[woodnaudio]

What you describe sounds like your speakers are at least a little bit too far apart.  Try moving them a bit closer like an inch at a time and stop when you hit the spot where the soundstage is more real and there is none, or much less of this, going on.  Mark that spot with tape and try to go a little further in to hear what happens.  Then, go the other way again to make sure you've done the best with this that you can.

This was going to be my next step. I have some leeway with the listening position as well, so can play with that.

[TJHUB]

Currently running Linn Ninkas, but these are temporary. I have a pair of Omega Junior 8 XRS with Alnico drivers coming soon. They are setup along the slightly longer wall. Listening position is centered and approx 3 feet from the rear wall (a pair of French doors).

The speakers are set approximately 2ft from the side walls and 3-4 feet from the rear wall. This seemed to best balance bass-treble.

I'm no expert, just an obsessed audiophile.  I have moved my speakers to so many spots, I could never remember them all.  I will warn you against conventional wisdom when setting up your speaker and listening positions.  For example, my current room has my speakers closer to the room corners than most would try.  Putting my 4" thick, open back panels in the corners to function as bass traps and absorbsion was magical.  Moving the speakers out into the room just sounds worse.  I also found moving the speakers as little as a half inch can really affect the sound more than you think, but this is not true of all speaker positions.  I think you're wasting your time tweaking things prior to at least minimal treatments (corners behind the speakers, and 1st reflection points).  Your listening position could be closer to the wall behind you if it's treated.  I was around 24" at one time with great success.  The French doors could be problematic for you unless open.

Moving the speakers affects a lot: imaging, clarity, and bass response, etc.  The trick is to find the best balance of all of them.  Regarding your image issues, don't forget toe in on the speakers can really affect the center image, and various speakers work best at different amounts of toe in.  My Salk speakers throw the best defined imaging with a lot less toe in than my previous pairs of B&W speakers. 

I'm not saying not to try things now, but please expect to move everything again when you start adding treatments.  Make little changes and make notes or you will get lost in the woods...trust me.  And try not to focus on one or two aspects of the sound, or you will realize days later you made some things better, but ruined other aspects of the sound.   

[JLM]

You might consider introducing a slight skew to listening setup (not a symmetrical arrangement).  Like 30 degrees/60 degrees from adjoining walls.  Moving speakers/chair costs nothing but your time.  The value of a good (size, shape, insulated, treated) dedicated (available whenever you want without furnishing compromises) listening room can't be underestimated.  Without such a room (a true luxury for many), you might want to seriously consider headphones.  Have seen way too many over buy gear for a given (crummy) room.  For a room such as yours I wouldn't invest more than $1000 USD in the system (any treatments included). 

[woodnaudio]

You might consider introducing a slight skew to listening setup (not a symmetrical arrangement).  Like 30 degrees/60 degrees from adjoining walls.  Moving speakers/chair costs nothing but your time.  The value of a good (size, shape, insulated, treated) dedicated (available whenever you want without furnishing compromises) listening room can't be underestimated.  Without such a room (a true luxury for many), you might want to seriously consider headphones.  Have seen way too many over buy gear for a given (crummy) room.  For a room such as yours I wouldn't invest more than $1000 USD in the system (any treatments included).

I will try a slight skew... is the idea to offset reflections such that they have less opportunity to create modes or nulls?

I have a planar magnetic headphone setup that I like quite a bit. Once I get this system dialed in to where I like it, I’ll sit down and try and do a comparison with the headphones.

Too late on the spending... 

[JLM]

The idea was to randomize mid/high frequency reflections.  But any skew requires a compromise in providing decent distance for speakers and listening position from walls in a small room.  In a small/square room it'll always be a matter of choosing the lesser of evils.

With a nice pair of headphones available in-room listening under those conditions might best be relegated to background or casual listening.

Too bad on the spending, lots of really good sounding gear can be had on a "Cheap and Cheerful" basis that frankly would be overkill for your room.

[jtcf]

My room is squarish also 16x17 with 8' ceiling.It will never be perfect,but it sounds pretty damned good now since the addition of 4 subs and GIK bass traps.The corners are trapped from floor to ceiling with 6" rectangular traps and one extra thick 'monster trap' behind the rack in the front wall.This is also my living room so it does take some thought to balance the aesthetics.A possible solution for the french doors are panels on stands that can be moved to the side when not needed.

[woodnaudio]

With a nice pair of headphones available in-room listening under those conditions might best be relegated to background or casual listening.

For one type of listening, for sure. I think there's a qualitative difference in experience between headphones and 2 channel speakers that, at least in my experience, hasn't been bridged. I very much enjoy my MrSpeakers Ethers (with a Chord Mojo DAC and ALO Audio Continental v5), but even with the weaknesses in the room as is I still get a sense of enjoyment that is enjoyable in its own right.

Too bad on the spending, lots of really good sounding gear can be had on a "Cheap and Cheerful" basis that frankly would be overkill for your room.

Oh, I don't know about that. While I'm sure there are many enjoyable setups that would have cost less, you never know until you get that equipment in, no? I'll be the first to admit that sometimes I like / spend money on items that represent an idea / ideal... and that's certainly the case here. I just find the notion of a low power tube amp with high efficiency crossover-less speakers *interesting*, and something I'd like to live with and explore for at least a while.

Besides, there's one more room in this house that will eventually "need" an audio system.

[woodnaudio]

The idea was to randomize mid/high frequency reflections.  But any skew requires a compromise in providing decent distance for speakers and listening position from walls in a small room.  In a small/square room it'll always be a matter of choosing the lesser of evils.

I think what I am going to do is experiment some more with the current room layout and Cardas-based speaker positioning (http://www.cardas.com/room_setup_square.php)... after which I'll try on the diagonal. I'll use my headphone setup as a reference for tonality. Once I settle on something that seems to be the most enjoyable compromise, I'll look into measurement to take a principled approach to filling in any perceived gaps.

One thing I'm not clear on for diagonal room setups is... do the standard treatment guidelines for first reflections + bass trapping still hold? I can't imagine why they wouldn't, but what do I know?