I think that the paradox that some people miss, is that you feel more the bass of hd800,
when the treble is tamed. So obviously some source are taming more treble than other,
but I don't think that strictly speaking that sources that tame treble can be called "transparent" .
Regarding the bass impact, the hd800 definitely can be quite "showy" and interesting .
I was impressed while listening for instance to claude von stroke , chimps ;
but taming treble with an eq helps.
And regarding "visceral bass", I have in mind this, and the intended ambiance fail
a bit on the hd800: