Speakers that disappear

+1 @rick_n 

Every flat surface in the room becomes a transducer and effects the original sound wave. 

Not known for the diminutive size or WAF but once you hear a proper open baffle set up correctly its hard to forget.

I think it's a combination of speaker placement, preamp and speaker also that lets the speakers disappear. 

Along with room acoustics and the speaker the gear used can be important.  I had Magnepan 1.7i's (they are dipoles) and they were a bit harsh and beaming initially (they come with resistors to tame the high end if needed).  I upgraded to 3.7i's and they were better/ smoother/less beamy.

I upgraded the amp's, pre-amp, streamer and added 2 subs and that helped make them open up the soundstage and added more 3D effect.  When I added noise control with high end switches with ground plane noise control and fiber and two CAD Ground Control boxes the speakers do a much better job of disappearing with most tracks.

Amazingly enough the amp used matters a lot as well. 

Agree with Maggie's 3.7i but they do need a high current amp and subs add a lot. . What sold me was listening to Back in the USSR. They do miss on the not to big mark however.