I think the 400i's performance is solid with lower volumes due to their exciting nature, but perhaps they are relatively thinner then, as you said it: you can add a tad of heft/tonal thickness via increasing the volume. Their nature does change a bit with adding the volume, which is kind of a flaw. I found myself ramping up the volume with 400i every now and then, which I don't need to seem to do as much with the LCD-X, as volume change is just a linear, effortless thing without losing/adding anything at all. And of course the LCD-X has some flaws as well.
And about that giving time thing: yeah, coming from dynamics to your first planar, it takes a while for your brain to understand what's going on. Coming from a thinner, and extremely bass rolled-off AKG Q701, I thought the 400i was bass-shyer for the first few weeks. Seriously.
And electronic music on the 400i, I agree.
The unnaturally quick transients, impulse response and the treble attack with well-produced electronic music can be a euphoric experience. Combine that with the artificial treble peaks, the 400i just forces you to listen, and focus. That comes with a price: badly produced stuff does sound awful.
I feel the 400i is quite genre-dependant (due to the unnaturally quick transients, harmonics, FR tuning etc.), and obviously production-dependant. Then again, I think the 400i is quite a good all-rounder nonetheless; but I'm annoyed by the fact that some genres cannot achieve those euphoric highs - some stuff actually sounds quite off. But then again, which can is very good with everything for your personal tastes.
And generally speaking, the detail in the bass is incredible. Way more than anything else in the price point. Perhaps it's just on the verge of what the driver can actually do, as boosting bass take some detail in the timbre away. And yeah, some electronic music could definitely use some tonal thickness. 400i cannot do that. It's not a slam monster by any means.
Regarding these observations vs. the LCD-X. The LCD-X isn't as exciting in the sense of forcing you to _listen_ all the time. Pointing out details all the time. The detail retrieval is undoubtedly superior to the 400i, and effortless - but you're in control yourself, if you want to focus on the details, they're there, and it's a joy to pick them out, but if you just want to get lost in the music, you can do that as well. And I'm talking about the least romantic, lush and musical of the Audeze line
Still haven't got the amp sorted out for this at home. Work in progress!
And yeah, did I mention the face-melting slamming properties? It feels like two speakers wrapped around your head in plush lambskin leather. Weighing like the beforementioned speakers. These things even have some speaker-like forgivingness going on as well. I have yet to find any record to sound awful, it's often vice versa. Did some gaming to pass the time at some point, and I actually enjoyed some hideous music which was in turd-like quality. It was an odd experience.
And yeah, exactly what I was after by mentioning the reference point! Thinner than the HD650, but thicker than the general AKG/Beyerdynamic tuning.
I hope my rambling was helpful to you/others.
The 400i does make very good value for the money. It's good value against the LCD-2; but then it comes down to the personal preferences about tuning. It's just nothing like a budget LCD-2. (The very early impressions seem to point that the M1060 might be, though the thread seems to be flowing with bodily fluids due to the ongoing circlejerk, can't really decipher any proper information out of it!)