Creating a Large Sound Stage

Or finish your undergraduate stereo degree and go to multichannel audio graduate school (like 360 reality,  atmos and so on....) soundstage sprawl and envelopment for days...

While most everything matters, the preamp usually provides the soundstage IMO.  We recently had a pair of Vandersteen Quatros up against a wall and we were getting 4D soundstage with the tube preamp used. No room treatments, used so it can be hard to say what will work in your room and system.

Happy Listening. 

Speaking of the 360 soundstage , marantz av 10 has 16 channels and now music is producing more music in atmos. The dirac does not care if the couch is in the way.you paid big bucks to have a sound engineer  come to your home and set it up but now it's built in. The audiophile avr are here now you can put any amps you want on it with 16 xlr 4 independent xlr for sub run on its own channel with dsp control to match them all in synergy. Read the reviews cuz it takes a triton like processor at 4x the price to beat it. Enjoy the new technoligy

After 40 years of professional experience it comes down to a couple of factors 

1 the equipment must preserve all spatial information by virtue of having good resolution 

The speakers must also have low coloration high resolution and good dispersion 

The room must not be too reverberant and the speakers need adequate space

We have found dual concentric designs like Kefand cabasse image extremely well

Dave and Troy

Lots of apt observations above.  One thing I always do when setting up speakers is listen to Her Majesty stereo from Abbey Road,  Paul's voice starts far right, moves to the center, and then moves left.  I listen for focus, starting and finishing width, clarity, and consistent volume at various locations.