Speakers with no rear wall, better or worse sound?

It would help if we knew what type of speakers and amplifier you have.

My current speakers are Avalon Opus with all Spectral electronics (DMA-250 amp/ 30SS pre). I am currently considering Magico speakers for which I would be willing and eager to optimize the room. I had a reputable dealer indicate that one needs a wall behind the speakers, albeit 4-5 feet back. I felt that having essentially no wall behind the speakers (i.e. no chance for reflected sound mixing with direct) would be preferred; but I am not the expert. I have pretty good imaging and excellent soundstage depth (width is reasonable). I have carefully consider first (side) wall reflections, floor reflection, etc. in the placement of the speakers.

What I have found, while setting up both panels and boxes is that the existence of a wall behind the speakers is best so long as your speakers are about 5+ feet away. Adds a bit of 'body' that can disappear if there is nothing there provided the surfaces match the speakers design. Exactly the opposite for listening chair. I greatly appreciate dead space behind a chair (or at least 5 feet from a wall). I can do with out side walls, :-).

The 'body' component is I believe the strongest supporting argument for having a rear wall. Of course we have the floor, side walls, and ceiling for some level of body. I was wondering if a good recording is to accurately reproduce a 'live' sound, it should also include the recorded characteristics of the room or recording studio. Mixing in different listening room characteristics adds some coloration (which may be desirable), but it is not accurate reproduction. I do realize that a completely dead room lacking no 'body' can lead to an equally dead or flat sound. One may say "whatever sounds great to you is fine." I would usually agree with this. My point in this thread is that it is impractical to (reversibly) add or subtract walls to find a preferred listening character. Fundamentals of acoustics/physics must play a role in understanding and addressing the limitations of any room that has not been purpose built for listening.

Problem is that 'accurate reproduction' is such a moving target, especially when most recordings are hardly 'accurate reproductions' of a live event in the first place. Most recording efforts to produce accurate recordings come from classical music department but it only works there when well engineered performances are small scale which seems to overcome some of effects of the compression and downsizing of larger orchestral events. So it is a compromise. Even most soundstaging effects having their orgins in the recorded music, as opposed to set up, are artificially recreated by mic placement which often gives undue prominance to some instruments which is something you never hear in concert. But it sounds nice :-).

So, I would also make a case for the thought that 'if it sounds good to you, then it is good' because sounding 'real' is virtually impossible anyway, and faithful reproduction of what is on the disc of the majority of the music you listen to may not really be what you want to hear. The exception to this may be the few really anal audio enthusiasts who really do want a perfect chain, cradle to grave and they listen to principally train wistles and jets taking off. :-)