Is it possible to really know what you're doing?

Interesting philosophical comments throughout.

I guess my real focus was related to the technical aspects of audio systems. Given how complex these mystery boxes are, does anyone really understand what they're buying absent being an engineering tech savvy individual and there are many of them here on  this forum giving great advice.

I agree that a reference / standard needs to be established.  Former dictionary such as Oxford English Dictionary (OED) defines a stereo(phonic) system as a system of sound recording or reproduction using two or more separate channels to produce a more realistic effect by capturing the spatial dimensions of a performance.  So, imho, two keys elements defines a reference stereo system:

1. Realistic effect; and

2. Spatial dimensions.

In my pursuit of a reference audio system, I aim to achieve a setup that faithfully reproduces the tonal character (timbre) of instruments and voices with a high degree of accuracy.  This includes precise imaging—where each sound source is rendered with a clear, stable, and locational presence within the soundstage.  So, I were to lay out a specific metric for the reference system including:

1. Timbre accuracy;

2. Imaging; and

3. SS width, depth and height.

This metric may not be measurable instrumentally, but it can certainly be perceived in your listening space with a good pair of ears and a discerning mind. I believe you could always expand this metric to include many more elements you consider paramount. But bear with me for being simple-minded—and tell me, are you there yet?

It’s possible, but not many do. Have fun tweaking my friend and may the force be with you.

@emergingsoul said: "...does anyone really understand what they’re buying absent being an engineering tech savvy individual....

I think if it were based purely on engineering, one could do this in what I referred to above as a "holistic" approach, using specs and compatibility, room analysis and the like. My experience has been that every piece of equipment has some characteristic (coloration?)* that requires a more nuanced approach to matching pieces to achieve a result that works as a system. And that doesn’t even address room acoustics and placement (which again, can be done remotely by analysis but ultimately, to me, is also fine tuning by ear). 

I addressed your original question by observing that I don’t have an holistic approach to system building, since I need to hear the various components in combination in a given room, taking account of set up and placement. I readily admit I’m a subjectivist and don’t rely on specs or measurements alone, though I respect the engineering aspects and some of the basic issues like matching speaker and appropriate amp, impedance, gain, etc. 

*One thing I've observed on my journey in audio is that you often don't know there is a coloration until it is absent. That is often a revelation. 

@whart 

Thoughtful comments.

I dare say you know what you're doing.  Awesome Horn speakers and a turntable and everything else speaks highly of the wisdom you possess.

What a lovely space you have.