1st i level match w/ radioshack analog spl meter using test tones from anthem, & if adjustments are necessary i use the input level controls in the anthem. however, & perhaps it was just subjective, i at times find that different cd's still sound louder or softer between components, so when doing comparisions i generally have the spl meter out to make sure that the volume between 2 components for a particular song are as close as possible.
i have not tried doing any statistical analysis, nor have i ever tried to have dad or anyone else try to correctly identify a particular component when doing a blind test. i simply asked if they could tell a difference & if so, to try & describe what differences they heard, & then if they had a preference & why. from memory dad was almost perfect when i did not change the source, in other words when i played the same track from the same machine in succession. depending on the component, he was less than perfect in attempting to tell the difference between 2 different components. for example, telling the difference between a cary dvd 6 & a denon 5910 is possible, but difficult & imo no one would get this right all the time. the differences between a cary dvd6 & cary 303/300 were more pronounced & easier to determine. the 300 sounds more open in the treble, has more precise imaging & a deeper soundstage. for cd's one knows really well, the differences are even more pronounced. for example, in the first movement of dvorak's 9th, when the drums kick in, they are far more distinct, both in sound & soundstage placement, than w/ the dvd6 or the dvd7.
while i understand the relevance of doing statistical analysis, my comparisions are primarily for my own use in determining to buy a component. if it comes down to having to do a statistical analysis, i can already tell you that i'm not going to buy it, as if i can't make out the differences w/o doing a flowchart the differences if any are not worth my hard earned dollars.
i don't have a volt meter, & not sure i would know what to do with one.
my goal in the end is to determine whether a particular component provides a sonic improvement over what is currently in my system, & as important, is that sonic improvement worth the purchase price over what i currently own. for example, i have had a 5910 on demo for over a week. compared to my dvd6 for cd, it has slightly better definition in the treble (for example, cymbals sound more defined) & detail overall appears slightly better. the dvd6 has a slightly darker, more robust quality to it, the 5910 a slightly more detailed, more clinical sound. sacd & dvda quality was good but sounded on the sterile side to me, & in a completely unscientific comparison sacd from the 5910 was not a significant improvement over redbook from the dvd6, playing the same disc at the same time & switching back & forth between the 2, which i found very surprising, particularly when i had to struggle at times to determine the difference between the 2 players. the 5910 did have slightly better definition & detail on sacd than redbook from the dvd6, but it was not the significant improvement. as my primary reason for buying a 5910 now would be the high resolution formats (i currently lack a player for high resolution formats) & for it's video capability, this all but made up my mind.
i did not compare the video output of the 2 players, but i assume that the 5910 would bury my dvd6 which only has a 480p output. as my current sony only has s video inputs there was really no way for me to test in any meaningful way the video outputs of the 2 players. in the end, i'm not going to buy the 5910 as it was not a significant enough improvement over what i already have to justify the cost. if i was making the decision from scratch, & depending on price, & only comparing between these 2 components, i would buy the 5910 to use as a dvd player as it offers more options & improved video quality over the dvd6. however as i already own a dvd6, & the 5910 did not offer significantly improved sound quality over what i already have, i'm not going to buy it.