centering the human voice

Can we assume the voices you are trying to center are recorded that way?

You should be able to locate a voice in the soundstage with certain quality recordings but no guarantee voices are always mixed in so as to occur in the center.

Your room may well be a factor in an unbalanced soundstage left to right but I think that would probably affect more recording elements and not be isolated to voices only.

How far are the speakers from the side walls. What sort of surfaces are on the side walls? How far do you sit from the speakers?

Can you try the speakers along a different wall, even temporarily just to hear the effect?

Don't be afraid to sit a bit off axis if the soundstage sounds more balanced there.

I really don't think there should be this much of a problem unless one speaker is _very_ close to some very reflective surface (something like tile or glass). Our ears are actually pretty good at sorting out reflected sounds from direct sounds (Floyd Toole's book has a lot of info on this).

In the end, if you can't get stable imaging by moving the speakers around, trust your ears and contact your dealer about a possible problem with the speakers.

I think mapman has a valid point. I also find vocals on a number of recordings to be off to the right or left a bit, and I also get perfectly centered vocals, which makes me believe that this is just the nature of the recording. As he mentioned, the rest of the soundstage should shift also if it is a speaker placement/room issue.

Hummm, maybe we should start at the beginning. Are your speakers wired correctly in-phase? Be sure BOTH speakers are wired + to + and - to - or red to red, black to black. If they are out of phase you will never get a consistent center image.

If they are properly in phase, swap the speak wires at the amp end, left speaker to right output and vice versa. If the image stays offset to the same side as before, the problem is likely room acoustics or the speaker. If the image moves toward the other side, the problem is somewhere in the electronics or wiring of the system. Or, it could be a recording that simply places the vocals off center as suggested above.

Can't hurt to verify these simple, but often missed, steps......

Enjoy,

TIC

Ruebent makes a good point and the tests are well worth doing first and foremost to isolate the problem. If the problem is not with the electronics/wiring you may then want to go and get one of the many test CDs out there that include voice and imaging test tracks. Two that come to mind are Stereophile Test CD #2 and the Chesky Jazz Sampler. Play the test tracks and note the results.

Follow that up with some reading on speaker set-up and room treatments. One thing that I have learned is that speakers do not have to be placed symmetrically in a room to sound right. Take a look at the Sumiko Master Set and Audio Physics speaker set-up methods and you will see examples of this.