I was first attracted to these beacause of their looks. I always like a detatchable dual sided cable. The ribbon black and yellow cable seemed to be trying something new (think, the opposite of the HD 700 cable). Add to that, the term Flagship was bandied around so I thought I'd roll the dice. I had read some positive reviews, but Wow, these came out of nowhere. Talk about a dark horse. The distribution in the US is terrible. I bought them for about $400 from Accessory Jack out of HK. The packaging is ho hum. Pulling out the headphones for the first time is like getting to sit in a Bentley Continental at the dealership; just feel the luxury.
The first thing that stood out to me is these babies are weighty. Those are metal cups, metal head band, and I think leather. Pulling out the cable, it's long, it's flat, it's rubbery, and it is strangely beautiful. Big velor ear pads and a little too clampy. So, I let them burn in a little while on my headphone stretching block.
The first couple of songs I listened to, I was't sure about. I have a folder of test tracks that are like an obsticle course for headphones. Then I remembered the free Hi-Res music offer that comes with these cans, so I downloaded some of that stuff. Wow. Just Wow. OK, now we are in business. I brought some other cans to compare with, got some amps for pairing, and started to do what I love: listening very carefully
First observation, the bass is not anemic like on my HD 700. These are open, and noise isolation is poor, but the detail retreaval is amazing. I don't know how flat these are graph wise, but the sound signature is very pleasing, very musical, and I did not hear anything spiking or being pushed forward. Even the bass seems just right, not bloated like my Z7 or anemic like my HD 700, but just right.
Oddly enough, the weight of these that I thought would be a problem evaporates with that huge, luxury head band and plushy earpads. The clamp force was easily tamed by one night on the block. I don't think the sound stage is quite as big as my HD 700, but not small in anyway, more focused. The sound appears very 3 dimentional. These are real contenders. I am glad I bought them. They can't beat my Z7 for comfort, or my HD 700 for air, but these cans have a balanced, accurate sound, top notch construction, striking good looks, and the comfort of real luxury. I would buy them again for $400.
I am writing this review because I took a chance on these and it really paid off. I wanted the industry hype to be true, but I have been disappointed before. This is one case where the testamonials are accurate. I think that these are going to be rare very soon and I am glad that I got them. Plus, it is easy to get on the band wagon for the flavor of the month, but I like to take a chance now and then and back a dark horse: the Onkyo A800M.

      This is exactly what I have been looking for; a well made, comfortable S500. I have bought a lot of head phones looking for this. 40mm titanium Hi Res drivers. Closed back with a bass port. Metal headband with infinitely adjustable slide. Soft pleather pads (40mm x 57mm) My ears fit without touching. These arrived today. I've had them burning for a couple of hours. They sounded good out of the box. I am listening to my headphone test songs as I write and two things stand out: These are VERY comfortable, and these Kick *****.
    A little bit about me: I have enjoyed most types of music at different times of my life. Early music, Classical, Jazz vocals, Difficult listening music, Punk rock, Classic rock, Folk, Blues, Metal, Grunge, Miami Bass, Dub, Dub step, Trap, EDM, Euro Vision ... I also make music, and that is why I got into headphones in the first place. I make Bass music for "the cars that go BooM" (Db Drag Racing). The closest equivalent would be Miami Bass. I have a great monitoring system, but not everyone wants to hear me working on a song for a couple hours that has it's central focus at 50hrz. and literally shakes the glass in our building. Getting headphones that can recreate a good car audio system is not easy. My first cans were Sennheiser HD590, that was probably 15 years ago. I still have them, they are excellent. There are plenty of headphones that can recreate sub bass, and there are plenty of headphones that can recreate crisp highs and seductive mids, but there are very few that can do both equally well; and this has been my quest. So many have seemed so close, but there is Always something missing. The JVC HA-S500 came the closest so far, but they are so uncomfortable to me that I can only wear them for 10 minutes at the most. 
    On to the JVC Solid Edge, HA-SD7-B: For me, they are the HA-FXT200ltd of over ear headphones. Very Tight, Very fast, Great sub Bass reproduction, They sound very similar to the JVC HA-S500, but they are way more comfortable and have a real quality build. I think that these will be dismissed as fashion cans because they come in 3 colors, but that would be a real mistake. These are solid performers with an edge, a Solid Edge. There is almost no information on these cans in English, but on the back of the box it reads "Pops, Rock, Anime, and Dance" along with the international symbol for each of these genres. More camouflage I suspect. For more information translated, check out my introduction thread.
 
