Speakers that disappear

Some do it better than others. ;-)  Planars have been mentioned, Joseph Audio.  ProAcs are well-known for "disappearing" and throwing a big, open, coherent sound stage.  That's one of many things I like about my old Response 2's.  I'm rarely, if ever, concious of them.  Nesteroviches disappear amazingly well for an old-fashioned "box" speaker, but they're getting hard to come by and the drivers aren't replaceable.

I had Focal Aria 906’s on the factory stands and could easily make mine disappear at the front of the room.  Soundstage was nice and wide, and you could not pinpoint the exact location of the speakers. Phantom center channel was right where it should be. In my room that ended up being with slight toe-out (not in).  What did you find with the 906 that you could not accomplish. As others have said a lot has to do with the room as well.  I have since moved on to Aria 926 with similar results (but the 926 require toe-in and a slight tilt forward). 

After you do all of the above, turn the lights off at night, poof…speakers disappear. I’m completely serious. After hours of placement experiments, some room treatment, center seat of sofa in just the right spot, well recorded track, lights off and my Klipsch disappear completely. The only thing you can see are a few LEDs and the beautiful glow of 845 output tubes. Spooky good! 

Same theme in the responses here, Room treatments, Set-up, and Synergy. 

Not sure of your budget but another idea would be the MBL 126 I have not heard it but it does get incredible reviews and seems to have the traits you are looking for.