I've been spending some time with them and yeah, that overblown mid-bass is starting to annoy me a little bit. It works with some material but can be too much of a good thing on others. It comes at the expense of actual bass depth so... not really a trade I'm interested in. Still as offensive traits go for recent Stax sets... this is pretty fucking mild and I do enjoy them quite a bit. Not replacing my 207's though...
So I had make a comparison for fun. I had probably the last ever B-stock Koss ESP/9X5's sitting in a box here so why not compare them against the Stax. Similar price category but the Koss build quality is nowhere near what Stax are doing. So the Koss needed some mods, gone is the cable and they now sport the setup from a King Sound KS-H4 (so removable cable as well) and those leather earpads you can get on Aliexpress. All of the stock damping material, which was minimized on these anyway, as well.
Fits like a glove and it's fun to compare these two, as aside from the HE60, these are some of the lightest and easiest headphones to plop on the head and enjoy. I've always liked the Koss as it always stood toe to toe against the Lambdas and this time it is no exception. It is more neutral and laid back, a bit more relaxed than the X1 but with better bass response. Larger drivers so it has more presence to it, more space around voices etc.
Speaking of the Koss though, I wanted to sit down a try the Massdrop setup directly out of the box and holy hell... what were they thinking with those earpads. I plugged them into my test setup and on the first song, "ehh where is the all the sub-bass?" Yeah, this didn't help with the BS that electrostatics lack bass...