Listen to tracks like Bob Baldwin's Everybody's Beautiful or Till Brönner's Track One and you'll hear that deep sub-bass. I also think these have significantly heavier bass than most headphones I've heard in this price range. Wouldn't say it's awfully well controlled and indeed there are some resonances to be found. But it's not bloated or boomy and doesn't drown out the mids. They are a little bass-boosted but hey they do it in a good way. They are fun sounding hi-fi headphones, who value punch and slam rather than neutrality and naturalism. I will say though, they do manage to get a lot of detail in the music, so they're very clear sounding.
Tried them with my speaker amp, playing the Blu ray of Avengers. The deeper bass notes really surprised me. You really felt the force and vibrations of the low notes inside the cups. Wouldn't say they lack sub-bass or punch at all. But hey, thats just me