I have not been able to find a copy of DVE locally since it's release and I haven't bothered ordering it. I'm still using the original Video Essentials and the band-limited pink noise supplied on it. I believe the full range tones are useful only if you are calibrating through an equalizer, such as calibrating a .1 channel through a Berhinger Feedback Destroyer. I do not know the tone difference between DVE and the THX optimizer on certain discs. I always calibrate with an actual calibration disc and leave it at that. I read somewhere that the THX optimizer on each disc is different and useful only for the movie with which it is supplied, IE the Raiders optimizer will be different from the Empire Strikes Back optimizer, etc... HOWEVER I have never tried an optimizer so this may not be true. As for the SPDIF being louder, I do not know why but it seems to be the case that it will run quite a few dBs hotter than analog.