I don't know if this helps, but since it is working perfectly here I thought I could share what I did.
Without delay, I always heard the left channel louder and "closer" to me, so that the supposedly "centered" singer's voice would sund slightly on my left, and the whole stereo image was distorted towards my left.
SO, I started to delay the left channel (acoustically pushing it away from my position by the amt of cm. indicated on the display) until I clearly heard the singer's voice right in front of me (I did not measure anything, I just closed my eyes to figure out it all better). When I reached this status I could hear the whole stereo image much more clearly. Everything sounds better now, noticeably!