don't run your LD's horizontal. some weird phase issues can occur. they were designed to be run vertical. i've done some tests and sure enough, it sounds better vertical.
WHAT!!!! enlighten me...how can this be circularly affected? Is this some info from the manufacture or tapers wives tales ;-)...seriously though, I don't think it matters if the mic is on its side or not...the faceing of the diaphram is the front with the center being the center of the pattern that is a 3d image going around it from front to back ...w/ the patteren rolling off as designed...encompasing your face from nose out past the ears to the back of the head......IYKWIM
have you really experienced some weir phasing due to laying the mic on its side (w/ the xlr out to the side)...how do it know if it is upside down or sideways or "correct"?
I don't think it does, Prolly just some other reason for whatever you heard or heard of.
rock on you big diaphram guy you
jah
ps to get better sound on LD's.....go up front.
peace
jah