This ^^ .... Argyris described them exactly as I hear them - and they are still bright - even from my LD MKIV.
I still can't get over the fact that anyone could describe the DT880 as dark
@daleb - are you sure you don't have some sort of EQ/dsp working in the background? Turn any enhancements off (including EQ) then see if impressions change.
This is the bit that gets me ... apart from the mids being maybe very slightly recessed compared to the highs - they are pretty neutral. On the bright side (not dark) - but overall pretty neutral.