Gilliland said:
The only way to do that is via a blind test.
See, I don't know about that. I test things in my studio all the time; I don't do it blindly; I use analysis tools and repeatable programs. There was some discussion in the thread on Klaus Heyne's board about using MIDI pianos or organs, and that is definitely one approach. I use even simpler methods; white noise or the canned programs on my digital keyboard.
With that methodology, I can't necessary tell what is better, but I can tell what is different. If the files don't come pretty darn close to nulling, there is a difference.
From there, it should be possible to study what caused that difference. If it can't be explained by ohms, henries, and farads, then we need a new science, but it's still a science, because it is observable and repeatable. After all, how do the cable companies know what to design? Are they just alchemists? (don't answer that

)
That still doesn't tell me which one sounds better. But once I know that is it no trick, no placebo effect, it's easy enough to proceed anecdotally.
Even so, I don't trust my ears, because they lie. I know this is heresy around these parts, but it's true. How many times have you woken up to the mix the morning after and wondered what the hell you were thinking--or hearing--or drinking

? If only it were possible to mix to a graph, because the graph showed the exact same thing last night as it does this morning.
But we can't, music is subjective, so we must use a subjective tool: ears. But when ears and objective measurement agree, that is a powerful conclusion.