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Stereo image abnormalities

H

HowardMil

New Member
Hi:
I’ve been trying for weeks to get a grip on my new room and how the stereo phantom center keeps shifting slightly to the left.
The room is 14 by 24 by 8. Drywall.
For imperative purposes , the loudspeakers are on the 14 foot wall ( which is good!) firing downward.

Speakers 3.5 from sidewalls to the mm—- 4 feet from backwall to mm.— 8 feet apart and toed in 22 degrees. I sit 11 feet from speakers baffles.

However: the first 4 feet of the left wall adjoining the 14’ wall has a small indentation (alcove) of 8 feet high, 4 feet wide and 10 inches deep.
The left and right speaker cabinets are 4 feet out from back wall— ( here the small left side asymmetrical problem exists.

Also - right side wall has a 6 by 3 foot window ( half covered by absorption blanket and sits behind my right GIK first reflection panel which is 48 by 24 inches.
I have similar GIK absorption panel on left side ( straight drywall).
I have 2 GIK monster bass traps on ceiling corners behind speakers. They have range limiters ( why GIK advised this , not sure. Floor is fully carpeted.
I’m trying to figure where the imbalance is generating from.

I’ve covered alcove on left with full absorption blanket and half window on right behind first reflection point GIK panel. I’ve put absorption on right side of right speaker drywall- then took it down. Now it’s covering the LEFT tiny alcove next to left speaker.

I was told on another site that there is really one main solution (??) ( the right window is not a main problem-??) : Fill up the tiny left side alcove area with drywall and it’s all then “SYMMETRICAL “ .

I’ve switched speakers sides, amp cable channels, different amp, cable switch from right to left..etc.
Any help or ideas appreciated
Thanks
Howard
Pictures can be posted if needed.
 

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Yes, there are times if my head moves to left or right ,,it centers good, but the end of the program tracks always seem to ' fade' or finish with the sound diminishing to quiet towards left speaker.....i will upload pic in a few minutes
 
Serious question, does one ear "hear" better than the other?
Pretty sure I have more hearing loss in my left ear as I have to compensate with left channel adjustments.
In addition, at the end of any song, sounds always fades out last in the right speaker.
 
mmm interesting question. might... have minuscule high frequency loss in right ear.. ; nothing out of ordinary for my age 65
I feel certain however, that that tiny left side alcove has something to do with it
 
Your room is an echo chamber with a port to the left. Hard floors, hard walls and a hard ceiling all add to extreme first reflection bounce. Your brain tries to center the stage, but soon tires of the lopsidedness from the rooms boundaries and surfaces. You need to start adding some "clutter" to tame the room. The room is the 2nd cabinet to the speaker, if you will and if you do not treat it like the interior of your speakers, bad things happen.

In the mean time, you might roll up some old bath towels and hang them in some first reflection locations near the outside walls. These towels will help absorb some of the rebounded stuff and should help to redefine the stereo image and keep it from drifting.
 
I had a similar problem a few weeks ago. My apartment living room has simulated hard wood floors and bare walls on 3 sides. At times, every reverberate at high volume. The stereo image was shifted to right on every source despite the speakers being equal distance from both rear and side walls. Then I played a mono source through the speakers, the image, which should had been centered between the speakers, was shifted right. I found my problem-just reverse the speaker cable leads on one speaker. Image shifted back to center. As for the room, I got an area rug and some curtains which has tamed some of the reflections.
 
Looks like you have a nice listening room and system.

For starters, a couple of things to think about.

For one, rooms are basically never perfectly square. So I always measure speaker distance and positioning from the listening position, rather than from the walls. I use a tripod and a laser distance finder (mounted like a camera where the center of my head would be, swiveling left and right) aimed at the center of the tweeters. This can also be used to verify identical toe-in angles, by aiming at the top corners of each speaker.

Have you tried listening from a closer position? This might help determine where in the room the imbalance is coming from.

Also, can you correct the problem by adjusting the angle of one of the speakers? This also might help pinpoint where the problem(s) are.

I would also center the gear rack, even though it probably isn't a big factor.
 
Good answers , except first: not an echo chamber; carpeted throughout- first reflection points covered ( panels) bass trap on ceiling ( still don’t know why gik advises limiters instead of full range absorption) and not in the picture- back wall has 3 diffusers 24 by 48

Now — Mkane says STUFF alcove : wit what? Wish I could buy a permade drywall panel! I have measured speakers to the mm —for toe in and length from all walls. One thing: my measurements from left wall to speaker is (naturally ??) from the wall without the Alcove...

Get this: Dennis Foley just said make walls on left just like wall on right— but I have a window on right— should blinds be absorption; reflection ( drywall amount) or NEUTRAL?? He then said cover 3..... sidewall reflection points.. ( WHAT is the 3rd?? )
Then when he saw I had no money for HIS products ( having spent approximately $1500 on GIK products) he cut me off - giving me half time of our allotment of 30 minutes!!!!

Any more ideas are truly welcomed
 
I had this exact problem but solved it by bringing the speakers away from the wall. Three feet if possible. And move everything away from them. Worked wonders for my system.
 
Thats what happens when you use point source speakers in a non symmetrical hard room. There are just to many room modes to un-stabilize your speakers emissions.
 
First, I would check with headphones to ensure all your gear is working properly for the preamp Output. It probably is okay, but if you do note the same anomaly via headphones, then you need to look at preamp or source.

Second, temporarily swap L/R channels to see whether the fade changes to the other side. If it doesn't change, then it is likely the room, but...

Third, with L/R back to normal, physically swap the speakers, then listen again to see whether the problem changes. If it remains as before, it is almost certainly the room; if it changes sides, then you may have a speaker issue - several times I've rectified such things with a simple recap, though driver or other issues are possible.

Which brings you to where you are now, with room anomalies to address, but, hopefully you already checked the possibilities above.
 
musichal said:
First, I would check with headphones to ensure all your gear is working properly for the preamp Output. It probably is okay, but if you do note the same anomaly via headphones, then you need to look at preamp or source.

Second, temporarily swap L/R channels to see whether the fade changes to the other side. If it doesn't change, then it is likely the room, but...

Third, with L/R back to normal, physically swap the speakers, then listen again to see whether the problem changes. If it remains as before, it is almost certainly the room; if it changes sides, then you may have a speaker issue - several times I've rectified such things with a simple recap, though driver or other issues are possible.

Which brings you to where you are now, with room anomalies to address, but, hopefully you already checked the possibilities above.
Click to expand...
I think OP said that he did all of these things already with swapping things around.
 
HowardMil said:
Yes, there are times if my head moves to left or right ,,it centers good, but the end of the program tracks always seem to ' fade' or finish with the sound diminishing to quiet towards left speaker.....i will upload pic in a few minutes
Click to expand...

Are you willing to move your listening chair to the right?

Symmetry of your speakers and chair is a good starting point,but once you get the the placement optimized for the bass and treble, you may have to tweak things to lock down the imaging.

Also, I've heard a lot of music that fades to left or right at the end of the track, so a mono record would be best for lining up the center image.
 
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