You should not have to tow the speakers in towards the primary listening position as they will generate a decent soundstage positioned straight. How far a part are they from one another? Also, how have you calibrated the Receiver? You want to leave any tone/treble controls at zero. I can't remember if that model of the Pioneer has the mic setup, if so it is ok to use that to help setup speaker levels and distances, but turn off any Room EQ, if that model even has it. On my Denon, I found the Room EQ made the m60's sound like there was to much midrange. Another thing that seems silly, but many have made this mistake is how you have the speakers wired. Obviously you want to retain the proper polarity, but you didn't remove the mounting clip between the terminals?
My guess is that it has to do with receiver calibration
