OP, To me it’s when the tone and body of the instruments and voices sound lifelike. I attend live music events regularly so I have some basis for comparison. Good topic by the way
You know you have audiophile system when...
The definition of an audiophile systems is truly unknown, but recently after dabbling with tube rolling, power cables, and interconnects my system achieved a level where its clarity was no longer what grabbed my attention. Instead, I was distinctly hearing the bloom and decay of every note in the music. It’s just a different level that I believe has me listening to music differently. It translates into greater dynamics and voices and instruments having more distinct vibrato characteristics.