Center and Sub Calibration question

We obtained a calibrated analog sound meter and used the Avia DVD to set up our 5.1 speaker system. We set all speakers to be 75 db at the listening position, except the sub. Try as we might we could only get about 55 db from the sub. Some folks on this board say that the sub should even be 5 or 6 db higher than the others. That is well out of the question for us. Does this mean that our sub is underpowered, too small, whatever? This all sounds like too much sub for us anyway. Any ideas? Thanks.

Also, when watching DVDs the center channel seems too meek. Does anyone else boost the center cahnnell above recomended levels?

Doc@savemypc.com

First off, do you have the gain turned up all the way on the subwoofer? That kind of discrepancy typically has more to do with an incorrect setting rather than a defect in the unit itself. If the level indeed is too low, then you should get a Y-splitter and plug the subwoofer output into both the L and R channel inputs on the subwoofer. Doing this will boost the levels by about 6 db. Are you using a SPL meter to obtain your readings?

I would double check and make sure that you're outputing a digital signal from your test disc. Do the speaker ID test and see if the surrounds are blended together or if they are separate. If they are blended together, then you're probably running a two-channel analog signal in Pro Logic mode rather than discrete full range 5.1.

I would also make sure that the bass settings are done correctly. First, make sure that the bass/LFE output is going through the subwoofer and not the mains. Second, check the DD and DTS LFE levels. Third, check the output level for the subwoofer and raise it to the highest level if you need to.

Also, if your receiver's doing the bass management, either bypass the crossover on the subwoofer, or if a bypass is unavailable, turn the crossover frequency all the way to the highest setting.

If the center channel is weak, then you should simply match the level using a SPL meter. If the levels are matched, then any weaknesses that you hear have nothing to do with the center speaker, but with how the DVD soundtrack was mixed.

change your spl meter from A weighting to C weighting. A Weighting only hears frequencies from 500-hz and up. C-Weighting does the whole spectrum.

-Joey