I have read of the claim in subjective reviews of speakers. I had always thought it a myth. I have heard it myself. AHHH! WHERE IS MY MIND?.
Two choices really: 1) enjoy your new system, or 2) you are experiencing the duplicity of stereophony, immediately disconnect one of your speakers, switch your amp to mono and move the remaining speaker to the centre (sitting yourself on a wooden stool will help restore austerity).
Joking aside, as tomtoo and dasdoing's links above attest, it's in the mix. Contrary to widespread misconception, the first choice is the red pill, the second is the blue, not the other way around (at least as far as intended reproduction of the recording is concerned). I get it on much of the stuff I enjoy. You probably didn't hear it before because your (previous) system wasn't as good.