Speaker positioning and center image depth

@blisshifi, my impression is that soundstage depth can either be dominated by the room or by the recording, the latter being preferable but generally more difficult to accomplish.

First looking at the room as the constraining factor: As a ballpark first approximation, it seems to me that soundstage depth is related to the distance from the speakers to the wall (or equipment rack, or TV, or whatever) that is behind and/or in between them. My untested observation is that soundstage depth often seems constrained to twice the distance to the reflective surface between and behind the speakers. So if the speakers are out three feet from the wall, it seems to me that soundstage depth tends to extend to about six feet - which is cool because it is perceived as extending beyond the physical room boundaries, but imo there is significant room for improvement.

Diffusing, re-directing, or broadband-absorbing the first reflections off the wall behind the speakers (and avoiding having the equipment rack or TV there) can help to "unmask" the soundstage depth cues which are already on the recording.

Also, well set-up (i.e. far enough out into the room) bi-directional speakers like the Borresens/Raidhos, Quads, and Maggies you mentioned, have reflection characteristics which can be exploited to shift the perceived acoustic space from "playback room" to "recording venue", whether the recording venue cues be real or engineered or both.

Duke

How the speaker images should be entirely up to the recording. This assumes that the equipment is up to the task and set up correctly. If a system images the same way regardless of the program source it is either not up to the task, is not set up correctly or both.

I shall throw another hand grenade while I am at it. Painfully few of us have ever heard a system that images correctly. I think many systems are capable of a satisfactory image but are not optimized to perform at that level do to problems inherent with speakers and room issues. 

@audiokinesis Your post is thoughtful, and I appreciate that you have not (yet) redirected the conversation in any way to focus on how the role of subs can manipulate the stage (for better or worse), yet of course that is a whole other direction for discussion. I for one would certainly enjoy learning about tested observations / white paper between speaker depth and stage depth, but I agree largely with what you say, as long as a speaker can actually image well. And for sure, managing the reflections and reverberations are as important as the positioning itself.

@mijostyn Both great points, self-awareness and humility go a long way here.

@blisshifi , if we can trick the ear into accepting the spatial cues on the recording as being the more plausible "package" of cues, rather than the spatial cues inherent to the playback room, we can achieve that elusive "you are there" experience (assuming a good recording). As long as the playback room’s acoustics are perceptually dominant, we are limited to a "they are here" presentation, which admittedly can be quite enjoyable, but "you are there" can be memorable. How to implement this concept of course depends on the system specifics, but I wanted to emphasize that "recording cues dominate" is a different paradigm from "playback room cues dominate".    

And of course all of this is assuming the speakers can actually image well to begin with.

Duke