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
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