Soundstage Puzzle!

[MadFloyd]

I am wondering if anyone can guess what is causing my center image to shift to the left. This has been plaguing me for quite some time and I've ignored it (mostly out of laziness) because when I play LPs the image is well centered (which is only because my azimuth is a little off - conveniently in the right direction).

I use laser measurements to ensure that the distance to both speakers is the same. The interesting thing is this: if I pull the speakers out a few inches (i.e. closer to the listening position) the image centers. So it's some sort of room interaction that is causing the left channel to be louder than the right. Unfortunately the speakers perform better where I have them now so pulling them forward is not my desired solution.

I have added a bunch of absorption panels on all walls that appear like they might be coming into play without solving the issue.

My room is not typical (you can see photos and a diagram here).

All guesses count. Thanks for playing.

 

[Steve Williams]

possibly related to one wall being open to the kitchen

 

[MadFloyd]

possibly related to one wall being open to the kitchen

No doubt. But why does 2 inches change it? And why wouldn't the right channel be the louder in that case?

 

[Steve Williams]

in situations like this, I find a L-R balance control on the preamp works wonders

 

[MadFloyd]

True. Somehow my brain tells me that I am cheating.

 

[Steve Williams]

I had the same problem in one of my former rooms that was somewhat uneven or open. I tried a lot of things until finally I used the balance control on my preamp.

 

[Frank750]

I have an open doorway almost dead center in my room on the left side and I have to swing the balance to the left to compensate. Always have, no matter what speakers or electronics I have in the room. Thought about closing in the opening but it doesn't bother me any longer.

 

[jeromelang]

It's a static issue.

Search for answers in one of the posts I made recently.

 

[dallasjustice]

There's no need to guess. Do a sweep of r and l. Then overlay them in the ETC tab in REW. You'll see the differences in early reflections. You can easily identify which reflections are the cause. The ETC will tell you time delay for the reflection. You then just convert to distance and subtract from the direct distance. That number will be the distance from the listening position to the offending boundary.

Or you could continue guessing. . .

Eg. Maybe it's your amps. Try pushing one back 2'.

 

[Steve Williams]

There's no need to guess. Do a sweep of r and l. Then overlay them in the ETC tab in REW. You'll see the differences in early reflections. You can easily identify which reflections are the cause. The ETC will tell you time delay for the reflection. You then just convert to distance and subtract from the direct distance. That number will be the distance from the listening position to the offending boundary.

Or you could continue guessing. . .

Eg. Maybe it's your amps. Try pushing one back 2'.

Michael

your first comment was informative. Your second was unnecessary IMO

 

[dan31]

Try more toe in on the left speaker or less toe in on the right speaker. This may help. Alternately you could move the left speaker closer to the listening position. As noted this is what the balance control is used for. Remember your room is asymmetrical so your speakers position should be adjusted or just use the balance control.

 

[Al M.]

True. Somehow my brain tells me that I am cheating.

I don't think you are, you are just correcting for a room anomaly. I also use laser measurements but I have to pull the left speaker closer about 1 inch for a centered image. In your case try pulling the right speaker closer.

It's nothing abnormal, really. The trick of pulling forward one speaker a bit for centered image is even described in the official manual of setting up Genesis speakers (I got it from there BTW).

 

[PeterA]

Here is another thought, Ian. Think of your speakers as being located on the periphery of a circle with the listening seat at its center. You have written that you use a laser to confirm that speaker distance and toe in to the listener (center) is equal. Now try moving one or both speakers along that circumference always maintaining the same distance and toe in (and tilt) to the listener until you get hear a stable, focused center image.

Given that your room is highly asymmetrical, you may also want to slightly adjust your listening seat thus establishing a new center of the circle and start the experimenting again. This will be a time consuming and frustrating exercise, but it might help.

I like Michael's suggestion about taking the measurements and analyzing the results and then using room treatment at the reflection points. That should work also, but would require the measuring gear and knowledge about how to proceed. I have neither the gear nor the knowledge to attempt this solution. I would also not resort to using the balance knob as a simple and easy fix. That might effect the sound off axis and alter the size of the sweet spot, but it might provide a simple but not ideal solution.

I would also attempt to find a solution by listening only to digital, and not analog, as it will provide a stable source.

Laziness is not your friend in this case. This is a fun game that you have invited us to play.

