Why don't more recordings have soundstage outside of speakers

@mijostyn Oh, man -- I’m all over that mic sh*t. I dream in waterfall graphs, dude. Love that stuff!

@snr Glad you could bring your expertise in for all us lunkheads. Thank you for your wise thoughts.

"The room" is really just another part of the system. For a long time we thought the way to treat the room is like the way we were treating components. So we put huge tube traps and panels everywhere. Now we have a much more sophisticated view of vibration control. Lots of things now we want to suspend on springs so they can move independent of the room. Because we can hear this reduces ringing and greatly improves detail resolution. A good example, I put my crossover back inside the speaker but on Townshend Pods, with a huge instant improvement. A lot of the improvement comes directly from the control (precision damping) of resonant behavior. This same general principle is at work in their Podiums, speaker cables, and interconnects. That explains why after upgrading to a lot of this I noticed a huge reduction in bass bloat or tubbiness that I was until this point sure was a room problem.

Clearly then it was not. Imagine if I had gone to the trouble of "fixing" it the conventional way. I would now be looking at how to get rid of the great big tube traps sucking bass out of my room. Instead I use a mix of a small amount of cleverly placed panels combined with more next-generation treatments, Synergistic HFT. These are I guess room treatments, they definitely improve clarity, imaging, etc, but in a quite different way than conventional panels. Way more effective than old school panels. And I know, because I tried the panels!

So the room is no different than any other component, equally important, and like any other component a huge part of it is vibration control. With the room even more so. Also like all components it benefits from a more sophisticated view of vibration control. 

As others have said there is a sound engineering 'trick' in which you pan an instrument or sound hard to one side and then mix in the same track panned hard to the other side but 180˚ out of phase. At the mixing desk it pops the track right outside of the speakers and leaves lots of space in the centre of the mix... which is very handy in a lot of cases. The effect only really works on a stereo loudspeakers, it doesn't work on headphones and in mono the instrument or sound will be greatly attenuated as the out of phase signal is summed with the original. In most cases an engineer doesn't know how a track will be listened to (with the exception of vinyl) so effects like these are used pretty sparingly.
Many systems are able to render a soundstage wider than the speakers even when there are no 'tricks' like this in play... I enjoy a number of recordings made with a single stereo pair of microphones that have a huge soundstage. In my experience it's usually down to the recording and the loudspeakers. An average room is capable of a wide soundstage as long as there is enough distance between the loudspeaker and the side walls to avoid flutter echos. You can put absorbers at the first reflection points (imagine the wall is a mirror and you're looking at the reflection of your loudspeaker from your listening position) to tame the worst of these.

An average room is capable of a wide soundstage as long as there is enough distance between the loudspeaker and the side walls to avoid flutter echos. You can put absorbers at the first reflection points (imagine the wall is a mirror and you’re looking at the reflection of your loudspeaker from your listening position) to tame the worst of these

There is no average room because even if some rooms have the same dimension and the same geometry, they dont avec the same materials acoustical content and the same topology...-average room- exist only for acoustic panels sellers...And average speakers are like average room, a non existent species... Each type and format of speakers will ask for his own tuning relation with the room...

And this rule : "you can put absorber at the first reflections points" is only that , a general rule which dont apply half the time if we look for optimal results..

Why ?

Because controlling the reverberation time, and the waves timing flow for each ear specifically ask sometimes for the use of reflective surface not absorbing one at these points...

It is an experimental fact in acoustic that some reflection ratio between front and back waves and lateral one create a better detph imaging....Then a so called " average room" with an optimal speakers placement is only a first step in acoustic control.... There remain a long way to go...

@mahgister I meant averagely good acoustically which is not measurable but I think most would know what I meant. if you want to make everything sound like mystery and magic then go ahead, there are some basic acoustic principles that are worth trying before you turn to guesswork. I'm not even sure what 'an experimental fact in acoustic' actually means.