    I want to thank all of you at head-fi for a most Homeric education. "How do you thank someone who has taken you from crayons to perfume? To Head-Fi, with love."
     

    I like these just a little better than my Sony MDR XB90ex, which I think is saying a lot. They both have a very ergonomic design that allows them to stay in ear securely and comfortably for long periods of time. They both produce gobs of sub bass, but I think the MDR XB70 has better presentation over all, even with more bass than the venerable MDR XB90ex. Now, I understand that I may get flamed for saying that, but to my ears the XB70s just sound more dynamic and pleasing, and in reality, I grad my XB70's three out of four times over my XB90s. The only reason that I brought the Sony MDR XB90s into this review is that I expected people to ask: "How do they compare to the XB90s?"
    I have both the MDR XB70 and the MDR XB70AP(Apple Phone version) I vote with my dollar, and I bought two of these. 12mm dynamic driver, some metal, but mostly plastic. The cable is thin and flat ending in a nice right angel plug. The plug is narrow but I can't be sure that it will make it past your phone case (6.5mm) Nice solid Y without being heavy, plus chin slider. All of these elements appear to be designed more towards light weight and finesse rather that over engineered bulk.
    How do they sound? I have been listening to them the entire time I have been writing this, and I am really surprised at how good these sound. They have a very full and complete sound signature, the 250-500Hz gives the kick drums a very crisp attack, more so than the XB90s. The mids and highs appear a little recessed, but only compared directly to something fantastic.Actually, once my ears adjust, these are very full and even, and feel non-fatiguing. They remind me a lot of the Sony MDR XB950 over ear cans: both are very comfortable, non-fatiguing, and just less than magical but entertaining.

    I am writing this because I have read so much more than I have written, and I believe it's time to give back. There are two new versions of JVC's famous Bass iem: The FX99X and the FX77X, I am glad that as I have grown in this forum and hobby, my critical ear has developed and I can appreciate different sound signatures. I began this journey in search of "one can to rule them all".  In its place I received an education and made new friends. I can hear things today that I was unaware of a few years ago (thanks Head-Fi). That is why I am so glad that JVC made a High Rez Bass iem. But, did they do it right? Yes! The sound is amazing, full, rich, balanced, fast, capable. Capable of reproducing amazing sub bass when called on, without distortion. Capable of presenting very clean acapella male of female voice without coloration. Capable of acoustic strings, piano, violin, without mud or veil. 
    In short:
    Sound is just ahead of my HA-FX1100 and just behind my HA-FXT200 ltd. 
    Comfort is very similar to the FXT200ltd. The FX99X has a small "bump" towards the rear to help it stay put. This works but also reminds me that I have an iem in.
    Build quality in on par with price, the right angle plug is metal and nicely detailed and well thought out, stepping down a little to allow use with phone cases.
    Accessories are limited, meaning three spiral dot tips and a pouch. I wear the ML Spiral dot tips so I buy a lot and have them on hand. I mentioned earlier that the pouch had been redesigned; 
              Strange the things that put a smile on our faces... It is just one of those squeeze open and snap closed affairs, but it doesn't snap closed. It slowly closes like it has air shocks or hydraulics. 
              I almost never use the pouches, and I have many of them stored, but I really like that some one at JVC went to the trouble to redesign this; it feels like quality and luxury. 
              If you are looking for a shirt clip, you don't get one. Who cares? Right? The JVC shirt clips are almost impossible to buy separately. I just ordered one for $20 plus a two month wait, for one shirt clip!
    I highly recommend these to those who can afford $150 and want an iem that sounds like car audio.(Clear, crisp, bangin')        
 
PS   Like all good cans, these benefit from good amplification.

