Unbalanced sound stage

[Castalia]

Hi,

I'm having a problem with my speaker setup which really annoys me.
A couple of moths ago I finished my new OBs (2 x Eminence Alpha 15 + Fostex FE168EZ).
First impression was quite good, however, I noticed that the voices didn't come from the center but from the right channel. Just as if the soundstage is 'panned' towards the right channel.
I'm sitting exactly in the middle between the two speakers. I expected to hear the singers in front of me, but it's just like they keep standing in the right corner of the stage.

Of course I started experimenting. I swapped driver polarity, changed my cd player, tried other amplifiers, other cables, swapped the left speaker for the right, and I adjusted some settings on my Behringer DCX (gain, delay, polarity...).
The only noticeable improvement came from a polarity switch at the right channel high pass. The soundstage improved but still leans towards the right.

My small room isn't optimal, in fact it's not appropriate for those large open baffles at all. And worst of all it lacks symmetry. But I'm very happy with the bass response, which doesn't suffer from the problem I just described; it only involves the high pass drivers.
Room dimensions are WxHxD = 4.0 m x 2.2 m x 5.0 m = 13.1 ft x 7.2 ft x 16.4 ft
Distance between OB's (driver center -> driver center) = 1.65 m = 5.41 ft.
That's also the distance from the listening position to the drivers (~ equilateral triangle). I tried different positions but the problem remains. Pretty frustrating...

Any help would be really appreciated. I can provide pictures if you need. Thanks in advance.

Erwin.

[Pano]

It does sound like you've done all the basic checks. Nice trouble shooting!

Have you double checked polarity of the drivers and the signal going to them? Maybe a miswired driver, or one of the cables coming out of the DCX.

If all checks out and you think it's the room, maybe you could shift the delay a bit witht he DCX. Delay the right side and/or drop it in level a bit. It can work well.

[KSTR]

At first you'd need to really double check that the speakers (+XO+amps+source) are playing identically. I'd move them close together (as close as possible) and then play mono pink noise and listen if all is well centered/balanced.

Then the next step would be to to find the acoustic center in your planned listening area and speaker setup. I like to use a mono sine sweep up to 1.5kzu for that. Readjust listening pos (and speaker pos also, trying to keep symmetrical distances from all walls) until this sweep stays in the center as much as possible for all frequencies (don't give up too early with this, but it will be hard). Then "phase" the speakers, that is adjust the minute distance mismatches to the listening pos until the pink noise stays centered (better said: stable in localisation and coloration shift when moving your head slightly), also trying to optimize to the best toe-in (reached when lateral sweet-spot width gets largest). Part of that could be dealt with global channel delay also, but I would try to not use that if possible. Same with EQing (that can be done to fine tune things once the basic geometric setting is right). Finally you can apply subtle channel balance level changes to readjust the percieved center (but time/phase is a bit more important than level). All in all a very iterative process, may take a few days... and photos of your room and a decent floor plan especially would help for further remote analysis.

- Klaus

[norman bates]

could be many things.

could be the right side of your room is more reflective.



norman

[Pano]

That's what I was thinkin' (mine is)

[hm]

Hello,

years ago someone show me a foto
of his room with two Manger 3head speaker
left and right book shelfs, but at the right there was
a part of 40x40 cm glas.
i ask him dont you think sometimes is the voice
soundstage at the right dominant?
Yes.
removed the glas it never happens again.

Set up is important,
but you did all,
except, make a single nearfield measurement
of the driver also from rear, may be the driver
are not so equal as it should.

[Castalia]

Thank you for responding.

Originally posted by panomaniac

Have you double checked polarity of the drivers and the signal going to them? Maybe a miswired driver, or one of the cables coming out of the DCX.

If all checks out and you think it's the room, maybe you could shift the delay a bit witht he DCX. Delay the right side and/or drop it in level a bit. It can work well.

To be 100% sure I rewired everything this morning. I tested the driver's polarity by wiring them to a battery. All drivers moved frontwards, so they're wired correctly. Listening confirmed my previous results, the voices are still coming from the right.
Then I swapped the left loudspeaker with the right. No improvement.
At this point, the amp's left channel had been connect to the left side, same for right. So I changed this too, to be sure that both amplifier channels are equal - they are.
Changing the wiring at the DCX didn't improve anything either.

I tried your suggestion regarding delaying the right channel. The soundstage balance gets better when the right input channel is being delayed (distance = 0.25 m, time = 0.73 mSec), however, the sound becomes somewhat 'blurred'. Not much though, so it could be good as a last resort.

Originally posted by norman bates
could be many things.

could be the right side of your room is more reflective.



norman

That could be very likely. Are there any workarounds for this issue?
The speakers seem to be OK, just like the amps, cd-player and DCX...

Originally posted by hm
Hello,
Set up is important,
but you did all,
except, make a single nearfield measurement
of the driver also from rear, may be the driver
are not so equal as it should.

When I measured the Fostex drivers I was a bit worried at first; There was quite some difference between the two drivers (Qes 0.40 vs 0.30, Vas 15.3 vs 20.6 L), more than a common 10 - 15%. But I don't think that's the cause of the problem.

Thanks again.

[mjf]

hello.
did you check your audiocable,speakercable?
you can swap them..............or measure it with a simple dmm (ohmmeter).
or you can use another amp or speakers and hear what happens.....................
greetings...........

[StigErik]

Try to run a mono signal to both your speakers by connecting both speakers to either left of right channel output of the power amps. All sound should now be located in the center between the speakers.

If you still have the image problem, its most likely related to your room acoustics: early reflections.

[Castalia]

These are pictures of my room. As you see, the right loudspeaker has a little bit more space than the left speaker. Also, the door at the left could have some influence, just like the wardrobe between the speakers.