Well, guess what? Seems to be working now.
I checked the driver revision for the ALC883 chipset and mine was two revs old. So, I downloaded the most current rev, uninstalled the old ones and installed the newest.
Fired up REQW, cleared all settings and started from scratch (which I had previously done NUMEROUS times). I didn't change any other settings except selecting the sound card and appropriate inputs from the pull-down lists in the soundcard cal screen.
Went though the soundcard cal ensuring the input signal was from my loopback connection. Went through the SPL cal, again ensuring that the input was from the RS meter and that went fine.
So, ran a sweep and got about what I was expecting the first time through.
Don't know for sure if it was the driver itself, or the uninstall/reinstall process that reset something.
Thanks for your concern and suggestions. As the old adage goes "if it ain't broke don't fix it" and it seems it ain't broke any more.
