In short: the treble of the hifiman edition xs is hella piercing, especially for edm track. Is this a feature of the headphones or defective?
So i just got the hifiman edition xs yesterday, and damn, it is such a surreal experience compared to the dt 770pro i had. Everything sounds way too clear - i can even listen to the bass player in a well recorded metal song. I didnt even plug it into an amp, yet the bass rumbled much lower than the dt 770 pro. It seems that edition xs is only a bit harder to drive than the dt 770 pro, so i suppose i dont need an amp. However, when it comes to high notes in edm track like a future bass song, the edition xs just sounds so harsh that i just cant stand it. Well, it doesnt really sound crackly to me, its just overly peaky. Is it a common thing for the edition xs? And the wire it provided sucks.
There is a risk that 18 ohm edition xs shows bad behavior with some amplifier outputs. If you have been using DT 770 Pro with 250 ohm impedance, there's a good chance that the same headset amplifier, especially if it's just some random laptop output jack, does not necessarily play as well against this much lower impedance headset. I recommend getting a low-cost amplifier like the 3.5 mm Apple usb-c headphone jack adapter which is decent amplifier with a known-good behavior, and in particular it has low output impedance, just to confirm that it still sounds the same. Sometimes, these headset jacks in laptops or computer monitors are just poor, for instance they might have some kind of DC voltage offset elimination capacitor that have too low values, or whatever, which could definitely create treble-heavy presentation if an unusually low impedance headset were plugged in them.
Compared to Harman target, Edition XS should be overall closer than 770 Pro, from what I can see. I think there are only two tonality issues: there is not enough bass to sound natural, and there's no 1-2 kHz region boost, which are fairly common features on open-back planar headsets from what I've seen, whether made by Audeze or Hifiman. I think you need to engineer some kind of acoustic resonance or resistance to alter the sound, or you just get the default, and open-backs are in poor position to manipulate the sound as the technology is very simple, basically a straight wire through a thin membrane with linear movement characteristic as function of voltage and no back-pressure given by a cup. I've heard that Dan Clarke has some kind of complex metamaterial providing a sort of analog equalization for his open back headsets, as an example.
Finally, when looking at headset measurements, I encourage disregarding any measured performance at about 8 kHz and above. The data simply isn't reliable, as frequencies so short are similar to the distance between headset's cup and the artificial head, so there will be distortion in the measurements for that reason. My guess is that this is also why sometimes changing the pads help, as pad thickness might vary, and that could well change the distance between the headset and the head, and perhaps changes the resonances experienced by user.
I did get alternative cable for Edition XS. I agree that its default cable is surprisingly crappy for what is a fairly premium headset.