Sony MDR R10 - Reviews
Pros: Beautiful, pure and tonally perfect midrange; ZERO grain and brightness/sibilance; easy to drive; exquisitely made; supremely comfortable
Cons: Not the last word in perceived tonal detail or bass energy; I listened to a pair (see review)
I recently had the honor of fostering a mid-production pair of bass-light Sony MDR-R10s in my home for a few days before sending them to my friend overseas. While I wasn't able to listen to them for an extremely prolonged time, I did have some time to listen to them with my system and with my own music. And I'm delighted to say that this headphone indeed lived up to its hype of being a dynamic legend. 
A Brief History
The Sony MDR-R10 was conceived and designed as a sort of halo model or flagship product from Sony and its designer, Koji Nageno. The headphone was first unveiled in 1989, and production continued until the 1990s, with a total production run of 2000 units. There were a few iterations of the R10, notably a bass-light and a bass-heavy model. I listened to the bass-light mid-production model made sometime around the very early 1990s. The original cost was $2,500, which when calculated to today's money after inflation, is a little under $5000 dollars. 
Being a flagship headphone, the R10 comes with its own vinyl (or possibly leather) suitcase with two lockable spring-opening clasps. The inner lining of the box is a red carpet-esque crushed velvet, with a jewelry box-like compartment to store the cable and a few accessories. Inside the box is a metal plaque with the Sony MDR-R10 moniker stamped into it. This is a serious case for a seriously expensive headphone.
The MDR-R10's design, build and materials make it a true work of art; most other headphones feel like plastic toys in comparison. The headphones with the cable included weigh about 1 pound, or a little over 400 grams. The bales and structure are made from magnesium alloy, and the pully-tensioned headband hammock and earpads are made from Greek lambskin. The inner structure of the headband is made from a shape memory alloy. The cable is double sided, ten feet long, terminated to a 1/4 inch stereo plug (with the classic Sony green poles) and is made from oxygen-free copper with a silicon inner coating and double-woven silk outer skin (meant for strength and lessening static electricity buildup in colder, dry climates). Most notable, however, are the wood earcups. They were the first earcups designed by 3D modeling, and were harvested from a 200-year-old Japanese elm (Zelkova) tree. When you see the cups you will notice they have a matte sheen, a light orange finish, and if tapped, sound hollow or almost plastic-like. This is due to the resonant properties and rigidity of the wood, as it was harvested during the winters in Japan when the trees contracted the most to rid themselves of excess moisture from sap. This tight wood pattern is evident when you closely view the cups, and the tightness maximizes the resonant properties of the Japanese elm. Also note the shape of the cups. Rather than being simply half sphere, the cups have a flat back surface, and the backs are angled away from the ears to optimize sound, along with the angled drivers.
The wood cups are more than just a cosmetic piece. The designers meant for the wood cups to serve act as acoustic chambers, rather than relying on an open back design. This was truly an innovative headphone, particularly among the closed back section. The R10's innovation in use of wood for acoustic purposes doubtlessly inspired Denon's AH-D5000 and D7000, Fostex's TH600 and TH900, and Audio-Technica's wood headphones. 
The drivers used are biocellulose, which unlike mylar, do not suffer from the same issues of harmonic distortion and modal breakup. Despite using an organic, bacteria-based material, the drivers remain in excellent running order and show no signs of deterioration.
What I especially like is the lack of tacky badging all over the headphone: just the model name in small letters on the metal cable y-splitter, the word Sony engraved on the metal bales, and the model number and word Japan etched on the inside of the band. It's very much like a Bentley or a Rolls-Royce: no excessive badging needed to announce its presence.
If car analogies are fair, the Sennheiser HD800S feels like a 2016 Porsche 911 GT3 RS, while the Sony MDR-R10 feels like a 1963 Ferrari 250 GTO. 
Comfort and Isolation/ Sound Leakage
The R10 was designed to be a flagship headphone, and thankfully the comfort is also flagship worthy. The R10s are probably the most comfortable headphones I have ever put on my head. I have big ears, and while the earcups are shallow, the pads are broad in surface area to distribute the clamp across the side of my head evenly, are soft, and are angled to provide additional space. I noticed my left ear did slightly touch the soft screen lining of the left earcup, but this was no problem. No clamping aches, no jaw pain, and no migraine-inducing temple pressure to be felt here. The weight of the headphone is slightly more than some more modern headphones like the Sennheiser HD650, but the design is so wonderfully balanced, the R10s stayed put on my head while showing no front or back heaviness, and with little clamping force needed. The headband cradle is simply icing on the comfort cake, distributing the weight across the top of my skull with ease and no pressure to be felt on the ridge of my head. 
While it is a closed back headphone, the R10 exhibits little to no sound blockage, and has a modest amount of sound leakage. So don't expect it to be a portable headphone; this is an at-home-only headphone. 
