Just received a loan pair of Heavys, so I could measure the FR. These definitely have too much upper bass to produce clean sound, so maybe they pursued live gig style sound or something. I feel the bass is a bit too slow and it masks other frequencies. Even though the aggressive upper mids help to bring energy to the sound, for me they are almost too much. On the other hand, sound is loud and wild, which might suit the target audience.
Extra tweeters can be heard clearly, as treble cuts quite nicely through the thick bass. Cymbals, for example, are well separated without being too bright or piercing. With some music the end result can be fun and powerful sounding, whereas many times I would prefer less bass and smoother upper mids. The multi driver setup is interesting, as it makes the bass, mids and treble sound like they are coming from different places.
Deactivating Hell Blocker adds more bass bloat and softens the sound so that bass feels less impactful. On the other hand, this way mids are not too aggressive for me anymore.