Strange Results

[thxgoon]

First of all let me say thanks to John for the new REW. It is awesome with the spectrum analyzer and all of the new features! It runs flawlessly on the mac now. Wohoo!

So I was playing around with it today and I got some disturbing results. I am using the same soundcard calibration file and spl file as before but the FR are way different from when I first measured this system. Here is a graph from about 9 months ago after I completed my subs.



This is what I measured today



Other than the difference in volume, what could have happened to make this change? Both measurements are with the BFD filters deactivated. Today I tried completely removing the bfd from the loop but I ended up with the same results. It seems so strange that the low end response is suddenly gone. Is there something in the new REW that I need to change to account for this? Thanks!

[JohnM]

The difference is the soundcard calibration, in your earlier measurement you have a soundcard calibration result that rolls off very early, it's already descending rapidly at 100Hz. It looks more like a meter calibration file. In your latest measurement the soundcard cal is flat across the range displayed.

[thxgoon]

Oh ya, I forgot I had used a different computer on that first graph. Strange.. I'll try re-calibrating this one and try it against the old version too.