I’ve listened to some pretty humble speakers that successfully disappeared, so I really don’t think this is significantly a property of the speaker.
A good room with speakers and seating placed well in the room seems to me all that is required as long as the speakers don’t have extreme faults.
I certainly see something to that. it doesn’t seem to take much for a pair of stereo speakers to produce a stereo presentation, and naturally that’s going to mean a lot happening in between the speakers.
But then, and I think it’s clear many of us have had this experience, there just seems to be speakers that take it to a whole new level.
Even when you were used to regular stereo imaging, some speakers seem to “ disappear” just that much more so you kind of go “Whoah.” That sense that you can look right at the speaker and not get any sense whatsoever that they are creating the sound is pretty neat.
As I mentioned before in my experience a number of audio physics speakers seem to do that really well, as did my MBL omnis, some Waveform speakers that I had (egg shaped mid range tweeter enclosure).
My current floorstander speakers do that very well too.
I also had the Thiel flagship 3.7 speakers and the slightly smaller 2.7 version of those speakers in my home at the same time for quite a while, going back-and-forth between them. Although the 3.7s were the bigger wider speaker, they actually seemed to
“ disappear” a bit better, in the sense that even hard panned instruments seem to float more free of the speaker. I’m not sure why, if perhaps there is some little resonance or something calling attention to the smaller 2.7.
I know the 3.7 was a bit more of an ambitious design, with the front baffle holding the drivers being made of solid aluminum, and a solid aluminum cap. Versus the cheaper MDF front baffle of the 2.7. so perhaps there’s a little little bit more resonance going on with the 2.7? I don’t know.