Need help with room problems


My specific issue is that my "sweet spot" is very small and quite dramatic. My "system" link will show you some visual details but here's more info.

My room is about 16'x 12'x 8'(height). System is on the long wall. Speakers about 23" from rear wall, 6'3" apart and my head about 8' from them. No toe-in as recommended by the manufacturer. Room is flanked on the left by a large window starting 3' from the floor and is centered measuring 4'h x 7'w. It is covered with curtains, though not heavy ones. The right is open to the dining area, and a half wall that leads into a hallway. Two large bookcases are at the first reflection point to try and minimize the chaos of the hallway.

If I move my head more than about 6" the placement of the instruments change quite drastically. The effect seems to be with the right speaker. Sometimes the sound is as if from the speaker and in the sweet spot, the speaker "disappears".

I looking for suggestions as to what to do to deal with these problems.

Thinking of trying the system on the short wall with the window behind it but I am concerned about the bass response due to the ports. Also wondering if the open dining area and the opening to the hallway will send the sound off into oblivion.

Thinking of diy roomlenses. It is the living room and unfortunately the only possible room. Also we rent so I can't alter anything but the furniture.

Thanks.
stuartbranson
Actually if I move my head to the right there is a very discernible line across which the balance shifts quite dramatically.
One of the downsides to highly resolving cone speaker systems is that they will give you a very narrow sweet spot. It is normal for the center of your soundstage to shift to the left (for example) if your move your head to the left. Speakers that provide you with a wide listening area usually do not provide sharp resolution/focus. But there are a few things you can try, one of which sounds far more radical than it really is. The easy one is to spread your speakers further apart and create something closer to, but not exactly, a triangle. The next sounds radical, looks different but it can really work if you keep an open mind and play with it. Instead of facing your speakers straight ahead, which will place you on about a 60 to 65 degree angle from the center line of your speaker, cross each speaker well in front of you on a similar angle. The sound that will reach your chair will be on about the same angle from the speaker as it was before, you will have no sidewall 1st reflection points to confuse the sound, you will diffuse the reflections from the ceiling so that they affect the sound less, and you will gain center fill. Because you can locate the speakers very close to the side walls, this would work well for you on the short wall where you could set up a listening triangle of with speakers about 9 to 10 ft apart and the chair about 10 to 11 feet from the speaker. As a benefit you will also get a sense of sound stage when sitting directly in front of each speaker only it won't be highly resolved - good place for a second chair if you need one. I use this system in a slightly large room than yours with full range cone speakers - it took a bit to figure out the untimate placement (Inch at a time, week by week) but finally executed it really is excellent. Try it, its free!
Eenteresting, eenteresting. I can imagine it now. Not sure it would pass the WAF but it's worth a try. Never thought of it. Guess that means I'd have to change the left speaker for the right so the tweeters are properly aligned.

I know what you mean about the narrow sweet spot but right now it seems ridiculously narrow. I remember some bizarre post somewher in which the author suggested a kind of head vise to maintain objectivity during a review, (or something to that effect). Methinks I gots to get me one o' dem.
One of many reasons I like Maggie 1.6 speakers or anything above them (3.6's or 20's if you got the dough) are that they yield a very large 3D window on the music. The sweet spot is large if set up properly. And they do not sound much different even if you stand up.

But back to your problem. I can not know for sure but I can tell you that the largest improvement I have made in my system bar none, is the placement of 4 bass traps in my room. I can not tell you the difference in the size of the soundstage and how they helped eliminate smear. What I am suggesting is that maybe this is the reason you have such a small sweet spot????? OR at least it could be contibuting to it. Food for thought. But I also agree with the prior responses above that it has been my experience that many box speakers have small sweet spots. If you like box speakers, rather than planers, I heard some "Tyler Acoustics" that threw a very large presentation almost like the Magnaplaners.

Hope some of this was useful.

R.