     These are amazing. The best of all my iems. These really are the HA-S500s of iem. Slightly uncomfortable, but worth the hassle at any price. They are dual dynamic micro driver, like the FXT90, its predecessor. I use the Spiral Dot ML tips. These are gorgeous and well built without being heavy or awkward. As with most cans, I find these shine with proper amping. (Garage 1217 Project Polaris)
I listen to mostly Trap, Bass, EDM, but have gone through Early Music, Vocal Jazz, Classical. and can be seen listening to 60's/70's rock for reference.I have an amazing 4.1 system at my desk that I am always comparing my cans to. I have a lot of over ear, on ear, and in ear monitors. They all have their strengths and their weaknesses. I have stopped search for the "one can to rule them all" 
For comparison I offer the JVC HA-S500. These are about as fast, bass capable, and crystal clear as the S500's. They are affordable enough to buy a second pair, which I will probably do soon enough.
I am a tech whore so I love the silver plated OFC cable on the 200ltd. I have the HA-FXT100, but I would not buy a second pair. I really vote with my dollar. If something is so good that I don't want to live without it, I will buy a second pair as back up and keep them in the box. I just received my S500's but I will get a couple of pair and keep one in the box and have another pair cable modded. Back to the FXT100's: they are capable, but they are missing that "magic something" that puts a smile on my face.(HA-S400 anyone?) There is not a significant sound signature difference, but they are not a "F- Yeah"
The HA-FXT200ltd are.
In closing:
If you'd rather shred a Tuner car than a Euro sedan,
If you'd rather shoot a FN 5seveN than a Glock, then these will tear you a new one

      I am glad I got these, but I was reading a hype train from 2012. These are two micro drivers and a sub; sounds good, right? But good is not good enough. Especially at these prices and the amazing competition currently out there. They don't stay in my ears easily without a shirt clip. The Y junction is heavy for an iem. I have better sounding JVC iem for less money, but less comfortable.(HA-FXT200ltd)
They can handle a lot of sub sonic signal without distorting. The mids and highs seem separated and unaffected by each other or the Kelvin sub out back. 
    In closing, if you want to cut 6th period and smoke a fatty at your friends house and listen to his dad's awesome floor system for an hour, these are your babies. 
    If you want to get blown away by high tech iems, maybe check out the HA-FXT200ltd.
 
   PS   I am listening mainly to Trap, Bass, and EDM; not orchestral.

    The Sennheiser HD598 SE I believe is one of the most under estimated and under valued over ear mid-fi headphone at this time.I do not particularly enjoy writing reviews when there are far more experienced and confident members who I believe could shed a more revealing light upon these headphones. But they have more important things to do at this time upon which we at head-fi heartily rely. So I am sticking my neck out; going out on a limb, as it were, and only time will tell. 
     I believe that part of why these headphones are so under valued at this time is because they are being replaced by the newer HD599 and Sennheiser will stop making them soon. I think that the SE moniker in collaboration with Amazon is to liquidate all of the existing stock of the HD598 SE while it is still has popular value. And there is the point of this review and hopefully the benefit of the immense reading that I've done over the years past here at Head-fi. 
    A headphones true value is not the sum of it's frequency response graph, it's model tier, (5 series) it's current lowest asking price, or even it's claimed technological advances; I believe that it is the joy it gives it's users. How many times have I read here a member admitting apologetically that although owning the TOTL headphone that we all would kill for, that they find themselves reaching for a headphone that is more of a dear old friend, and not this year's model? As though, because we own "the best", we damn well better enjoy it. I say, let us enjoy what gives us pleasure, regardless of price or significance.
       Sennheiser HD598 SE is a highly competent mid-fi headphone that is both extremely comfortable and ear pleasing. It has good bass extension, lively treble, and balanced mids that lend to an open sound stage. Is the bass amazing? No. Are the higher frequencies astounding? No. Do I giggle with unrestrained glee when I listen to my old music for the first time? No. These are not magic headphones. But they are really good headphones, and I believe that a really good headphone is a great place to start in this magical quest of diminishing returns. 
      The Sennheiser HD598 SE is handsome, comes with a 3 meter Single ended 1/4" removable cable. It also comes with a shorter (1.2 Meter) single ended 1/8" cable for more portable use. I do not think that portability is where this headphones shines. It is open back and can be heard by those around you, and, you can hear them as well. So, environmental sound attenuation is poor. They do not fold or come with any way to transport them. And even though these are only 50 ohm cans, I still believe that they benefit from amplification. It is not until recently that I have conscientiously amped my phones, and I found a noticeable difference in the performance and competence of these sporty cans. I liken amplification to putting premium gas in a car that deserves it, and finding that it really does run better. The bass extension is noticeable greater, the sound stage wider, the trebles twinkle just a little bit brighter, and the mids demand a focused attention.
     I know that I have written too much about a less significant can, but in so doing I hope to impart a greater hope. I almost didn't get these because they were not "important" enough, just as, long ago I almost did not get the HD590 because the HD600 was supposed to be better. Even though I brought my own reference music and seriously scrutinized them both, my head would not believe what my ears, and perhaps my soul was telling me: I just liked the HD590 better. "But shouldn't I get the HD600 if I can? Everyone is talking about it. Maybe I just have poor taste. Maybe I simply need to educate my ears." I heard myself, muttering in the high end phono boutique: "maybe I just have poor taste" I laughed out loud in the store, looked down at the phones in my hand, the HD590, and walked to the counter. That day a revolution began: I gave myself permission to "maybe just have poor taste". There really is nothing like poor taste and money, is there? Now, I try to let my ears decide, and I am at peace with the world. But I still want some HD800 S, even to just wear as a hat!
 
