You've got a tough situation, especially with the glass wall on the right - that is very reflective. The masonry wall is probably less so, especially if the masonry has any texture.
The good thing is that you can experiment with acoustics very inexpensively. Find some pillows, cushions, or even a thick bedspread/comforter and position them on each wall, halfway in between the speakers and the listening position. The items should be at listening ear level. This is the primary reflection point. (If you've ever played pool or billiards, think of calculating the angle of a bumper shot.)
My bet is this will improve the sound considerably.
If it works, the hard part is translating the experimental placement into something more suitably permanent. However, there are companies that sell room treatment materials. Continued experimentation will probably improve things further.
I wouldn't worry about changing any equipment until you've settled on a final configuration for the room acoustics.
I assume that you have done all the measurements perfectly. One method is Jim Smith with Get Better Sound. It is not mathmatical but is acoustical. Money well spent. Once perfectly positioned then room treatments will help balance the frequencies. I have a problem with channel tracking at very low volumes with my preamp which will favor the left at very low settings. I am getting new matched tubes. Just a thought. Good luck.
My experience with VAC is a very vivid and transparent sound, but Vac can sound glassy in some systems. It is not my choice in electronics.
It is difficult to give a recommendation about your room without more information.
You don't need to scientifically measure your room, use your ears. Your ears told you something is wrong and your ears will tell you when it's right.
Using things you have around the house to experiment with is a good idea.
Another vote for "Get Better Sound" by Jim Smith. Easily found here and on the web, well worth the money.
Might want to cover the brick wall with a comforter or something...same with the glass.
Bring your speakers a few feet of the back wall as well. Make sure your listening spot is equidistant from both speakers. Might want to try a bit of toe in or out on the speakers as well.
Most of your gains, though, will be from taming the acoustics of the room. That's where Get Better Sound comes in.
Look into to "Master Set Speaker Placement". Worth a try.
I presume you've done this, but if you haven't, measure to make sure the speakers are both the exact same distance from the center of the sweet spot.
If both side walls are quite reflective, then symmetry becomes more important. A strong early sidewall reflection can pull the image over to that side, so you want the early sidewall reflections to be either symmetrical or minimized.
Something that has not been studied much is the effect of a diffracting feature, like the vertical edge of a bookcase. A feature like that can mimic a secondary source, and pull the image over to that side.
Sometimes a "hole" (like a hallway) on one side of the room can pull the image towards that side. I do not know what mechanism is responsible for this, but I suspect the ear/brain system senses where the room boundaries are and might, under some circumstances, "mold" the perceived location of sound images accordingly.
Increased toe-in might be useful. The Merlins may not be the ideal candidates for this sort of setup, but (since it doesn't cost anything) you might try toeing them in severely, such that the axes criss-cross in front of the listening area. This will minimize early sidewall interaction.
Finally, if all else fails, try pulling the right speaker forward an inch or two. The slighlty earlier arrival time may offset whatever else is going on in your room.
I had a similar problem. My room is approx 13'x24' with 9 foot ceilings. My speakers are on one of the short walls. I have windows across one of the long sides of my room. The other long wall is drywall. I bought bookcases with glass doors for the side with the drywall so that the room was more balanced. This worked well and gave me a place for more books. I then used tube traps in the corners and put a very deeply carved wooden screen on the wall between the speakers. It is not perfect but it is a lot better than it was.
This is a link to my room photos:http://www.photogan.co.il/audio/
side walls distance: 3.6m (11.8 feet)
front rear distance: 7.0m (22.9 feet)
ceiling height: 2.6m (8.5 feet)
Acoustics can be very tricky, especially in asymmetrical rooms. Your room may look symmetrical, but the reflectance of glass and concrete at various frequencies is differentconcrete being more linearhence the bias in the image towards the left. The obvious thing to do is to use the balance control on your preamp. One half to one dB may be all it needs to center the image. Toe-in will help only for the high frequencies leaving mid to low still unbalanced.
Try hanging a thick comforter from the areas on the side wall where first order reflection is, that is the worst reflection it will be 45 deg off the speaker cone. If that helps you either need defuses or absorbers there. Wall hangings like rugs, and stuff help or just search for sound panels there are easy to make.
Also check the position of the speakers in the room if look on Vandersteens site in one of the owners manuals he gives you a way to measure where the speaker should be in the room that is step one. if they are to close to a wall that can cause all types of trouble.
There is a always a balance between acoustics and function / ascetics in a room.
couple thoughts. I have a somewhat similar goofy room and found after much experimentation that I was able to "position" my soundstage by having different levels of toe-in. I tried for symmetry but always was skewed. GOt my distances right and played with toe in on one side and than the other. Found I could get what I wanted with roughly 3 or 4 degree difference. YMMV. On another note I would be really surprised if edge diffraction is at play here when so may reflections can have a field day. If I recall correctly the equations indicated to me that sound diffraction in something like this should be about nothing. Have to think but off hand I doubt it.
