ATC or Audio Note (2-way)

I've owned both

ATC SCM11v2s

Audio Note AN-K SPx/SPe

Two very different price points.  The ATCs are very resolving, fast transient response, can play really loud and still maintain tonal balance and soundstage w/o compression.  They do need power to wake them up - so low level listening was their weak point, imo.

GR Research did a video on these for mods - their freq response is down a bit on top (I would agree), the mod evens this out.

AN-K's are much more efficient - best way to describe the sound is natural, relaxed and tonally 'right'.  Just as resolving as the ATCs, but they play better at low to mid-high volumes.  They don't do as well loud, imo.  I've not seen any measurements on the AN-Ks, so can't comment on mods.

ymmv

Thought both were very mid-centric?

no

ATC's are not midrange centric, they are not "smiley curve" sounding as so many speakers are.  Smiley curves sell MUCH better than flat speakers so they are vastly more popular.  Manufacturers know this as most are not in the business to build the best speaker, but to sell the best selling speaker.  If you like music, bass boosted smiley curve actually reduces resolution by elevating bass unrealistically compared to "heart" of the music: voice, piano, violin, guitar.  The midrange now sounds reduced, pushed in back, not like the band or orchestra or instrument really sounds.   This is why many in the high end "accurate" camp use piano for demo.  Its easy to hear changes to EQ on piano.     

Makes my head hurt that you would consider modifying a $13,000+ two-way speaker like the Super K’s having never heard them. 

+1 @ghasley

atc and audio note are the among the last speakers i would ever consider ’modding’

but hey its a hobby so peeps gonna do what they wanna do to be happy...  who are we to judge