New Head-Fier
Pros: Bass, timbre, beautiful design, soundstage, fun, bright
Cons: Can get too energetic and bright
Build- These things are built extremely well. The earpieces are very solid with no gaps or any manufacturing defects and they’re just plain beautiful to look at. Better yet, they use the popular MMCX connection without any modifications (unlike the Sony XBA-H3 where the connection is recessed) so should you choose to or need to replace the cable, there’s a huge choice of replacements. Something that I didn't notice till much later on was how clever JVC's removable cable implementation is. On both the driver unit and the cable itself, there is a kind of tape to add some friction between the driver and the cable, preventing it from swiveling loosely, a common issue Shure MMCX IEMs are known for.
The cable itself is understated and it takes a while to realize just how good of a cable it is. It’s more like a headphone cable than your usual IEM cable in that it’s thick and very straight with nearly no memory. Luckily however, it’s not stiff and resistant to bending so it hangs down very nicely, avoids tangling, and has low microphonics. It’s nice, loose, and floppy in the best way. I’m less of a fan of the jack which is a straight angle jack. Right angle jacks in my opinion are simply more versatile and considering that this is an IEM, the better option overall. It’s a nice jack though, with metal jacket that says JVC, a thick strain-relief, and a thinner section protruding beyond the metal jacket, making it easier to use with phone cases. Higher up on the cable there’s a decent y-split that says the model number, HA-FX850, and a cable slider, always a welcome addition. The only caveat I can think of build wise is that they’re very large and stick out prominently.
Comfort- For such large headphones, these are really comfortable. I can actually almost forget they’re in my ears and I don’t have to wear them over-the-ear like my Sony XBA-H3, which are really not fun to wear. The stock spiral dot tips are great, nice and soft and pliant. No complaints here and only praise, especially coming from the massive Sony.
Portability- Adding this because this bears noting. These really are not for on the go listening. For my reviews, even if I intend to only use the IEM at home or indoors, I do try them at least once on the go to see what it'd be like. I've done that with these and I have to say, if you considered these for wearing on the go, I'd look elsewhere. The problem is that these are very large and very heavy so they tend to slip out while moving. Also, the combination of angled nozzles and long, inflexible MMCX connectors means that over the ear wearing isn't really feasible nor comfortable. The drivers will push into your ear and the MMCX connector will push against your ear as well. Not only that, but these are vented at the back, making isolation pretty poor. The isolation is probably on par with the Sony's, but the Sony's can actually somewhat be worn on the go because of the over the ear design. To top it off, for some reason the cables on these is overly long. I'm an average height male, 5'10, and the cables on these is much too long. You'd probably have to be at least 4 inches taller than me for the length to be appropriate. Plus, no inline cable controls. You could fix this easily because of the MMCX connectors or by buying an extension cable with phone controls, but you run the risk of changing the sound, perhaps for the worse. So yeah, wouldn't really recommend these for on the go. For that, my preference is the Yamaha EPH-100 because of the extremely tiny drivers and light weight. Plus I just wouldn't' care as much risking/breaking $70 IEMs vs $200 ones.
Isolation- The isolation isn’t too bad considering that it’s ported at the back, but it’s decent at best. These aren’t really made for on-the-go listening though, more for private listening. Also, should you choose to wear them out, because of the large size and ported back, these are very susceptible to wind noise.
Tip choice- In my opinion and experience, these pair best with the stock JVC Spiral Dot tips. With other silicone tips, the treble tends to be more sibilant and bass more bloated. I tried these with meelectronics double and triple flanges, Yamaha EPH-100 double flanges, ultimate ears single flanges, and comply isolation foam tips. I wasn't a huge fan of putting comply foam tips on these; they really change the sound signature in what I believe to be a negative way. The sound becomes much more neutral but just loses that fun, joyful sound it has. Bass tightens up enormously while still maintaining quantity, making these hard to listen to since they're basically blasting a whole in your eardrums at higher volumes. Also, it seems to smear the treble, killing the detail. You also get this weird resonance that makes it annoying to listen to. That's my experience with these, take it as you will. Unfortunately I did purchase these used and they only came with one pair of spiral dot tips. I did not get to try the stock JVC marshmallow foam tips and have no experience with them.
