Sound Stage and Imaging

My Ohm Walsh 2000s do what you want, as long as you don’t overdamp your room. $3800/pair new, but any larger Ohm Walsh speakers will produce similar results, and used, are often within your budget. Stick to models such as the 4 or 5, XO designation is a plus. Also 3000, 4000 or 5000, but they might be budget busters. The original, large F models are out there, and even refurbished pairs could be within your budget, but need powerful amps to sing. The future of the company is in the air since the death of founder John Strohbeen in October, but there are people out there besides Ohm that will repair these speakers if needed. I doubt you will do better within your budget based on your priorities.

Have never heard Ohm.

Vandersteen 1 and 1b locally, worth looking it?

Lower end Magneplanar or Best Buy Martin Logan?

Also of importance to mention: low bass is covered (Velodyne DD15 small room, Dayton 18" sealed driven by ED LT1300 in large room). So NOT concerned in this area.

With soundstage and imaging in mind, what helps with regard to the room:

a) hard vs soft BEHIND the speakers

b) hard vs soft OPPOSITE the speakers

c) hard vs soft SIDE of speakers

d) close or far wall   behind

e) close or far wall - sides

f) close or far wall - back 

Where 'hard" is reflective, non absorbent. 

Where for now to start NOT dipole, etc. speakers. 

Generic or General statement (each speaker is different, but some general rules apply). 

ADS "or pair of ADS L2020s, (which will fill your huge room) and / or ADS L1530s or L1230s. ": can't even find a PHOTO online of ADS L2020. The mid size LDS (L880 etc) look nice (I do like dome midrange, have a pair of Infinity Quantum 2 in parts in the basement, never heard them (no time to go over them, redo xovers). 

Can someone linke to ADS L2020?