Imo neither is correct as there is no absolute opinion and everybody's perception of sound is different. If someone says that the LCD-X doesn't sound relaxed, it is his/her perception. Only because others may disagree doesn't mean that it isn't true for that person. As ear anatomy, hair, HRTF, mood, personal tastes and preferences play an important role a single headphone won't sound identical for everyone.
At least I can say that (compared to the neutral Etymotic ER-4S and almost neutral UERM) to me the HD 800 has a moderately recessed midrange, as well as moderately emphasised highs and a hump in the bass region, whereas the LCD-X has got the more full-bodied sound signature with evenly emhasised bass and ground tone, prominent midrange which is rather on the dark side, as well as a recessed presence area. That's what I perceive.
At least I can say that (compared to the neutral Etymotic ER-4S and almost neutral UERM) to me the HD 800 has a moderately recessed midrange, as well as moderately emphasised highs and a hump in the bass region, whereas the LCD-X has got the more full-bodied sound signature with evenly emhasised bass and ground tone, prominent midrange which is rather on the dark side, as well as a recessed presence area. That's what I perceive.