Experimenting with Speaker Room Placement

My room is similar to yours, and I did the same thing initially.
I ended up placing my speakers at the middle of the room-using the shorter wall. The sound is very good, with almost no bass nodes.
It also looks good, as this is the division between living room and dining room.
B

FWIW, your bass problems are likely a problem with placement of the speakers in a bass node. Or your listening chair is placed in a bass node, or both.

I have a 13x19 ft room, have the speakers on the short wall out about 66 inches and about 96 inches apart. My chair is about 48 inches from the back wall. If I move either my chair or speakers back towards the wall behind them I get a bass increase that can be very noticible. I also have noticed that toe in as well as placement affects the potentially  'fatiguing'  issues you refer to. I have side walls well damped with bookcases, drapes etc to kill sidewall first reflections. IMHO getting those speakers well out from that back wall is a major issue. 

I also tried the long wall. I found the sound rather sterile. I think it killed the natural room acoustics.

I found this with several sets of speakers, none of which were yours.

Nearfield or not, short wall or not can largely be personal preference, but it can also can be somewhat dictated by your equipment -- most of all speakers.  For instance, tower speakers often require a greater listening distance so their drivers, which can be spaced farther apart, have enough space to come together -- not as much of an issue with something like 2-way monitors. 

Personally, I'd put the speakers along the short wall if possible as you can listen in the nearfield or not, and you'll have more freedom to pull your speakers out further into the room (also need to give them some space from the side walls).  This not only helps improve soundstage depth but can also help mitigate bass overload, which may be what you're experiencing.  If you haven't already done so, try pulling your speakers -- especially the towers -- 3, 4, or even 5 feet out from the wall and you should notice a significant improvement in tonal balance along with possibly a greater sense of a 3D soundstage.  It may also help your speakers disappear more as a sound source as you get them further away from reflective boundaries.  Before I had a dedicated listening room I used to pull my speakers out for serious listening and put them back to avoid divorce.  Some things are just worth the effort. 

Other things you can try are toeing the speakers in more toward the listening position or plugging the port if the speakers have them (although this doesn't work well with many speakers).  If you're on a suspended wood floor you can also try getting some marble or concrete slabs (and/or audio oriented footers although these can get more expensive than slabs) under your speakers to help decouple them from the floor.  Also, don't place the listening seat directly up against a wall as the reflected sound can muddy things up considerably -- even a few inches can make a big difference. 

I'd think with your size room this should be a manageable situation to a good degree even without room treatments if you have placement flexibility.  That said, I don't know of a room that wouldn't benefit significantly from the use of some well-placed treatments (assuming no electronic room/speaker correction is being used), so that should eventually be a part of your plan regardless.

Just some thoughts off the top of my head but hope some of it helps, and best of luck. 

Long wall always everywhere I've ever been. It's the best way to avoid side wall reflections and overwrought corner reenforcement. 

12 feet is too far. 7...8 feet is perfect.

Oh, no, not again! This topic has been discussed to death. Please use the search function!

Okay I do appreciate all the suggestions I realize it is a topic that has been discussed before even yesterday was an interesting topic about possibly bipolar or omnidirectional speakers like the ohm Walsh that might be a possibility in my room as well. 
Pulling the speakers out from the short wall at least 5 ft helped with Clarity but those side wall Reflections are still getting me 

Something to try to minimize the sidewall reflections. Toe in the speakers until the axis of the speakers cross well in front of your listening position. If that doesn't effect a reduction in sidewall reflections, your problem might just not be sidewall reflections at all. If it does help you might consider what you might do, acoustically speaking, to reduce the reflections. 

closer to long wall down to half-foot is fine -- wall rug behind them will kill reflections from back wall. 
i'm 6' from my Aerial 10T and they're 7' apart.
I liked it more than speakers 6' apart and I'm 8' away.
I prefer distance between speakers to be larger than distance from speakers.
Room is 14x17

I have a dedicated room that is 27x16x12. I just bought a new pair of Usher X-Towers. I used to use the rule of thirds for my prior ushers, but the x-towers produced way to much bass out 9’ from the back short wall. The room is treated with sac tube traps in each corner, and gik super bass trap in the back and multiple 1st reflection tuning traps. 