Robert
Stuart:
I've checked your room pics. I second Newbee on trying toe in the speakers maybe not as radical but some you'll have to play with them as usual. Your room dimensions are close to mine and I ran into problems when I opened the speakers apart too much. Your idea of tweeter position inside or outside seems interesting to explore. I have noticed your bass trap type acc treatments. Do you have something for side wall reflections your "like corner" pic doesn't show clearly but there seems to be some furniture very close to the speaker, correct?
Do you have any acc treatment behind your seating position? WHat's your seat distance to back wall?
If cable length allows would really suggest you try to move back the rack and TV 2 ft behind speaker plane ....
Maybe you have tried before some of this ideas but would like to hear your comments
Regards
Luis
Your instincts are right. Try the short wall with the curtains behind your speakers. As an experiment, set it up without the TV between the speakers. Pull the speakers out from the wall about 3 feet and set them 8 feet apart on centers. Toe them in about 10 degrees. This will help to focus the soundstage and widen the sweet spot. Place your listening chair so your ears are about 10 feet away from the plane connecting the speakers. Make sure the symmetry is exact. Measure it carefully. Put the bookcases behind the listening chair. They will act as a partial room divider and also function as good diffusors. You could put some absorptive panels at the new first reflection points on the walls, but I would try it first without them.

This setup should give a large soundstage. Firing down the long dimension of the room is almost always preferable to firing down the short dimension. One advantage is it allows you to sit a little farther away from the speakers, which gives the sound from each driver time to integrate. The curtains behind the speakers are ideal for reducing reflections. This should be close to a LEDE (Live End, Dead End) approach which works very well. The open area behind the listening position will also help reduce reflections. Don't worry about losing the sound. The ideal case is for you to only hear the direct sound and the early reflections. Later reflections just serve to muddy up the sound.

If you must have the TV and equipment rack between the speakers, set them back at least 1 foot behind the front of the speakers.
Good ideas. In fact, great details. I think I will try the complete room re-arrangement and see how that goes.

At present the side wall reflection treatments aren't great, in the sense that the window on the left starts at the midpoint between the tweeter and woofer. There is a bookcase but a low one that is below the window. The right is open but I do have a large plush chair and some bookcases that correspond with the 1st reflection point. Maybe this deadening in opposition to the window's highly reflective properties is a problem. Other experiments with toe have been mixed. There is a focussing but a corresponding collapse of size and imaging. Hard to explain but the manufacturer suggests no toe-in and I have found that preferable in the long run. I guess I could put the TV on the other wall but I doubt it will reall work there. We'll see.

As far as behind my head. At present the wall is about 5", that is inches, not a typo, behind me with a large wool Iranian rug hanging the width of the couch. The speakers are about 8' away at the moment.

I'll try the re-arrangement and post again.
WOW!! It's completely different now!! I guess the equal sidewall reflections has cleaned up the sound. Also I am able to get a bit more room around the speakers and the bass is MUCH more defined and deeper. (strange but true). I didn't think my little speakers could reach down as far as they are. Also this new arrangement has cured a midbass peak I had been experiencing. The sweet spot is still narrow but nowhere near the constraints of before.

I don't know the exact measurements but I am a couple feet further back from the speakers and it's given me a much larger soundfield. I can turn it up a bit more now and get that bigger orchestral wash without feeling like I am in the first row. Depth of soundstage has increased.

Amazing, but just goes to show how the room is the most important component of all.

Thanks again for the prodding and the encouragement to do this.
Stuartbranson, glad your happy now. If I can make a suggestion, have you try swapping the speakers so that the tweeters are closer to the center then the outside. If so, how does it sound? Reason for asking is that I saw your system and it seem you have the tweeter on the outside.

Alfredo
Glad to hear it worked out. If you get a chance, could you update your pictures so we could see the results?
I have updated the photos! So glad I did this. The system has been so nearfield I am still getting used to the extra space.

Thanks all!
diy roomlenses won't solve the problem.

Get yourself a TacT Room Correction Preamp, it can deal
with level, phase and time delay issues of your room.
Stuart:
Great to see you have improved the sound drastically !!!!
Another plus for keeping in contact with our fellow Audiogoners