The T1 gen3 is an entirety different headphone, and a far departure from what Beyedynamic normally has made. It is meant to be easy to drive and can run of a iPhone, but is has very muddy in the bass, mids are warm, and highs are less peaky...
They tried to make it more "main stream" and failed. Beye has had more or less had the same soundsigniture from 1983... With only the X line and T1/T3 gen3 taking a departure from it. ( Talking about over ear here )
The DT1990 is a TOTL studio headphone.
I say it again TOTL
STUDIO HEADPHONE.
It's a workhorse. It's ment to find flaws in recordings.
That is what makes it great, and what also is it's downfall. The hyper detail also require clean recordings. If you have that, then it rocks.
Ps. Before someone says " it's fake detail"... Just remember you can't hear something that's not there on the recording in the first place.
PPS. - I love it for listening to live symphonic heavy metal