I always felt that both the T1.1 and T1.2's bass was slightly under what I would like (like other Germanic TOTL headphones, say like the HD800/800S or HEDDphones). After having the T1.3 since this weekend for an upcoming review, I can now say that they hit the nail on the head. Real life has bass, and why shouldn't your audio gear reflect this? No it's not TH-900 or Z1R overly inflated bass, but it is at a far more natural and enjoyable level to my ears. They are slightly warmer overall too, but I would have expected this warmth would take away from their sense of air and space as it has typically in the past with other headphones. Surprisingly, beyerdyanamics improved that too! Their ability to cast both a wide and deep sound stage is very impressive!
I can now use them on systems that aren't part of my main rig. The 32 ohm impedance and corresponding efficiency has them sounding great out of my FiiO M11 Pro or pretty much any other portable unit I've thrown at them (including my iPhone). That said, things to kick up several notches when I plug them into my Chord Hugo 2 or DAVE.
More to come...but it's gonna be really hard to send these back!