What does listening to a speaker really tell us?

Part of the voodoo here is that human hearing isn't linear. When midrange and bass tones are at equal sound pressure levels, the bass ones will sound subdued 'cause the ear is more sensitive to the midrange frequencies. The reason fidelity takes many forms stems from the basic question Pawlowski asks, fidelity to what?

Fidelity takes many forms. As you have guessed accuracy is one of the dead end streets in Stereo Town. It's on offer anywhere audio is sold.

Once you get past the idea of replica, reproduction and analog, jump ahead to speakers that best convey the emotional intent of the performance. How to know what the intent was? The better the speakers convey it, the more you'll know it.

Mark me as a person who having once fallen for "look at the perfect sine wave this unit produces" eventually graduated to a more mature understanding of the audio ARTS in all their varied subjective splendor. The good news is that anyone, who got suckered on accuracy as an equilvalent of audio nirvana AND is willing to admit to it, merits an opportunity to explore the wonderful world of perception called musicality. Great topic!

Pawlowski I like your formula idea. Let's say Performance plus Recording plus Playback equals Experience. Which props up which? Maybe they're all interdependent. A purist might say let's get the Playback to be totally invisible, remove it from the equation, get it to approach zero. That's a comfortable concept, right? However a pragmatist might give Playback a positive value to enhance the likely outcome. A realist might rationalize the value of whatever he can afford. A hedonist might escape the equation and redefine the Experience. Obviously there's more than one way to dig in. So how's this for a new equation for how do we know? Experiment plus Observation equals Awareness.

...then a boombox can be equal to A. Porter's system...

Audiotruth Number 132466: The only system that actually matters is the one in the room you currently occupy.

PBB, I didn't forget you. One of the basics of sound reproduction and perception is that the ear's sensitivity to frequencies changes with the sound pressure level. Ever notice that there's a just-right playback volume? For example, below that level there's not enough bass, above it there's too much. That's your ear at work. In the context of this thread this means that the elusive wild goose of transparency can only occur at one volume setting for each recording. At all others the perfect system will sound out of balance, and so by definition, non-transparent.