If you check into many of the other Koss headphones they have a peak in the same area. The MV1 one has a larger peak than what the DJ100 has.
The graphs of the MV1 on the Goldenears website are disturbing.
Have to admit it but the DJ100 sounds to me like a mix between an AKG Q701 and an HD-650. The DJ100 still has more forward lower bass than both though, but barely. The upper mids remind me of the SR-225i.
The 65th aka "Annie" is closer to the DJ100 if you give the 65th more low bass, more warmth and more forward upper mids. The DJ100 definitely has more treble than the Annie and HD-650, but not the Q701.
Sorry for my english, but a peak is the opposite of a drop, right?
Isn't that a massive drop in this graph here below?
And yes, you're right, every drop creates a peak just beside (and the other way round), a huge drop at 5k will subjectively boosts the above and below frequencies.
For me, the closest phone to Q701 is HD-662F (kinda closed version of it), tdock, I bet you would love this headphone