That's going to be an interesting test.
Best bass - impact and details? Let me listen for a couple of days and I'll get back to you.
It's the T1.2 not the T1.1. The later version has boosted bass.
I was actually enjoying the HD800 with LF339 for it's intoxicating details until you pose this question. So now we have to consider bass. That means HD800 is definitely off the radar. My first thought would be:-
1. LCD-3f
2. T1.2
3. Verite
Now as I compensate the volume for each headphone, I'm not so sure.
T1.2 certainly have the high frequencies dial back compared to the other 2, so you'll loose a bit of details compared to the other 2 but the bass is lower.
That said all 3 headphones are certainly enjoyable with Yggdrasil > La Figaro 339. Very different presentation though.