Just my comments on your findings on this matter :
As you might know, apart from standing waves whatever philosophies, I try to form more "theories" from different angles, in order to be in the end able to explain Audio.
Explain Audio ? yes, because there are, in fact, so many things that are unexplained so far, or can't be justified by scientific means.
Let's say I'm on a kind of right track already, because XXHighEnd sort of
does what I expected in advance, while at the same time officially it should sound like ... you know.
Gerner, at this time of the evolution I can be very wrong, but I would (like to) dedicate your finding on this matter to the
ability of original sounds to re-emerge in the room during playback. This, versus the matter of things not being recorded.
That I dedicate "this" to your finding, it just a hunch (but let's say for now I'm good at hunching).
Please note for those who don't know me, or generally think my writings are too long that my life consists of writing maybe 10 or 20 of these pages per day, which just sets my mind, in the end having learned something. So yes, most often this is brainstorming with myself, which is just for a good cause ... for ME. Might you benefit form it too ... 
So, opposed to the standing waves principle about which I wrote rather often by now (bd-design), the phenomenon of waves recreating in mid air by means of proper playback I've written about only once maybe (bd-design again).
Gerner, I am not all that much saying that what you experienced is because of that, but merely because of it happening, you receive the
opportunity where otherwise it wouldn't be possible.
I think that "music data" which was not able to get it to the recording, can just emerge again in the air where the elements of the music data are being played back. Example : supposed each individual string of a guitar were recorded by means of individual microphones, the harmonics of them playing together, would not be recorded, right ? Now think of it ... with an electrical guitar, this just would be so (individual microphones -> the element with 6 microphones).
Of course, when we listen to a live concert, we do not perceive the individual strings, because from the loudspeaker all is already merged, and what we hear would be the reality of the harmonics of the together played strings (chords).
This doesn't sound (no pun) so bad, does it ?
Right.
Now especially for you Gerner, if you're not awake, you will be !
We now jump over to our Ben Harper and his Cruel World ...
I think I now just start to be able to explain what went wrong with this very good example of the instruments falling apart in the crazy dynamics Engine#3 Double version ...
And I think you can guess what's coming next ...
For the others : This track (Welcome to the Cruel World from the equally named album) is (like the other tracks) about playing the electrical guitar with chords. Engine#3/Double shows these cords in a very very interesting way as all the individual strings being very well audible, and you could say that where we audio freaks are always seeking for separation of instruments, voices and the like, Engine#3/Double shows the individual parts of the instruments. Veeeery interesting, crazily impossible, but just happening. Also, this is the version with the crazy dynamics, the SPL meter not showing the perceived SPL level, but your ears do ...
Now what I say is : with this #3 version the individual parts do not play together, and where harmonics of the treamplay don't get a chance, most probably the antiphase elements of a drum smash etc. don't get a chance either (so all is pronounced unnaturally).
What XXHighEnd does (stribes for anyway) is getting the phase of all right. This is about this -theoretically anyway- one very small point in space where all has to be right. When this one small point is expressed as, say, one cubic cm (which is even rather much), now you do the math (with speed of sound and length of waves for individual frequencies) how accurate things have to be.
Now, since #3/Double should be more accurate than #3/Normal (or #1 and #2 and #2/Double for that matter), things go over the hill. BUT :
And this is for Gerner again ... this was with the, say, MKI version of the Orphean/BD15.
We (Bert and me) already found that what can be done with software (no DSP !) can also be done with loudspeaker filters. Well, to a large extend anyway. Trust me, the differences with a filter can be day and night (and within 0.5 seconds audible -> I mean this), but only when the source is right !!!
Now things kind of backfire ...
Where #3/Double was over the hill wil the MKI, I don't think it is with the MKII. And haha, I didn't even try !!
But the fun is, I don't need to, and I think I can reason why;
Where the MKII became better in all aspects, it got rid of a, say, level of freshness at the same time. Freshness which is (and was) of a crazy high level anyway, without a flair of disturbance, but Bert as well as me do want more of it with the MKII (and Bert, I know this was only here and there in between the lines, but I think I may speak for you on this matter). I sense, I feel, I KNOW that today #3/Double will perform as intended. It now fully coorporates with the MKII filtering. It went over the hill because the MKI couldn't really cope.
And again, I am just reasoning something out, but the fun is, that I always do this in advance. So, obviously I could go and listen first before this writing, but for me it is much better if I turn out to be right; It does not give me the opportunity to talk into directions. Otoh, if it turns out I am wrong, I have to explcitly find the reaons of why.All together, on the topic, XXHighEnd is about getting the things right, and I state that the most of this happens in mid air, and not in the speaker, in the amp or wherever we might think we can enhance the sound. BUT, all these elements can destroy !!
Isn't that the same ? well, yes, I think it is. But mind you, when the angle is "it can destroy" your tweaks will be different !
We all know about the filtering cables, and that cables might bring you less sharp highs. BS !!
BS if you understand what my objectives are : putting through the sound as unaltered as possible. THAT brings you the good sound. Uhhm ... the NATURAL sound.
If you (Gerner) are now able to hear the antiphase of a single voice in the midst of all, this is
a. because you are very adaptive to it
b. because the very accurate phase mappings.
With b. I don't mean that this individual voice is accurately reproduced, but that ALL is accurately reproduced, because of why the individual voice now can be heard properly.
For now I want to end this post with a remark of similar order, though the subject is very different;
Instruments can be played back rather separated in many systems. If all is rather okay, this just happens satisfactory. Also : I never noticed that XX would do this better in the higher regions of the frequency spectrum (for the lower regions yes, because the standing waves would mask everything otherwise). But :
What *is* very much noticable, is this :
Suppose you are not into metal or hardrock and the like; in that case you wouldn't like the screeming guitars, right ?
Well, just try them again ... What happens today with XX, is that the normally screeming mask or flair all over the total sound, has become so completely separated, that there is no such thing as a mask or flair of screeming. There is just this one area in space where the guitar plays its rough notes. Actually it is rather interesting, because the guitar can have it. It was made for it. "That" music was made for it. All fits. It's not screeming all over the sound. It's screeming a little bit by itself. Let it go ... let it flow ... Just listen to what this headbanging plectrum thrower makes of it ...
