Room Acoustics and Speaker Placement

You can also play with the distance of your seating to the speakers. Near or nearer field can minimize the sidewall difference. This might apply if you're in scenario #1 or #2.

@hilde45 If you look at the OP's pictures from a previous post, it will make more sense.

@OP - the numbers you quote look accurate and confirm what your pictures show, namely, that if you leave a reasonable distance from the right hand side wall and, allowing for the door, you have very little distance between the speakers. 

Google is our friend. 

Some stuff here also. https://audiophilereview.com/

@dcp20124 Thanks.

The critical things to know are the distance from speaker to listener, the distance from speaker to side wall to listener. You mention "the wall" but I don't know what that means. A diagram would help.

@hilde45 the wall itself must be around 12 feet. So I could position the speakers potentially 3 feet away from the right side wall leaving about 6 feet between the speakers. And for what’s it worth, the distance from the left side wall (basically entrance of the apartment) should be about 7-8 feet.  So more distance to the left side wall as compared to the right side. Hope this helps! 

@OP - Understood, thanks. (Mrs) probably won't be rushing to apply acoustic treatment but you will need some as the space is going to be very reflective otherwise.

Specific distances are needed to calculate reflection times.

@yoyoyaya actually the photos are a bit deceptive. The width isn’t as bad as it appears.  The width of the wall where I’m planning to place the speakers should be at least 10 feet if not more. 
 

and to your idea about moving the speakers to the dining area, I did consider but my boss (Mrs) doesn’t want dining table to be the first thing people see when they enter.. it’s an argument I know I can’t win.. lol

@OP The photos re helpful. Perhaps you could give consideration to relocating your dining area and placing the speakers on the wall in the picture that is marked "dining". The other two locations have very little width to accommodate speakers.

hey guys, thank you so much for all the comments and suggestions.  Definitely leaning towards option 2.  

hilde45 @jawfxr01  Here are some photos. they’re not perfect but hopefully gives you a idea. I have tried adding notes so you can understand the layout.  The wall to the left side of the speaker is where the TV would go.  The wall to the right of the speaker is basically the entrance to the Apartment.  

Been down the one sidewall road.  I noticed the bass dropout most of all.

No brainer....

#2...no back wall (the back wall in any proximity causes a lot of problems for a high fidelity listening experience)

side wall symmetry --> easily managed with pertinent predictable treatment at a future date (if wife permitted it).

1) speakers will be positioned such that it will only have 1 side wall. The other side will be open (dining area).

2) speakers will have both side walls (not equidistant) but no rear wall (my back will be towards the dining area). 

A picture of the setup would help a lot. If not, give us the

sidewall distance.

I agree with option #2 especially if you want to treat that space as a listening area.

@gano I only know this stuff because of kind people on this forum. So, paying it forward, bro.

@hilde45 you didn't direct at anyone, it just took me some time to digest your relevant and expert  quote and I felt stupid :) I directed it at me...

Oh also , as touched on above about side wall reflections. I rotate a SS amp on the side wall configuration and it really expands the soundstage and of course the volume. At this point the side wall and ceiling reflections  appear. Tube amp no problem, SS amp big problem. So the comments above from a couple members are very relevant and being familiar with their shares are meant to enlighten and not offend. I had that to experience that when I rotated in the SS amp. Hilde in particular is very well practiced at room treatment and very helpful to me for getting direction. Hope I’m not overstepping with my thoughts , as we’re here for a good time. Cheers , my Peers ! 

Hi , I have the same scenario. I started with home theatre using option #2 having a combination of Klipsch Heritage and JBL studio on Sound Anchor stands. I then went to 2.1 same layout. Over time the wife factor crept in and I went to option #1 with a Plasma TV in the middle. When I shifted from the open back to the side wall the sound suffered. I then went low power tubes on the side wall and have been able to cope due to heavy carpet , heavy tapestry drapes and a huge cloth sectional.  But I’ve longed to go back to the open back configuration. I must say however that late night listening to female vocalist with NOS tubes on the side wall at low volume was very enjoyable.  My room is 17x 27 but the actual listening area is 17x17. The open back is a hardwood floor dining area. I just had a pair of Rogue M-180’s freshly brought up to Dark spec and the Tekton DI’s arrive Monday. I’m going back to #2 and look forward to room symmetry and room to breathe. I hope my ramble makes sense. Regards , Mike B. 

@gano I didn't direct my comment at you; I was just trying to add to the conversation. I'd say you did this one to yourself! Peace.

@hilde45 way to make me feel stupid 

Another vote for option 2. 

Also helpful: https://pmamagazine.org/early-reflections-101-the-first-10-milliseconds-that-make-or-break-stereo-imaging/

What Are Early Reflections?

While a domestic room’s total sound decay ideally lasts between 200 and 500 ms for stereo playback, early reflections occur within the first 40–50 ms, as illustrated in Figure 1. In domestic-sized rooms, our primary focus is on the first 10 ms—this window typically includes initial sound reflections off walls, the floor, ceiling, furniture, and other nearby surfaces. Because these reflections arrive so quickly, the brain integrates them with the direct sound—a phenomenon known as the Haas effect or precedence effect. Reflections arriving later than ~10 ms, or within 10 dB of the direct sound, can be perceived as separate echoes, which may degrade clarity.