Sound- The most important part of the review. After all a well-built comfortable headphone with terrible sound might as well be an ear plug right? These definitely live up to the very large hype though. They sound rich, bright, and lively in a way that’s just so fun and infectious that you start tapping your toes and smiling. These are very v-shaped with VERY prominent treble and bass, but the mids are very nice and rich as well. The bass is the best out of any IEM I’ve ever tried, it’s got quantity, detail, tightness, and depth, and it wields it with aplomb. No it's not as tight as a balanced armature, but it's thicker than any BA IEM I've ever tried. Drums and other bassy notes hit with authority and are a joy to listen to. The treble is great too; it’s pretty bright and peabut has this nice thickness from the wooden timbre that give the vocals life. The soundstage on these is also pretty massive for an IEM. Surprisingly though, it still somehow manages to sound quite intimate, a very large plus in my book. Also, despite the brightness, it's not all that fatiguing either.
After listening to these I finally understand why there’s such a devout following to “woodies”. The wooden timbre really is addictive. It just makes everything sound so much natural, rich and alive. The sound just has this delicious texture that you can’t get enough of. It’s something that’s really hard to convey and something that needs to be experienced to understand.
I will note however that these are not actually the best for modern music like EDM and pop. They still sound great, but they simply just pair better with acoustic music and indie rock, basically anything slow and melodic and/or using wooden instruments. They're just not quick enough, not compared to other sets. They also don't do well with very energetic rock due to the lack of speed and the sheer amount of bass.

Comparison- I also own the Sony XBA-H3 which retails for the same price as the JVC and competes directly with it. I did some A&B comparisons and here are my impressions. Usually conclusions should come last… but I’ll just open with it: these beat the Sony’s in just about every way.
Bass on the Sony’s is not very well done. Though it was intended to be one of the Sony’s greatest strengths, it’s really the Sony’s greatest weakness. It’s got quantity, no doubt about that. It can even match the JVC’s absolutely massive bass in that, but it’s flabby and flat in a way the JVC is not. It’s not very detailed and it really needs tightening. I want to say that it’s boomy but it’s really not. It’s just… two dimensional. It’s just a wall of sound without definition. The JVC is actually more boomy sounding but that’s because it has dimension and depth to it. The worst part is that the bass manages to drag down the rest of the sound with it by casting a shadow on the rest of the sound and obscuring detail. This is further exacerbated by the difference in sensitivity between the BA drivers and the massive dynamic driver.
Mids on the Sony are more recessed and are often overshadowed by the bass. When the bass isn’t overshadowing it though, it’s pretty pleasant to listen to. No real complaints here other than it sounds a bit thin.
Treble is the shining point of the Sony. The Sony has a specialized balanced armature driver that Sony has coined a “super-woofer” that really does a beautiful job with treble. The treble on this is just fantastic, it easily beats the JVC here. It’s delicate, detailed, and fantastically clear. Female vocals are a joy to listen to on the Sony. It’s also smoother than the JVC which can be too bright and peaky. My only complaint is that like the rest of the sound, the treble can sound somewhat thin and sterile, something endemic to BA drivers. Some people prefer this, but I really don't. It just doesn’t have the warmth and richness of the JVC and other dynamics. On the plus side, it is more detailed than the JVC, but that can be to it's detriment as well as it is far more critical of poor source material. Even 320 kbps mp3 sounds pretty poor coming out of it. It really shines with good quality FLAC, like the one's from Tidal.
Coherence is another big issue with the Sony. I don’t mean this in the usual way people do when they review multiple driver IEMs. The Sony’s don’t use a crossover circuit network so that’s not really the issue here. The issue is that the dynamic driver and dual balanced armatures don’t really mix well. The balanced armature drivers are delicate and sophisticated while the dynamic driver is just loud and crude. Just not really a good mix and not well done on Sony’s part. Also, while not hard to drive because it’s an IEM, the Sony is considerably harder to drive than the JVC because of the triple driver setup. Interestingly, the BA and dynamic drivers respond very differently to power and can cause a weird decoherence as the dynamic driver eagerly laps up power and overpowers the two BA drivers. This is even worse when trying to watch movies as you try to get the treble and mids loud enough during a quiet scene, but then the movie transitions to a bass heavy scene and you've basically manage to blow out your eardrums.
Soundstage is something the Sony and JVC manage to match each other equally on. Both have massive soundstages for IEMs, they sound almost like headphones. But the JVC somehow manages to still sound intimate while maintaining that largeness whereas the Sony can sound distant.
Overall, I’ll close in saying that the tuning on the Sony is amateurish while the JVC is masterfully done. The Sony sounds thin and boring and honestly, not really all that fun to listen to. There’s really no contest in terms of enjoyment. I’d love the treble of the Sony on the JVC but the JVC’s treble doesn’t really leave me all that wanting. I’ve heard good things about how the XBA-A3 and XBA-Z5 fixed most of the H3’s issues but they’re out of my price range right now.
