How about some reincarnated headphone tech from ancient times? I joke, but not really. I swear people forgot how to make planar magnetic headphones between the first Fostex planars in the 70's and the modern takes we have now. For a while there, they were just bad. The drivers are very simple, but the process is pretty precises. Often they would break, or just have inconsistent sound. One $2000 pair of headphones sounds like a reach around from god himself, while another sounds terrible. Tonally, they were all over the place. And so inefficient some required speaker amps to drive enough current, needing more than 1 full watt of power where other headphones are about ready to catch fire in the milliwatt range. The comfort sucked, nobody knew how to build enclosures that made them sound good or sit right on your head.
See, there was no huge body of information or fleshed-out procedures for making them. It was wild-west back in the day - planars had a lot of promise but at that point were more of an engineers wet dream than something practical and affordable to make. Good ones are still expensive to make. Companies like Audeze and Hifiman are not experts at making these any more than anyone else alive is. They had to churn out about a dozen iterations each before they started getting things right - I truly believe they had no idea how to make them, and that's still kind of being decided now. Most headphone drivers aren't much bigger than the smallest tweeter on any speakers. Planar drivers can be wider than the woofers on some of those same speakers. My HD6xx have a 38mm driver. The LCD2C is 106mm, so over 4" across! The physics behind that are undeniably beneficial. Theoretically they should be able to best dynamics in pretty much every area.
But that planar is a unicorn. Getting there is apparently pretty hard. Just so many different factors and ways things can go. If you can make a good driver, you can't design anything around it. And if you have a good design, you can't build enough consistent drivers to roll it out. I avoided the things like the plague for years, they all had so many problems with sound and longevity.
Once upon a time, some dudes were like "What if we took a regular voice coil/diaphragm assembly, stood it on its edge, and squished it flat?" And somehow they actually did it. Took a thin membrane wired up with traces and put some magnets behind it (or sandwiched it between two arrays.) Brilliant in some ways. In theory, you get a flatter, thinner diaphragm that's got 3x the surface area of a regular dynamic driver - which translates to lower excursion and far lower distortion. Somewhere between a dynamic headphone and an electrostatic headphone. Just gotta build the enclosure that damps them right, balance the mass/tension of the diaphragm to control resonances, tweak the positioning of the magnets, the geometry of the traces, shape of enclosure, pad material/thickness/angle... ...safe to say, it didn't work out - mostly forgotten for a coupla decades. And then revived for the new-school headphone enthusiast markets. Past decade has seem them come a looonnng way.
...yeah, I think we are actually just now at a point where modern planar magnetics are beginning to match the engineering that went into the early planars. And I think they sound the best they ever have.
At this point there are a couple of manufacturers who finally have their processes worked out - they can make good, well-tuned drivers with one of a kind performance that lasts for a long time, in a package that's actually comfortable and worth the money. Audeze is up there as far as those go. No dynamic drivers come close to the generally sub 1% 'flat line' distortion that their headphones tend to have, and the sound is a totally different beast. They just have this command of attack/sustain and lower frequencies that no dynamic headphone is ever touching. Good planars, to me, are warm, full, smooth, clear, detailed, and energetic. Their newer TOTL stuff is more lean and heavier on treble resolution, but they've still got that 'it' factor that has to be heard to be understood.
Love these things, look pretty serious stealthed out in all black. I think I actually prefer this over the wood cups of the LCD2's. Look and feel more solid.
Pretty much everything that can be metal, is metal. Only that outer ring is nylon, and it's a really sturdy nylon. These are heavy and feel like a brick. All of the mechanisms are smooth and sturdy. The suspension system distributes weight well, and with the thick memory foam pads with super-soft synth leather, wearing them on your head is like getting a lightly overly-affectionate hug. They're basically ALL pad. You have the little grill/magnet/driver sandwich in there, some knobbies for the 3-pin xlr's, and then the other 70% is soft, squishy pad.
That material really is amazing. I didn't know something could squeeze my head so tightly and still feel so comfortable. These are open-back, but they seal around your ears like closed-backs. Soundstage still like open backs, but a little more intimate.
Sound isn't for everyone, they're warm like Audeze's older planars. But they do have that amazing planar bass. One of the biggest advantages of this type of headphone is in the distortion and FR characteristics. These are totally flat in frequency and distortion from 10hz to 1khz. Like, the chart is literally just a horizontal line. It's basically the discerning basshead's headphone. It's not overpowering bass, but there is a lot of it - it's full, clean, extremely responsive and doesn't take away from anything else. It congeals to the mids in a way I just can't explain. It sounds both very fast and very round at the same time, it's just got this taut slam to it. The bass and midrange just have this dynamism and energy. Rock percussion and detuned electric guitars sound meaty as hell. Overall it's just a sound with a lot of body and life down in the lower end. Typical downwards slope towards the highs, so they don't have that shimmer. Plenty of detail in the mids and it's a nice laid-back sound. Any kind of processed music sounds clean and alive, even though the tone is slightly dark. It tames problems in the presence region before boosting at ~7khz. Not coming in too hot, just a little sizzle.
It'll throw you off, it's a confusing tone. But for some music I feel like it might be the best I've found. This tone seems to give very dense and instrument-heavy music incredible instrument separation. You really hear every instrument distinctly, and it's coming through with this smoothness and fluidity that sounds like very few other headphones these days. Older planars nailed that too, but tended to be too syrupy/mids-heavy and dirty-sounding in the highs with nasty, weird peaks. With these, you lose that last bit of resolution in the treble, but you really gain a lot of that detail back elsewhere, plus a little crunch in the treble that's generally pleasant. It's the polar opposite of how an HD800s presents detail. More natural, less analytical. But still digging pretty far into the sounds. Because it's so laid back, it's like everything has room to breathe. It's just not adding any extra air. So you don't have that 'peaking-out' where the sound seems compressed, like sometimes there's too much going on.
These things are basically made for rock, metal, hip-hop, electronic music, pop... anything that's meant to be really high energy and rhythmic. The busier and more rhythmic, the better. Just winds up sounding HUGE and defined. The way that the bass and midbass just interlock with everything is awesome. Really visceral, without ever being aggressive-sounding.
wtf, i Paid for fast shipping/delivery, so called Amazon and explained what happened so they apologized and gave me a refund, the funny part is that the package should be delivered tomorrow but today i got another notification from UPS where it said that today the package was left at a UPS access point and was ready for pickup 
I tried offering $500 but no answer.