centering the human voice


i cannot center the human voice coming out from my jmlab
electra 926 ??
they are placed in an irregular room with openings
i do not know how to place speakers!!!!
they are 5 foot from the front wall and about 6 foot apart
they were ok but the soundstage seems to shift to the left
despite i try different placements by trial and error
jmlab926
What's different about the new speaker placement compared to the way there were positioned when you could not get a center image?
the new placement is used for my 2nd pair of speakers
the original one was for the jmlab which were placed
on an area rug
i finally measure and readjust to get the center point
the radio's center point is more consistent than that of cd recordings