The stereo image is an audible illusion. Our ears/brains are being tricked into hearing sounds distributed throughout a spatial field. High Fidelity does an amazing job of making the room feel like it is full of musicians. And this can all be done with just two speakers. Changing cables or changing gear can disrupt the timing cues and the timbre of the music and since our senses are comparative we tend to decide we like one version over the other. Hence we will sometimes flip back and forth between two versions in our stereos unable to decide which we like better. That is not the basis for calling something, “snake oil“. It‘s much easier when we find a clear difference that we definitely like but don‘t be surprised if others disagree.
A/B blind testing works best with a group or panel of jurors because differences of opinions always arise in all but the most blatant of changes. In the end its your system and you can set it up like you want. I‘ll be the first to criticize it if I don‘t like it. But it is just an opinion. Maybe someone will measure their system‘s response in their room and argue it sounds great because it measures great. Sheesh!
To me, a great sounding system has clarity. That is high contrast from zero sound at rest to clear, powerful crescendos at the peaks. Bass is full, robust and clear. I can hear the fingers plucking the bass guitar strings. I can hear the timber of the drum heads. Voices are captivating with a reach out and touch them realism. Horns and brass sound like real horns and brass. Cymbals are crisp and delicate with a feel like they are right there. A piano sounds like a piano in the room and I can almost smell the wood of a stringed instrument. Rhythm and Pace that makes the music flow out of the speakers and captivates. No harshness, no fatigue and no sibilance- no cotton ear after listening a while at moderate or high volume.
A bad room can muddy the bass and mid bass. It can also accentuate sibilance. A/B comparisons will be clouded/confused if room interactions are interfering with the music. Some people will be more sensitive to that than others.