When I plugged the R10 into my Schiit Audio Lyr 2 hybrid amp (sadly I didn't have flagship gear to play with), I just heard music. The R10s didn't sound all that painstakingly detailed like a Sennheiser HD800 or Stax SR-009 would sound, and they didn't have the speaker-like bass impact (in fact they might sound a little shy compared to newer headphone) like people associate with Audeze headphones. They sounded like music. These headphones do not jump out at you with obvious detail or big soundstage or bottomless bass. But then it dawned on me what was so special about the R10s: what I did NOT hear. I didn't hear grain or stridence, literally NOTHING. There isn't a single microscopic bit of graininess to be found in the R10/s sound. The treble while detailed did not sound in the least bit hyped, artificial or elevated. It just sounded like treble, but it wasn't rolled off, dark or veiled either. It is beautifully effortless and unstressed treble that lets you hear the tone and detail, but never sounds sibilant or irritating in the slightest. It was easily the best treble I have ever heard on a headphone. Just so dead neutral. 
The bass on this bass-light model did sound a little lean and was not ideal with artificial or hyped synthetic bass like you will hear on most of today's Top 40 or dance music. But listening to some good quality electronica such as Thievery Corporation or some jazz rap from A Tribe Called Quest showed the R10 capable of delivering beautifully clear, musical, if not a little lean at times, bass. Again, while not nearly the biggest quantity of bass I have heard on a headphone, the tonality of the bass was outstanding with the right music, and was stupendously accurate when the song was mastered well. 
The wood earcups serve as acoustic chambers, creating a somewhat intimate, but neither congested nor diffuse-sounding image and soundstage. The soundstage of the R10 is somewhat similar to a home summit-fi speaker system in how it is presented. While it isn't going to sound obviously airy and expansive like a Sennheiser HD800 or AKG K1000, the R10 does not disappoint, sounding wonderfully personal when I listened to it, and about as close to being at a live performance as I could be
But the crown jewel of the R10 is the midrange. You buy the R10 for the midrange over anything else, because to me, this is the greatest midrange I have ever heard on any headphone or speaker system, and will probably never be surpassed in my opinion. So many headphones have a tone to singers and mids that so often sounds like listening to electricity and equipment piping the sound of someone singing to you. In other words, the experience sounds slightly removed or a little uninvolved, and takes away the magic of being there to hear the singer's emotions he/she conveys. That's where the R10 comes in, because I have never in my life heard a more tonally realistic headphone for vocals and mids. Listening to the R10 doesn't sound like a speaker playing Eric Clapton singing Tears in Heaven, it IS Eric Clapton singing Tears in Heaven, complete with the somber, pained emotions he felt when writing and performing the song. It's this soulful, intangible experience that frequency charts or scientific explanations just cannot fully explain. You listen to the R10 with your heart, not your brain, and you don't try to measure it, because thinking or trying to rationalize it will likely leave you scratching your head or even dismissing it. That is why I call the R10 a Stradivarius. There is just something there that people just haven't been able to objectively quantify or explain why it sounds the way it does. While the R10 isn't the last word in perceived detail, that is OK. Because you do not listen to artists perform live and hear their performance analytically or with an aural microscope. You listen with your heart. And that is what the R10s do flawlessly.
Now for the biggest negative about the MDR-R10...
I listened to it. 
With prices reaching in the astronomic thousands, and few people wanting to let theirs go, I don't think I will ever be able to own an R10, even when/if I have the big dollars in the future. And it makes me sad to see that I may never be able to experience this wonderful time I spent with R10s I can call my own. But I am truly delighted to know that I was able to listen to the best of the best, and know that there will likely never be a better sounding headphone I will listen to in my life. And it is reassuring, because I know I have experienced the Nirvana (the Dharmic nirvana, not the band) of headphones, and know now there is no need to lust for something more or attempt to strive for something I think may be greater. This puts an end to the chapter in my headphone-addicted life of wanting to lust after the most realistic sounding headphone. Though I may never again experience such a beautifully emotional and transparent headphone like the R10 again, I am delighted to know that I had the experience. I caught the magic dragon, but then had to bid him farewell and let him run free. To have a beautiful experience and come to terms with the emotional feeling of never having it again is still better than never having the experience in the first place and wondering what the fuss was all about. While I bid farewell to the Sony MDR-R10s, I can now put to rest the yearning for something better, and come to terms with knowing I may never again have that personal listening nirvana.
Thank you all for your time, and have a wonderful day. 
@TheOneInYellow Well I surely hope for a future with audio that can replicate the listening pleasure of the R10, and not just try to achieve it by boosting the bass, sampling rate, or treble volume.
this is what i dont get ,these are the best looking headphones iv seen ,im a sucker for wood and those wooden cups and the angles just look ,wow .if sennheiser put a wood cup on like the hd800s i recon they d sell even more of them .anyway but these things look and apperently sound great m why does ent sony still make them ,theres gotta be another 200 year old elm they can cut down during winter .if sony still made these id be more interested in them as headphone manufactures and maybe even buy one of there cheaper models
My dream as a headphone enthusiast is to own both, the bass heavy and bass light R10's, or at least listen to them. Both possibilities are far away from me right now, but a man can dream. Excellent review. :)