I went to the Cardas site and used his formula for placing speakers from the back wall and side walls. Much better, the speakers are around 80” out from the back wall and 50” from the side walls. Now the listening chair positioning, Cardas doesn’t go over that. I went thru Jim Smiths book and positioned my chair 33” from the back wall. 

Sounds great now.

I truly believe that stereo listening is best when NOT far away no matter how large room you have, because I haven’t heard good sound yet n very large rooms unless more than pair of speakers used and properly matched. In this situation you can only rely on best trial error possibilities.
I love headphones performance so have large speakers in relatively small listening area for that reason!

I have a room almost the same size as the OP's and have experienced very similar problems in set up. I too now have my speakers on the long wall. I started with them on the short wall and after almost wearing out the carpet from moving them around so much, I finally tried them on the long wall. Better this way but still not entirely satisfying. I have numerous room treatment pieces and have gained some improvements by using them. 
Personnaly I think that the house may be improperly orientated with the earths magnetic fields thereby causing interference. Perhaps a visit from a Shaman to do a purification is needed.
Listening near field certainly provides the most clear, clean and detailed presentation but feels unnatural for me. I am more used to and prefer a more mid to far field position. 
I contacted GIK for a room analysis and after providing them with drawings, photos and conversation they replied with responses such as "well you could do this, or that". Not really what I expected from them as I though they would provide a more specific "road map" of how to treat my room.
So I am still in the same boat as the OP and am interested in specifics from others that have had a similar problem and how it was solved.  

Thanks Jadedavid and Czarivey. I will re-try the short wall - what do you guys use for your short wall treatments? You mentioned a 'wall rug' ? I need to treat the back short wall where the speakers are placed and the short wall from my listening chair, which unfortunately would only be about a foot or two from my ears - so need to do something for those reflections.  

I've also been reading more about possibly bipolar or something like Ohm Walsh speakers - so instead of a perfect image studio monitor approach, use an omnidirectional.  Or possibly the Vandersteen VLR right up against the wall. So as to speaker options, seems like there are other choices that may work to overcome these room problems. 

My rooms are furnished heavily with bookcases, drapery, venetian blinds and area rugs. So, reflections are pretty much a non-issue.
Barring that, perhaps hanging an area rug or a moving blanket(that would be a temporary fix to see if it made a difference.

B

As far as rugs go, there are numerous decorative plush throw rugs of many different sizes available at Home Depot or Lowes or at a Carpet retailer.
As for speakers, I keep reading and hearing good things about the Larsen speakers in situations like this.
Good luck on your journey.

Try using math to calculate the distances and fractions of the room.

I have my Magnepan facing down the long way..
Using 1/7 distance to the far wall, and 1/5 to a small barrier (which is a narrow wall behind which are set of closets between the door and the kitchen)
My speakers are at both with a distance of 45" from the windows.

This eliminates a lot of room reflections

You want odd fractions.. not even ones. And this is all at the driver face of the speaker. ignore the back of the cabinet

Buy Jim Smith's book Get Better Sound.
Read it, then read it again.
Get your positions of speakers and listening seat established.
Do room treatment.
Enjoy how much better your system sounds.
Enlighten others.

So you pulled the speakers out 5 feet and noticed better "clarity."  I assume that means the bass was less boomy and the sound was better balanced overall?  What is telling you side reflections are still a problem?  How far are the speakers from the side walls and how much are they toed in?  These two variables alone could go a long way to fix sidewall reflections if indeed they are causing a problem (see below for more).  What areas still don't sound right and what are you still looking to improve?  The more detail you give, the better advice you'll get here. 

