I envy your exposure to this level of live sound, morricab. I do understand what you and Ked are describing, and I tend to agree: this is how I experience live sound and good reproduction, more so with analog than with most of the digital I have heard. I often focus on the "completeness" of a note: attack, sustain, decay. When a cartridge/arm is properly set up, the note is more complete. In a recent direct comparison between a Berkeley Ref DAC and the dCS Rossini that I auditioned with Al M., the sense of flow, continuousness, seamlessness and completeness were precisely the differences I heard between the two DACs. And, like live music, the preferred DAC helped me to feel more relaxed. It sounded more right to me, more like live music. When the sound is not natural, something is amiss and that causes tension and stress. My mind and body can not succumb to the music around me. In that sense, I refer to even the most exuberant brass or string section or solos as "relaxed" with flow, continuousness, and seamlessness.
I wonder if the disagreement is between whether the music or the listener is "relaxed". I tend to describe the listening experience as "relaxed", that is the listener is relaxed because his mind/body is not struggling with artifacts that sound unnatural. He is able to let go and loose himself to the music. Perhaps some describe music or the sound of a system as "relaxed" if it is slow, soft, or lacks energy. So much of audio discussion seems to depend on semantics.