From experience, those wall reflections are most likely the cause of your 'hard' sound, not your gear or cables.
With your speakers being rather far from both sidewalls and roughly equidistant from them, I do not think the acoustic-reflection differences between the two types of walls are enough to explain why your image is pulling to the left.
You are instead hearing the reflection off the top of your large coffee table, which is located left of center.
Best of luck!
Green Mountain Audio
You have a wonderful system, but based upon the photos, your speakers are ill suited to your room. Specifically, the wide dispersion tweeter of the Merlin are a problem. As pointed out by others above, it's bouncing sound off of every hard surface in your room (the glass doors, concrete walls, tile floor and coffee table). Due to the different reflective qualities of each surface the combined direct and reflected sounds won't cohere. This will be especially problematic with a high resolution design like the Merlins.
You could try various acoustic room treatments to try to eliminate, or at least lessen, the reflected sound and that could work very well if you're willing to convert your living space into an audio room with audio room aesthetics. The other possibility is to get a speaker that works with the room as opposed to fighting the room. My recommendation is that you consider something in the Audio Note line. Because they require corner placement they will load the room differently and I believe in your case more evenly. You'll still require acoustic treatments, but they can be larger limited to the corners containing the speakers. I'd also recommend getting a rug. The Audio Note line will also work well with your existing electronics. Please note that by design they are not studio monitors like the Merlins. They are more relaxed sounding.
Many good responses here. The cause has very likely been touched on somewhere in the responses. But let me just add one other possibility. Have you had your hearing checked? This may sound like a joke, but it's very common for the sensitivity of one ear to vary from the other. One more reason the elimination of the balance control on audiophile equipment is just plain stupid.
A picture is worth a thousand words. I would say your channel imbalance is due to your furniture. You have the large end of your sectional sofa directly in front of your left speaker and the other side of the room is wide open.
Man, where to start?
First of all, there are MANY hard, reflective surfaces in your room. That is the cause of the hard sound you are describing. And slap back echo from a lively room will contribute to confused imaging and soundstaging. Early sidewall reflections can also cause the image shift you hear. Don't spend another penny on electronics until you have invested some time and money on room treatments. Free standing room tune panels (or variants) at the first (and second possibly) sidewall reflection points, an area rug over the floor, corner tunes in the uppermost corners, and some traps or panels directly behind the speakers. That should get you started.
Get "Get Better Sound" by Jim Smith. You may have micro-misalignment you can fix with that book.
Download free RTA application for iPhone, run pink noise from speakers, and see what you get at listening position. Then repeat with each channel individually. This is very crude, but also very helpful. Something in your playback change probably has "balance". You can adjust this if you cannot rearrange your room to be more symmetric in response.
Based on this post and my difficulties with my room I had tried everything I could think of, until I tried the Sumiko Master Set method. Its the only one that worked. Everything snapped into focus. The images float in the air. I can't hear one speaker over the other no matter where I sit. The midrange is natural and lifelike. The bass is even and full without exaggeration. It took about 2 hours but finally I can rest easy. No bull. It works. I have an odd room with a ceiling that is lower on one side and asymmetrical furniture. It doesn't matter. You are tuning the speakers to the room. No formulas. Similar to Jim Smith but infinitely easier.
great news T,
where did you find the details on how to do this method? I googled and Binged with no result. My room blows as well but I think I have it sounding pretty good but..........
There are several post on Audiocircle. I'm not home now. Try "Sumiko master set speaker placement" and look for the audiocircle posts. Email me if you don't locate it and I'll send you a link. Good luck!
Paulsax, I copied the instructions from one of the Audio Circle posts. Send me an email and I will send you a copy.
Talk with Bobby at Merlin to get his view as well.
thank you all for your advices!
the main problem with my system was probably beyond what a bad room acoustics can cause. some time after I bought the VAC super I changed and altered some of the tubes and stayed with it.
well, I now put back my original VAC tubes (4 KT88, 5 12AU7, 1 12AX7) and I put them in their RIGHT order after consulting VAC. each KT88 I put in its right socket number (I had never notice the socket number is written on the tubes) and the two golden dragon 12AU7 had to be in the edges and not anywhere else.
the sound now become so better as it should be from a hi-end system! yes, still there are some problems with room acoustics and I am going to try and fix it but the sound is so good and balanced now...
just before I found my problem I ordered the filarmonia amp from ars-sonum spain. merlin and some reviews claims its a very good match with the merlins so maybe after I get it the sound will be more better...
anyone can explain why the KT88 tube where numbered to their sockets ? is it because tubes "matching" ?
A WAG. Not enuf info to tell for sure, but my guess is that the tubes were biased by VAC when they had possession of the amp and the tubes were in the correspondingly numbered sockets. ARC always does this for example when the amp is sold new or it is returned to them for tube replacement.