I recently had the dt 1990, and after having them for around 3 weeks I was able to determine their strengths and to who exactly they were targeted for. I’ll keep it short and simple while making comparisons to the largely revered Sennheiser hd 600.

Build- Simply amazing. From the earpads, to the box, to the cups, this headphone was built to last. The pad change was a bit frustrating but is a small price to pay for the build quality one receives. Clamp force may not be suitable for unusually large heads.
Targeted Audience- professionals, people who want to mix with them. Definitely NOT for the casual afternoon listener wanting to relax.

Bass- The semi closed nature helps create a nice bass thump. Slightly less punchy than the hd 600, but with significantly more impact and presence.
Mids- a slight downgrade from my hd 600. The dt 1990 do not have the smoother more pleasant mids of the hd 600. Instead they are a bit further out of the headphone and into the cups.
Highs- Here lies the controversy. If anyone complains about “treble veil” from hd 600, they should definitely move to these. Highs are significantly more present, and brighter. I’d argue just slightly too bright and peaky in certain parts. This aspect was definitely made for pros in mind who want to hear the sibilance and highs.
Overall, an excellent offering by beyerdynamic. But I’ll state it again, this is a headphone you concentrate with not a headphone to relax with at the fire place.