Sorry, I meant the DT 880's. I own the 990's, they do have ample bass for sure. Beyer claims the T1's are highly efficient (sensitivity). I believe spec is 102db which is high for Beyers relative to their popular Hi-Z phones which I think they spec around 96db. Just wondering if you find that to be pretty accurate, especially seeing how you are familiar with Beyers. The Crack drives the 990's easily as well.