Yeah, I went ahead and took the "buy once, cry once" approach with my cables after my second set failed in one channel.

V V V

I do my studies in public spaces that already have an appropriate sound floor (talking, ac, etc.) for me to use open back headphones without disturbing others.

Plus im not blasting them, I often listen at low volumes.

Exactly my goal, and I think I succeeded.

You're in luck, I also have both the DT770's on hand as well as the DT990's. I just spent the last 20 minutes scrutinizing all 3, and I would say the 990's are a teensy bit wider than my 6XX, but the 770 is a bit narrower than my modded 6XX. (No EQ or Crossfeed)

I would add though, that in my possibly biased opinion, my 6XX's now respond well to crossfeed in the L and R channels. I've sometimes played sound in them thinking my monitor speakers were on instead!

I cant wear these in public anymore

I got my inspiration from this guy who runs a business selling cups like these.

http://www.headphile.com/

Going closed back inherently narrows the soundstage. In this case though, Im assuming that it doesn't narrow it quite as much with the amount of room the wide earcups allow.

The wooden earcups have 3D printed waveguide cups, which make the listener's ears the focal point.

Im not super technically inclined, but I think that making them closed-back made the bass more prominent while not sacrificing soundstage as much as a traditional closed back would.