A recent NY Times article notes that our reaction to music is emotional and physiological. Fifty years after the fact they've acknowledged J. Gordon Holt's "goosebump factor." The only difference is that when the NY Times is referring to "music" there's no distinction between live or recorded, high or low fidelity.
The "Goosebump factor" for J. Gordon was mindlessly simple; if a piece of recorded music gave him goosebumps, it qualified as a good recording played back over a good system. For me a similar phenomenon is "The Ahh Factor." Instead of goosebumps, I just relax, exhale, and inwardly say "ahh..." when a system reaches a certain level of fidelity.
At audio shows my "Ahh Factor" is one of the ways I separate out the good systems from the great ones. If, after thirty seconds my body begins to relax and my shoulders come down from ear-height, I'm in the presence of a great audio system. It usually happens less than a dozen times per show, but when I switch from showroom uptightness to deep listening mode, the "ahh factor" has kicked in.
At live concerts I go through similar experience. Usually when I first take my seat at a live concert it's usually difficult to settle down and zero in on the music. But if the music is good, after a few minutes I can close my eyes and concentrate. Often after a couple more minutes I also get slightly sleepy and drift into a deeper level of attention similar to what I've experienced during meditation.
Even at home listening sessions it usually takes a few minutes for me to relax and get into the right mental state for serious listening. Sometimes I let myself go into a light doze at first, then do my listening. Other times I can go right from casual background listening to deep concentration without any intermediate steps. But regardless of whether it takes five seconds of fifty minutes, the final state is the same - relaxation combined with complete attention directed towards the music, which for me adds up to "The Ahh Factor."