Process Flow for Room Treatment

1. Address Early Reflection Symmetry

• Why First? Early reflections occurring within 5–20 milliseconds of the direct sound significantly affect imaging precision and tonal balance.
• Key Principle: Asymmetrical reflections can cause image smearing and coloration.
• Solution: Use absorption or redirection (via diffusers or angled surfaces) at the first order reflection points on walls, ceiling, and possibly the floor.

2. Control Decay Time in the Bass Range

• Why Second? Bass frequencies have longer wavelengths, making them harder to control and prone to modal ringing which can also affect its harmonics in the midrange.
• Key Principle: Excessive bass decay obscures clarity across the spectrum, masking fine musical details.
• Solution: Use bass traps in room corners and boundary intersections to reduce low-frequency decay to the desired target (< 500 ms).

3. Shape Mid/High Frequency Decay

• Why Now? A process that skips early reflections means that decay time is ambiguous as it contains early reflection peaks which smear imaging. High frequencies can be tuned more effectively after early reflection peaks are tamed.
• Key Principle: Mid/high decay that’s too long creates echo and lack of detail; too short creates a dead-sounding room.
• Solution: Use a combination of absorbers and diffusers to fine-tune decay time characteristics.

4. Finalize with Frequency Response Equalization

• Why Last? Should you start by equalizing frequency response, then decay is polluted by EQ changes done before it, and with every absorption panel change an EQ re-do is necessary. EQ must be applied after the room’s physical response is stable.
• Key Principle: Premature EQ results in corrections based on unstable room conditions.
• Solution: After acoustic treatment is finalized, apply EQ to flatten any remaining minor response deviations.

Why This Order Matters:

• Skipping early reflections means decay measurements include early energy peaks, skewing results and degrading imaging.
• EQ before treatment causes circular adjustments, as every panel or trap affects response and requires re-EQing.

Still no answer about the distance to the sidewall. This is a critical piece of information.

The strongest reflections caused by speakers in a listening room are called “first reflections”, which are a single bounce off walls, ceiling, and floor before arriving at the listening position. However, the human brain is adept at recognizing direct sound despite the first reflections, provided two things happen: 1) the first reflections contain the same or similar frequency content as the direct sound, and, 2) the first reflections arrive within about 10ms of the direct sound.

By their nature, first reflection path lengths are longer than direct sound path lengths; if they are too long—in other words, longer than 10ms, which equals 135″ longer than the direct path length—they become detectable as echoes and deteriorate the stereo sound quality. (Speed of sound is 1,125 feet/second, so 1 millisecond is 1.125 feet, which is 13.5″.)  First reflection path lengths of 135″ longer than the direct sound path may benefit from acoustical treatment (i.e. redirection, absorption) to avoid being heard. Diffusion on sidewall first reflections has been shown to reduce speech intelligibility. Our preference is to use flat reflection, angled reflection, or absorption....

To Treat or Not To Treat Sidewall First Reflections

When considering sidewall treatment options at the first reflection points, I try to balance a few factors: how much longer are the sidewall’s first reflection path lengths compared to the direct path length; the average decay time for the midrange and high frequencies; a person’s preference between strong imaging or a wider soundstage.

https://pmamagazine.org/the-room-acoustics-series-reflecting-on-sidewall-first-reflections/

Challenging scenario. I think rear wall is vital to imaging

and bass support etc but,… how to omit side wall reflection?

perhaps sound dampening? With both side walls you’re still dealing

with unequal reflection timing, so how do you address that? And

you wont have the imaging that you would with rear reflection.

challenging scenario. You didn’t mention speaker separation 

distance or whether you will treat it as near field listening.

good luck and all the best.

Number two is the better of the setups. You might get some unwanted ambient sound from the dining room in setup 2 but that's better than having the speakers in, effectively, two different acoustic environments as in option one. 

Option 2. 

You can differentially decorate the sidewall the at is closer to the speaker to absorb a bit more. Open behind is great, since the great depth will eliminate rear reflections. And as a bonus, it will probably sound better in the dinning area. 

I think you're going to like option #2.  Having an open area behind the listening position can be very constructive.  No unwanted reflections.  Good luck and let us know how it works out.  

https://youtu.be/zx8b9zxJt4k?si=lp-c_H62uWErZ4ho

https://youtu.be/08ZNrdypSHk?si=R1bzPC7UktSD4W0a

These  videos may help you with sound stage vs speaker’s  tow in and placement.

https://youtu.be/dNdhDCv4mzc?si=d6eBoecaFdTSrvDI

Adding some sound absorption at the first reflection point on the near sidewall should help alleviate any concerns about L/R balance with having differing distances to your sidewalls.  I’d always prefer an open back wall condition over a close one.

As long as you don't hear a shift in the center image you should be fine. Hopefully the one that's closer to the side wall isn't very close.

The distance to the sidewalls is important. If they are far enough away, then the asymmetry doesn't matter. 

 @ozzy62 & @immatthewj Thanks guys!

With option 2, the side wall on the left will be farther away as compared to the side wall on the right.  Is there anything I can do to minimize the skew? Would toeing in help?

Neither is ideal. But if those are the only choices I'd go with option #2.

I am not a guru, but although I’d think experiment with both if you have the outlets available (or enough speaker cable) I’d THINK having the sidewalls but having whatever is in the dining area as a rear wall would be the better option.

I’d THINK that with this option, your reflection points to  the side would be equal, and if they were not, I would also THINK that your left/right balance would be skewed.  As far as the dining room where the back wall would be, at least there will be stuff back there for diffraction and I would also THINK it might be advantageous to have that as opposed to a reflection off of a back wall that was closer.