I'm the one who measured the DT 700 Pro X, and I also wrote a first impressions here on the headphone subreddit if anyone here would like to read it (especially for my more subjective opinions):
https://www.reddit.com/r/headphones...t_look_at_the_beyerdynamic_dt_700_pro_x_with/
A bit scared to join the conversation, but I thought I can probably answer some questions regarding the DT 700 Pro X - well at least whatever I can. I've already returned them if that says anything about the headphones.
Regarding the 4kHz dip (and measurements aside), I can confirm that there is a dip here with my ears and an online tone generator. It is pretty severe as it just drops off. Whether or not one is sensitive to that dip is dependent on the person.
The MiniDSP EARS measuring system does indeed show artifacting around 3-5 kHz in most if not all headphones that are measured on it. It's a hobbyist's rig and although it is not be totally accurate, it gives a fair idea of what a headphone sounds like especially in comparison to another headphone measured on the same rig.
The MiniDSP EARS as I mentioned in my original Reddit post and in the Imgur measurement link shows artifacting around 3-5 kHz. You can also see it here on the HD600, HD650, and HD800. I picked these three since a lot of us are familiar with how they sound like. Now we (hopefully) know that the 3-5 kHz region on those 3 headphones does not sound like it looks like here. I should also note on the HD800 in particular here shows a peak at ~7.5kHz which is incorrect and that's also a limitation of the MiniDSP EARS in its inaccuracy in measuring the treble. The HD800 is infamous for its
6kHz peak.
Because of the artifacting in this region, it is very hard for me to compare headphones in this particular region solely based off the MiniDSP EARS measurements. Having measured a fair bit of headphones, I have an
idea of what to expect in listening when I see other MiniDSP EARS measurements but I wouldn't say I'm 100% confident. The artifacting is bad enough that I would say to disregard the 3-5 kHz region with MiniDSP EARS measurements especially if you're not familiar with the system.
In conclusion and going back to the DT 700 Pro X, the MiniDSP EARS shows a fairly big dip/null around 4 kHz on the DT 700 Pro X. Even with the MiniDSP EARS artifacting, I do think the null there is actually there when I used an online tone generator.