The mastering engineer can mix any sound/instrument recorded in only three ways all the volume in the right speaker, all the volume in the left speaker then anywhere in between. Unless he resorts to staggering phase and other tricks the sound is going to come from the right speaker, the left speaker and anywhere in between. If an instrument images outside of the stereo pair it might sound cool but there is an acoustical problem with the room. This is the only way that can happen under normal circumstances. Forget about how the recording was made although it is nice to get the acoustic ques of the venue into the recording it is because of their low levels that reflections can compete with them and make it seem as if you are in that venue but the high level of the instruments themselves should always come at or between the speakers. There is no other way to mix them without tricks. This is not IMHO Magister is a matter of fact.You describe here the recording process forgetting that it is not a description of the acoustic experience you just did...
I listen to the "Gabrielli" album from Empire brass ensemble for example...
The sound comes from the external right and external left OUT of the speakers simultaneously with a very good deep front/back imaging...
I listen to many album and many present a deeper front/back imaging sometimes filling the room and between me and the speaker.... I am among the players and not sometimes in front of them at distance...
In general more than half of my albums make me forget the location of my speakers because the piano for exemple may sound in my room with a chord distibution from front near me,to back behind the speakers....i am near the piano able to touch the instrument....
Example: Moravec Chopin Nocturnes or Feltsman Bach Well tempered Klavier...Try these 2 and if the piano dont fill the room few inches from you , your system is boring and not acoustically very impressive... Sorry...
Buy these 2 albums very well recorded and if the sound dont fill your room your acoustic control is bad ....Simple....
Must I called it a sound between the speakers because you think that it is the norm? The sound is AROUND or coming way out of the space between the speakers and sometimes the 2 at the same times it is relative to the mic location in the initial event... ....
You forget that acoustic is NEVER perfectly seized by the recording process but the recreation of the 3-d atmosphere of the initial recording is most of the times possible IF we control the room....It is not magic it is science....
BEFORE my acoustic controls were in place the sound was always between the speakers, never outside them by the right or left and never near me, and never with a great front/back distribution in space....
After with the SAME components the situation were completely different...
Then acoustic controls explain it most of the phenomena ( with vibrations control for some degree)