So as I've said, owned an X but their frequency response was esoteric and their fit was... problematic.
Got these in for review and so far I'm absolutely loving them. Basically like an HD600 but with more technical prowess and bass extension.
Idiosyncrasies to look out for are:
1) the upper midrange increases with more clamp (and they are already quite a clampy headphone on my medium-small head) so if you have a bigger/wider head, it might be a bit shouty for ya.
2) It's a planar so it tends to sound more "the same" across the sources pro audio people are normally using, feel free to use this one on your Macbook headout.
3) IME planars don't do the middle/end of ADSR quite faithfully. They're
great for hearing the absolute front-end of a note but the decay kind of gets truncated on this kind of transducer.
4) It, thankfully, doesn't tell any pretty little lies with regards to the headstage here; no blown out HD800 or Hifiman width. It's very fair and nothing more, which is ideal. Anything more is making it sound better than it is.
5) They might legitimately be too good.
What I mean by the last part is, funny enough, I don't necessarily find them ideal for production/mix/mastering work. They're incredibly technical headphones (speed, control, detail, it's all there for you) but that might make things sound better than they are.
I also find the frequency response here smooths the 4-5kHz and ~10-12kHz areas enough to make vocals in particular sound more polite/un-sibilant than they actually are. That being said, 20Hz-4kHz here is about as flawless as it gets in an over-ear transducer.
The 4-5kHz and 10-12kHz recessions are
extremely welcome since I'm especially sensitive to these regions. In fact that's how I know it's recessed there; as someone who's heard basically every current production Sennheiser, Focal, Audeze, Hifiman, DCA, Beyerdynamic, Sony, etc etc headphone, they all tend to have weirdness in those regions that makes them not fit for more relaxed listening. MM500 has recessions in both areas, almost as if it was made for me.
My advice for mixing? They might be too well-tuned and smooth for the task, but they'll still be better than most cans people use (Beyerdynamic, Sony, Hifiman etc. all basically useless due to the treble). Stick a 4dB low shelf around 82Hz to emulate room gain if you want it to translate a little more accurately.
Make sure not to use linear phase mode if you EQ headphones btw, as headphones are minimum-phase systems per Toole's findings way back when. Explanation can be given upon request, but in short, minimum phase/zero latency EQ is the way to go if yr EQing specifically to compensate for a headphone's frequency response.
Also another misconception: these are easy to drive not because of their impedance (18ohms) but because of their being extremely high sensitivity. Other "low impedance" cans like Hifiman's HE6 are low impedance but basically need a car battery to run.
Luckily these can be run out of anything and sound damn good while doing it... perhaps a little too smooth for work but exactly my speed for relaxed listening
