I have the AVIA calibration disc, but got the new Sound & Vision Home Theater Tune-Up by Ovation in case it had some new features. Besides the DD 5.1 test it also has a DTS test track. Guy Kuo says the new disc is aimed at newbies; as such, it doesn't recommend any hard reference level, just something over 70dB on the SPL meter. I chose 75dB because that has been my AVIA level. After calibrating to my 75dB reference with S&V Tune-Up disc, I found that left me at -26 on my Yamaha amp volume. (00 is max and -99 is lowest). I then went to the audio tones in the original $40 AVIA Guide to Home Theater. It was the same level. Decibels is decibels. Now here's the twist. The new Ovation disc has a DTS audio test that Avia does not. I found the DTS signal significantly LOUDER than DD. In practice, I had to lower the amp volume to -30 to reach the 75dB level I hit with DD at -26. So it appears that a DVD movie disc that's set up to DTS may be louder -- initially -- than the DD soundtrack. Maybe this is why many say DTS is "clearer" or "more dynamic" or whatever. This just my finding with the test disc -- it could be that DVD movie sound engineers compensate for DD and DTS so the playback sound levels are about the same. The serious tweaker will watch a SPL meter at the listening position; most folks will just adjust the volume to whatever they can be comfortable with... All these disputes about which format is "better" don't matter because it's whatever sounds best to you.