Happy new year! Just got back from a new year party. :)
I think "lifeless", at least for me, is a relative term. The term has to be put in context and described in relation to other known HPs. In my case, it's the HE500. For other people, it could be T1 and maybe different top end HPs. Taken out of this context, the terms "lifeless", "cold", "analytical" will not make much sense. Also, it will totally depend on personal preference. Some of us might prefer HD800 exactly the way it sounds and there's no need to warm/lush it up in anyway. Some of us will change every single component in the chain to somewhat alter HD800 to his/her liking. For me, I bought the HD800 already knowing/accepting the way it would sound with my current chain. I bought it to complement what I already have (HE500), not to have another HP just like the HE500.
Sure, context is very important. I have a proposition for comparing the euphony of the HD800 to other headphones. So let's use a percentile system, comparing to all other respectable headphones, from mid-fi to summit-fi. So anything from M50 and onwards. No consumer headphones. Assume each headphone is being put through a system where no sound signature of the chain is added, so we're just comparing stock sound of the headphones here. Also assume every headphone is properly driven with the appropriate power requirements. Now that we've establish a large set of respectable headphones and parameters, let's try to get a percentile number on euphony and musicality for the stock sound of the HD800. Would you consider it top half or bottom half? The way it has been described, I get the idea it's bottom 10%ile on this rating system. Now if you were allowed to add a chain that brings out the most musicality out of the HD800, and let's keep all other headphones with their stock sound, so they don't get the benefit of a chain optimized for euphony. So what percentile is the HD800 on that scale now? Does the HD800 have the technical feasibility to break into the top 25%ile even with the most ideal setup for euphony, and still comparing to other headphones with their stock sound? Even if one optimizes the HD800 for musicality and euphony, could it be on par to headphones that have a general consensus of being euphonic at their stock sound?