Happy Accident

@12many 

"... it really depends on the speaker and the room" 

  Yes!  

@antialiased 

I don't have the background to debate you on the basis of physics. All I can say is that others have found this not to be the case, me included. I trust my ears. 

@christianb5s4 

Some Wilson speakers provide a means of tilting the tweeters. I don't know the potential issues of tilting the entire cabinet. Someone more experienced may respond. 

@sgordon1 

Thanks -- good suggestion! 

@doni 

I'm glad you've found a way to compensate for that placement. 

@newbee 

Like me, you've found that experimentation can yield big rewards. 

@stuartk I was surprised to read in Jim Smith's "Get Better Sound" book that he says he has often found that if the distance between speakers (tweeters) is roughly 83% of the distance to listening position that produces the best sound.  I guess he would know with all of his best in audio show awards and thousands of setups so i moved away from the equilateral triangle as you did and had the same "accident" (well, not accidental)!  Sounds like you stumbled on much the same thing although your measurement is to the point where the tweeter axes cross behind your head.  

@stuartk , There is no reason you should not be able to make your current situation work. Your seating will be further back in the hall, images will be smaller but that is all. 1st off the image should never extend beyond the speakers unless there are phasing tricks being used like in Roger Water's  Amused to Death. The effect of imaging beyond the speakers is due to poor control of early reflections off the side walls. Some sound absorption is in order. Point the speakers right at your head. The next problem that affects proper imaging is imbalance between the channels. Your brain locates noises by volume and phase. If the 2 channels do not have the exact same frequency response curves the image is smeared, out of focus as some frequencies are louder in one channel than the other. No two identical loudspeakers have exactly the same response curve. Then you really screw things up by putting them in different positions. Now each speaker sees a different acoustic picture. I demonstrated this to a friend just yesterday. He had heard my system and wondered why his could not create a similar image. I measure each channel and showed him the curves and in the midrange they were wildly different up to 10 dB apart in places!  The only way to contend with this is digital EQ where you can adjust each channel independently to match within a dB from 100 Hz to 10 kHz.  He is going to get a MiniDSP SHD digital preamp which can contend with this problem at a level he can afford, appropriate to his system. 

The speaker and room are parts of the same organ. There are some rooms you are never going to get a decent image in. Both speakers need to see identical but mirror image environments as a starting point. The more variation there is between speaker positions the more impossible things become. Windows in particular are a major problem. They resonate like drum heads at frequencies that vary depending on the size of the window and stiffness of the pane. I spent three grand having a window removed. What a breath of fresh air that was. 

In short, the best imaging requires symmetrical speaker environments with close tolerance loudspeakers, proper acoustic management and absorption at early/first reflection points along with digital signal processing to touch things up. Anything else is wishful thinking or shear luck. 

@wyoboy 

I have nothing against stumbling into something good!  

@mijostyn 

The system is in our living room. We have large windows but I have no desire to remove them as we live in a conifer forest and I enjoy the view too much. My wife would not welcome room treatments and I can't fault her for that. If the improvements I'm experiencing are due to sheer luck, that's OK. I have no complaints!  

Women can not change the laws of physics. Well, maybe they can just not when it comes to audio. There are some very pleasing absorption panels. Ask the wife to pick a motif. They love doing that. A digital preamp with room control is your best bet otherwise. 

I understand the view thing. We have huge picture windows in the kitchen where my wife spends most of her time (bird watching). My system is in a theater room which needs to be blacked out as much as possible. The room is painted a very dark blue. Putting a window there was the biggest mistake I made designing the house. I though black out blinds would handle it.....not.