The OKCSC ZX-1 is a weird one. I absolutely hated them out of the box, both looks (was expecting that) and the sound. They have a huge dip (>5db) in the lower midrange that sucks
all the life out of the music for me. I tried to pad roll them with tried every pad that would fit (I have a lot, lol). I ended up settling with a cheap velour pad that I originally purchased for my 990 Pro but didn't use for them because they were far inferior to the stock pads. They looks similar to
this llisting but I only paid $5 for my pair. This pad fixes the midrange and doesn't ruin the rest of the sound so I call that a win. Also, I know a talented quilter and she was nice enough to sew on a quilted headband cover. I still hate the cable but I can live with it. This is what they look like in their current form.
Cross-posting this for ZX1 users because I've just received similar pads and wanted to post some thoughts.
This styling definitely aids the midrange, both where it dips, but also where it peaks in the upper mids and comes off grainy. The graininess isn't gone, but in concert with the dampening of the lower treble, it's vastly more tolerable.
Unfortunately the side effect of all this is two-fold in my case:
1. there must be some taming happening at 5kHz because the soundstage seems to be somewhat more narrow, and in a headphone that already lacks a great deal in the upper treble this can leave it a bit lifeless at times; the existing treble detail takes a hit too
2. the area of bass bloat is shifted squarely on top of where kick drums reside, and it can completely destroy the enjoyability of some tracks
I say 'in my case' because the foam used in these pads is incredibly stiff, and I suspect that is contributing to both the heavy-hand on the treble dampening and bass boost. So the velour pad has a lot to contribute, and I suspect a combo with softer foam and maybe sheepskin leather would bring the lower mids in a bit.
Along with the pads came a couple of flat bits of foam for tuning, something I once wanted for a second set of ZX1s I originally intended to gift to a friend before I started revealing their many flaws. That set has the wrong dampening material in front of the driver, and while it has some better clarity in some aspects, it is absolutely grating in that 1.5kHz-4kHz range where this driver struggles.
It seems that you're always compromising with this headphone when it comes to detail level, basic tuning and pad rolling, and that probably reflects the driver inside probably not being suitable as a single driver solution (and thus not much of a headphone driver). With the OpenHeart OH2000 now appearing in this price range and the soundstage width of the Takstar Pro 82 and GM200 also around this price point, it's really hard to recommend this headphone any more.
That straight after that you have the AKG K361 @ $80 on sale and the AKG K371 @ $105 really dials down any value it has for those looking for a good entry-level can. Some might like the lower treble energy in certain situations, but I think it just winds up destroying upper-register female vocals in all modern and too many older recordings.