I bought the Nighthawk Carbon back in the day to explore warm headphones. They were indeed very very very warm. They taught me something and spurred additional headphone purchases, but I eventually boxed them up. At some point my wife adopted them so they are still in the house.
I went back for a listen after a few years, and found they weren’t so warm and sounded neutral more than anything. Perhaps my hearing is going downhill, perhaps my source devices transformed them, or perhaps the headphones changed. I’m thinking their biocellulose drivers aged or matured or hardened, so I’d be curious to see a retest.
Their suspended free-floating cups indeed make the Nighthawk among the most comfortable headphones I’ve ever used.