 

[Mike Lavigne]

I think it is possible that this is a signal path issue, and not acoustical. you did not say that you have checked that......and if you did and I missed it sorry. typically any problem has the most obvious solution but sometimes we assume that cannot be it.

of course, I mention this because I've had 2 personal experiences with this exact issue where it was signal path. once it was an impedence switch on my amps where right and left were different. a second time my phono stage had different value gain setting for left and right. in both cases I lived with it for awhile and was lazy getting around to diagnosing. also; I had one tube going off on one side of my Golden Gate and until it got bad enough to get really low I was wondering what was happening.

simple to check......start at the speaker end and go backwards. use a mono recording where you have a known dead center vocal or use the mono switch on your preamp.

first switch speaker cables, then pre to amp interconnects and then source to pre interconnects.....and check any gain related settings like impedence or phono gain.

likely you have done these things but just wanted to mention it.

 

[fas42]

My take on this is that one channel is effectively "better" for some reason - it's the channel that's "worse" that the sound is drawn towards, subjectively. So the solution is to balance the perceived quality between the two, and adjusting at least one of the speaker positions is certainly one approach for doing this. My technique would be to try to determine what is intrinsically causing the quality deficit, and correct that - a friend with vinyl had the sound pull to the right, which corresponds to what was said in the OP; but we didn't touch the speakers, the issue was the tracking of the cartridge and we spent ages tweaking the alignment there, to get the best possible quality right at the source - the smartest solution.

 

[PeterA]

I think it is possible that this is a signal path issue, and not acoustical. you did not say that you have checked that......and if you did and I missed it sorry. typically any problem has the most obvious solution but sometimes we assume that cannot be it.

of course, I mention this because I've had 2 personal experiences with this exact issue where it was signal path. once it was an impedence switch on my amps where right and left were different. a second time my phono stage had different value gain setting for left and right. in both cases I lived with it for awhile and was lazy getting around to diagnosing. also; I had one tube going off on one side of my Golden Gate and until it got bad enough to get really low I was wondering what was happening.

simple to check......start at the speaker end and go backwards. use a mono recording where you have a known dead center vocal or use the mono switch on your preamp.

first switch speaker cables, then pre to amp interconnects and then source to pre interconnects.....and check any gain related settings like impedence or phono gain.

likely you have done these things but just wanted to mention it.

Would this problem show up when Ian listen to both analog and digital? I suppose it could be signal related with only his digital, that is before it hits the preamp.

 

[Mike Lavigne]

Would this problem show up when Ian listen to both analog and digital? I suppose it could be signal related with only his digital, that is before it hits the preamp.

he needs to approach it objectively.

I agree that it seems inconsistent with a signal path cause based on that comment, but my point is simply make sure you know what is not causing the problem. trying to find an acoustical solution can be a lifetime endeavor. it's just so easy to test the signal path you have to do it first. first things first.

 

[Steve Williams]

It's interesting to hear all the suggestions as well as the suspected causes. I wasn't being flippant before but having had this problem and knew it was an issue similar to Ian's I said that is what a balance switch will do or to use different gain settings for each channel if you have mono amps

 

[DaveyF]

Madfloyd, I have looked at your room before and it's a tough one! Essentially your room is an alcove off the kitchen! Getting great sound in that space is clearly no easy feat.
Here's a thought.... next upgrade is a new room. Probably the best upgrade you could make. Unfortunately, also the most expensive. When one lives in a pricey Real Estate area, the most expensive component ( usually by a country mile) is the room.
I really suspect that many members here have no true concept of the cost of some of this real estate in areas like California, Boston, New York and the like.

 

[Barry]

Steve answered the question and yes it will be for every source.

The imaging problem isn't the direct sound since the speakers are exactly the same distance to your listening position. It's the reflected sound. There is more reinforcement from the walls near the right speaker that push what should be a central image to the left. To offset that you can change the preamp balance favoring the left channel or move the left speaker forward, as you have done, and it will sound better, but the image balance will still be slightly off. Any asymmetrical toe-in vis-a-vis the listening position will likely mess the soundstage up more. Don't do that.

You might consider hanging something above the half wall in the kitchen seating area to partially fill in the open space. Perhaps, a 4' x 4' framed stained glass art work that matches the decor and maintains the open feeling of the house but provides enough reflective surface to restore the balance? You shouldn't have to build a new room!

Oh, I've had this problem too so I know what you're dealing with. good luck!