently added some diy room treatments that caused the null which wasn't there before.
I took a reading at 1Kh and another at 4Kh and then used the difference between the two and it worked out fine with a little speaker repositioning. But I'm still puzzled by the mains putting out that much output at 63Hz when the crossover is at 120Hz when there is supposed to be at least a 12db drop between crossover settings.
Craig: I set my crossover at 120 because that is where I get the most even response from 20hz-200Hz and I have my sub positioned between the mains. Localization has not been a problem. But I think the bigger question is:
If the sub is positioned in such a way that there is no danger of localization (as mine is), why not have a higher crossover point.
I mean, we have subs such as the HSU,SVS,etc. that are highly capable of producing high quality clean bass above the widely accepted 80Hz point. Do we all use 80Hz just because THX says so.? Did we all buy expensive subs just to supplement our "full range" speakers with the bottom octave?
I think a higher crossover for the sub allows greater flexibility in speaker placement and takes more of the burden off the amp and main speakers which could result in less distortion and compression.
If a sub is crappy enough to sound poor at any crossover point, then yes let the mains handle as much of the bass as they can.
I have yet to hear a good reason (other than localization or if the mains produce higher quality bass) for not using a higher crossover point than 80.
Here is a terrific article that touches on this subject.