As as far as going to bipolar or omni-directional speakers to deal with room issues, this seems a bit extreme IMHO. First you need to see if that type of sound, which is different from direct radiating speakers, even appeals to you.  As others have mentioned my our room does not sound overly problematic as it's very similar to mine and others here, so you should be fine with a little more help and effort. 

BTW, to find sidewall first reflection points and treat them, sit in the listening chair and have someone stand with a mirror against the sidewall near the left speaker.  Have them face the mirror directly toward the opposite (right) wall and walk directly along the left wall toward you, and when you see the left speaker in the mirror that is your first reflection point of the left speaker that you can mark with painters tape or whatever.  Keep moving mirror closer to you from that point and when you see the right speaker that'll be the first reflection point of that speaker on the left wall.  Repeat same thing from the right wall.  Try temporarily hanging a piece of carpet in those locations to see how it helps (or you can put something like a bookcase there as long as it's high enough).  You can follow the same procedure to identify first reflections from the ceiling and floor as well, which are also important areas to identify and potentially treat (a carpet or area rug usually takes care of the floor -- ceiling's a bit tougher aesthetically speaking). 

Again, I find long wall vs. short wall is very much a personal preference thing (assuming your room and speakers can work both ways) and you'll probably find yourself finding one or the other more personally satisfying pretty easily between sonics and how close you want to sit to your speakers.   FWIW...

tomcarr
Buy Jim Smith’s book Get Better Sound.
Read it, then read it again.
Get your positions of speakers and listening seat established.
Do room treatment.
Enjoy how much better your system sounds.
Enlighten others.

Whoa! What?! Back up! The speaker locations will change as you apply room treatments. That’s because the dynamics of the acoustic waves changes as you treat the room. What you have to do is use the speaker location track of XLO Test CD. Then you will be able to find the single absolute best speaker locations, assuming a given listener location, not some guesswork.

However, as room treatments progress the 3 D dynamics of sound changes. That’s why you have to re-establish speaker locations every once in a while with the XLO CD. Trying to find the absolute best speaker locations without the XLO Test CD, trying to do it by ear, is like trying to solve 3 simultaneous equations in 4 unknowns. 😬

In any case reverse the order of establishing speaker and listening positions and applying room treatments shown in the previous post.

I certainly don’t wish anyone to take this too hard but somebody, I won’t mention any names, is following the wrong....you know....

🐑 🐑 🐑

The distance from the "front" wall behind the speakers and the amount of toe-in are speaker dependent and one should start with the manufacturer's recommendations if any. Canton recommends 12 to 20 inches and no toe-in for my speakers. as well as the speakers and listening spot forming an equilateral triangle. I have found that 19 inches off the front wall and a listening position slightly further back work best in my room. My speakers are 96 inches apart and my listening position is about 98 inches from a line connecting them and about in the middle of the room. I have used the Isotek CD to fine-tune placement and toe-in and it made a big improvement.

Broadly speaking, the further you pull the speakers out from the front wall, the deeper the soundstage.  My room is 14'8" x 16'6".  Speakers set up on long wall.  A full 3' from the back of the cabinet to the wall behind.  Excellent depth.  If your speakers can do bass, you should still get plenty.  Admittedly, sofa is pretty much sandwiched against the opposing wall, but it works better than the conventional short wall setup.

Newbee and siox have it correct, as many others, at least in my experience. Jim Smith and Dennis Foley have very valuable info on this topic. Use the rule of thirds to start out with and go from there. A equal lateral triangle is a good place to start concerning your speakers and listening chair. . Plenty of room from your front and back wall, as far as speaker placement and listening chair. Move your listening chair up. This helps to give your sound a chance to fully develope. Diffusers and absorption will greatly improve the sound. First and second reflection points need absorption and possibly diffusion. Both on front and rear walls. In my experience, u want the room to be as deep as possible. It takes around 60' for a 30 hz note to develope. Vary few of us have that deep of a room. Cut that in half, then in half again. Lots of absorption on the rear wall makes your room "seem" deeper. I've heard it said an outside field, with no walls or ceiling is the best set up. Crazy.