    As a post script I would like to point out that though this headphone has not undergone the Frankenstein-ian Modifications that some phones have suffered (HD700/800), the single ended cable attaches at the can with a 2.5mm TRRS jack, which would lend itself to balanced re-termination. 

    I bought these back in 2000 for full retail, which was a lot of money for me at the time. I got to A/B these at a hi-fi shop using my reference CD. I listened to the HD600 and the HD590. I really enjoyed the sub bass impact on the HD590. I was buying them as reference /monitoring headphones for making music with a lot of sub bass content. (It's not always cool with my neighbors to blast sub woofers) They don't have a particularly flat FR, but that is not what I was looking for. I was looking for something that could recreate or replicate my 4.1 desk system that is based on car audio which is what I make music for in the first place. (the cars that go "BOOM")
    The Sennheiser HD590 has served me well for over a decade. They are not fatiguing, and work well for long work sessions. They remain cool and comfortable, which allows me to continue working. Most importantly, I can hear my wife when she pokes her head in the door and says some completely random non sequitur that requires a considerate response or my work will be cut short So, Sennheiser has improved my quality of life. (Thank you, Senn)
    I am writing this review because in doing research for new headphones, I found that these HD590s only had two reviews. I believe that these deserve more attention than that. Also, it is rare that I can add something to Head-fi that has not already been said better.
(Thank you Head-Fi for taking me from Walkmans to Tube Amps)
    In short, if these were the only headphones in my life,  it has been a beautiful ride.

I really loves these JVC HA-FX3X iem. I have been searching for something that can hit as hard in the sub bass as my desk 4.1 system, which I did find the Sony MDR XB950 over ear and the MDR XB90EX iem, but neither had the highs for the snare and high hat. I found the JVC HA-FX201 that has a great sound signature, but it begins to distort under huge sub bass pressure. (I make bass music)
I needed these because as the world becomes more cramped, it becomes less polite to blast sub bass into the neighborhood. Now I finally have a way of blasting my music that won't bug the neighbors and accurately recreates the sound I so love, without compromise. I ordered the newer HA-FX33X that will be here soon. I hope to review those as well.  

I bought these becuse they seemed high tech and were 75% off. They were strangley not comfertable or user friendly enough for me to put more than 30 hrs on them. Two years later I just pulled them out for comapison reference, and they actually sounded pretty good. They are still fiddley, meaning, I am always aware that they are there, and the bass is meh, ok, and the treble is tiring. I have JVCs that are known for strong V and maybe harsh highs on the fx201, but they have the bass to ballance it out. These don't. I am glad that I have them, but I wouldn't recommend buying them. They are too clunky and heavy for what they give back, which is meh and ouch.