Setup Speakers Along Long Wall?

Check out the posts that mention AES48. My gear supports this so I use 15 foot Benchmark XLR’s that are low cost and sound excellent with this supporting gear. If If I was able to put a hole through a Livingroom wall I would use 50 foot XLR’s to get my rig completely out of the room.

Luxman gear, for example, does not support this standard and I would not use my Benchmark XLR’s with that, nor would I keep my amp(s) so far away from the preamp. First of all it would be very expensive to buy commercial grade XLR’s and I do not have confidence it would be good. Pro gear such as Weiss, Benchmark, CODA, and I think, Bryston support this.

One thing I noticed with LONG wall speaker placement in my Livingroom was that the speaker just 1 foot from the front wall was OK. I think this is because I have 7 feet to my left side wall and 5 feet to my right side wall. That right side wall is a partial wall that opens up to the family room. I also have 25+ feet of ceiling height in the Livingroom. All of the LONG wall space is what likely makes the sound work with a floor stander so close to the front wall.

In my last home, I used the long wall and ran the speaker cables under the floor. I’m a firm believer in not going long with interconnects, unless you are using XLR. And then only if there is no other choice. 
I did notice the lack of sidewall reflection and I grew to like it.

All the best.

JD

Nice system. A great looking room.

Looking at your system my guess is the subwoofers are overloading the room with bass. I assume with the subs turned off you do not have the problem with the turntable? I would start here. 
 

I am fortunate to have a large room. As @curiousjim points out, having wide spaces on both sides of the speakers can be good. You’ll probably need to heavily dampen  the front and  rear walls and the ceiling. It is worth a try… but I would first figure out how to stop the feedback. 
 

I’ll give it some more thought. I am sure with the additional info you supplied, there will be some folks that will have helpful suggestions.

If it were me in that space, I'd still try and utilize a short wall setup. It's a nice looking room with nice gear. I would first try a wall shelf to the side of the window for the TT, as it would be behind the speakers and possibly help with isolation from the floor, which is obviously suspended. If that still proved troublesome I'd look into isolation tables, to put on the wall shelf under the tt, from basic passive units, to high dollar active. Additionally, I'd really limit the subwoofer setting, place them outboard the speaker stands for space, and move the rest of the equipment low against the wall under the window. I see you've got some treatments, which is a good thing, many people overlook this crucial detail. I'd hazard to guess the interactions with the turntable are from the floor and not airborne, but I could be wrong there. You'll just have to try Jenga a bit moving stuff around to get the best compromise. 

I don't have cartridge feedback with turntable located as in picture.  I talked to the Wilson people and they prefer the speaker location as is, so I'm looking for a preamp with balanced out and 3 meter XLR interconnects.  My dealer suggested Whest, or Rega Aura and Wilson dealer suggested baby Boulder.  More bass traps on the way.