It's funny, on one side we have Al M. and Bonzo saying that only direct, head to head comparisons are the way to get at which piece of gear sounds better and then we have you now saying that it is mostly useless and sometimes misleading. IMO, DACs are one of the most comparable pieces or gear in a system because there are usually minimal interface issues. Speakers and amps are much tougher to compare because of impedance and sensitivity matching issues. As long as a DAC is fed into a preamp then impedance is not an issue and the signal never transitions from electrical to mechanical or vice versa.
Yes, I openly disagree with them on this aspect. Electrical characteristics are not enough to explain or debate components matching - 99% of modern electronics are good matches. The impedance rules - there are a few versions, can you tell me what is yours? - exceptionaly explain a few cases of mismatch and admit as many exceptions.
It is not practical or really necessary to build up an optimal system around all pieces of gear on test in order to determine the character of a piece of gear. They all have unique signatures. This can be modified or ameliorated by other components in a system but usually not eliminated.
It is not practical, but IMHO it is the only fair way of carrying a proper review. Surely YMMV, as people say.
Sorry to say, if you made it yourself it is not significant for test unless openly accessible to everyone - unless you were able to carry with high quality a challenging recording and have excellent recording practice and credentials. I enjoy Perter McGraph recordings, but every time some one comes with an amateur DAT recording I go for a coffee.Using high quality recordings that one knows well (even better if you made them yourself as I have done in a few cases) is always important but this can also lead you into a blind alley so I like to also mix in ones I know pretty well but that I don't use regularly for reviewing.
Knowing what are our reference recordings helps a lot in these subjects, it would be great if we add them and the why's in our "About" pages, that are easily accessible any time. But I have found people love talking with great detail about equipment in reviews and much less about the music reproduction - I recognize it is a much more demanding aspect concerning writing skills when some one wants to be detailed, most of the time I feel difficulty in expressing it.
So, what you are telling me about Vivaldi, SOUNDS like it has issues that have to be counterbalanced or it doesn't reach such a high level of performance...if that is not what you are saying then what do you mean by optimization of a system around Vivaldi. It sounds to me like the Metronome is far better choice for most people who will generally drop the new piece into an existing system. Are you telling met that the Metronome has more coloration overall but is somehow "more sympathetic" in its colorations or are you saying the Vivaldi reveals all the weaknesses in ones system and requires a rethink? Or are you telling me both those things? Try to be less cryptic.
I am not obssessed with DCS per se. They were; however, one of the focus DACs of the OP, so...
No, I am just reporting what happens in my (and a few other) systems. It is a question of subjective matching, but yes the Vivaldi often needs a rethink of some parts in the system. When you have too many good things you want to have them all