Headfonics review of the DK-4001
https://headfonics.com/dunu-dk-4001-review/
"Quite a lot of hybrid signatures out there give a solid focus on a high-contrasting sound between the bass and highs to produce a ton of excitement. The DK-4001 plows a different path with a more balanced tuning. It a real grower and gets some sold playback time with my neutral DAPs."