FWIW, I think you most often have two choices when setting up bipolar, or a lot of panel speakers. You can emphasize an atmospheric (huge) soundstage or a very detailed or precise type of imaging which might loose a bit of the huge but pick up some precision and a sense of depth of image not otherwise available.
In the first it is all about how you treat the back wave - how it hits and bounces off your walls and to what degree it is attenuated.
The second is determined by how you receive the direct signal, including how it reflects off the side walls, floors and ceilings, as well as how flat the frequency response is, and whether or not it is best heard on or off axis. I've heard very few speakers, but there are some, that sound best on axis. For example, many speaker manufacturers of traditional boxes recommend that the speakers are firing straight forward.
Occasionally, and incident to the rising of a blue moon, you can effectively set up a bi-polar speaker which results in great width, height, and depth of sound stage and have great precision as well. Good luck...........
What I would do in your place to determine what is possible would be to set up your speakers optimally for the precision/tone effect by deadening the back wave and taking that out of the equation. Then you would have a tone you could live with - i.e. no high frequency caused fatigue. After that remove the deadening materials used on your speakers or walls and see how much the back wave really alters your sound stage. You might be surprised (or not). But you could then start to make incremental changes in the surfaces of the rear walls and adjacent side walls to get that huge soundstage effect you are looking for without getting the fatigue back.
In audio as with life, it is all about compromises....
BTW, I agree with the first poster, you have stuff in the signal chain which could certainly help produce the problems you are complaining about. Years ago I solved a similar problem by returning to IC's and speaker cabling that did not emphasize high frequencies as yours might do.
In the first it is all about how you treat the back wave - how it hits and bounces off your walls and to what degree it is attenuated.
The second is determined by how you receive the direct signal, including how it reflects off the side walls, floors and ceilings, as well as how flat the frequency response is, and whether or not it is best heard on or off axis. I've heard very few speakers, but there are some, that sound best on axis. For example, many speaker manufacturers of traditional boxes recommend that the speakers are firing straight forward.
Occasionally, and incident to the rising of a blue moon, you can effectively set up a bi-polar speaker which results in great width, height, and depth of sound stage and have great precision as well. Good luck...........
What I would do in your place to determine what is possible would be to set up your speakers optimally for the precision/tone effect by deadening the back wave and taking that out of the equation. Then you would have a tone you could live with - i.e. no high frequency caused fatigue. After that remove the deadening materials used on your speakers or walls and see how much the back wave really alters your sound stage. You might be surprised (or not). But you could then start to make incremental changes in the surfaces of the rear walls and adjacent side walls to get that huge soundstage effect you are looking for without getting the fatigue back.
In audio as with life, it is all about compromises....
BTW, I agree with the first poster, you have stuff in the signal chain which could certainly help produce the problems you are complaining about. Years ago I solved a similar problem by returning to IC's and speaker cabling that did not emphasize high frequencies as yours might do.