EDIT- I tried the Sony with a warm source and wow is there a difference. The Sony now sounds rich, warm and smooth and fun to listen to. The bass still is not as competent as the JVC but the treble is definitely better. It's smoother and more detailed, and now has more weight and warmth. It lacks the tonality of the JVC but is still fun to listen to. However, the soundstage and detail retrieval do decrease somewhat with a warmer amp, but that's to be expected. Unfortunately, it's somewhat hard to find a good warm source for cheap nowadays as most dacs+amps have moved towards more neutral sound signatures. (For example Fiio's previous generation was known for their warm, musical sound, which the newer K generation, which I own, is known for being more neutral and detailed.) You're really going to need a warm source if you want to make these sound their best imho.
I’ll end this comparison with a small part on the physical aspect of the two IEMs. The Sony is large in every sense of the word. The massive dynamic driver and two balanced armature drivers do not make for a small housing. It has an absolutely enormous 16mm driver, the largest I can recall any IEM having. Not only that, but it’s also got memory wire earhooks which definitely do not help to minimize its footprint. It’s much more annoying to wear and much more obtrusive. You’ll never forget they’re in your ears. However, they are not all that uncomfortable once you shape the memory wire and get a good seal. The JVC still has it beat though, in both convenience and comfort.
Design-wise, the JVC utterly tramples the Sony. The JVC looks like a steampunk-esque wood and brass work of art while the Sony looks plasticky and cheap. Both have good build quality though, the Sony is very solid as is the JVC. It’s just plasticky and tacky in terms of aesthetics. I’ve praised the JVC cable but the Sony’s cable is easily its match or superior. It’s flat, doesn’t really have memory, very low microphonics (and any it does have is eliminated by the over-the-ear design), and is just a general joy to use. Plus there’s the awesome fact that Sony gives you not one but two cables in the box and one comes with android phone support and a headphone + control button. Also, the cables have right angle jacks, which is great. The only caveat is that since the cable is flat, it can twist around itself quite a bit. Also, worth noting is that the XBA-H3 also uses the same MMCX connection as the JVC, but whereas JVC uses a standard unmodified version, the Sony uses a sunken design to avoid the twisting issues MMCX traditionally has. This means that replacement cables will be hard to find for the Sony. To be fair though, Sony gives you two durable cables which should last you for the lifetime of the device.
In closing, the JVC is just a really great, really unique IEM. The wooden timbre is something I think everyone will love and it’s just great fun to listen to. For around ~$200 these are a great buy. Highly recommended.
(This review was conducted using a Fiio E10K. The Sony was tested with the stock Sony Hybrid + Foam ear tips, and the JVC with the stock Spiral Dot ear tips. I will note that these have a strange scooped nozzle design which makes fitting tips on them annoying. Strangely, because of this, the Yamaha EPH-100 tips, which basically don't fit on anything, fit perfectly on this. Also, do not pair these with a warm or bright source. You'll need a more detailed, neutral source to really get the best out of these. A bright source will make the already bright highs even brighter and a warm source will make these sound muddy and bloated.)
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Jeff Y
Jeff Y
I'm considering getting these but one question, can you give me a link to a place where you can get it for around ~$200? Amazon's price is more than 250.
i think he mean $250 = around~$200 LOLs
Jeff Y
Jeff Y
Lol I guess so. It's still a good deal at the price but at the same price Aurisonics's Rockets are also something I consider.


An expert on his own opinion.
Pros: Beautiful Construction, Removable Cables, Great Accessories, Unique Timbre (due to wooden driver)
Cons: Bulky Housing, Only Sold in Japan (limited warranty support), Bass Balance
   Having had extensive experience with the previous Wood series of JVC, FX500 and FX700, I was exited to see what the company had planned for this next iteration. They introduced FX650 to replace the FX500 and FX750 to replace the FX700, in addition to announcing the new flagship, FX850. Thanks to user James444, I was able to hear all 3 IEMs of this new series, while still having in possession an FX500. The FX850 garners the spotlight as the flagship and proves that JVC is moving in the right direction for the reasons followed.​
Accessories and Packaging
  Packaging presents the IEM quite well and comes with extensive instructions, which are all written in Japanese, which is no surprise as this IEM is somewhat exclusive to the Japanese market. FX850 comes with "spirtal dot" tips in 3 sizes, foam tips in 2 sizes, it's detachable cable, shirt clip and leather pouch. First off, JVC stepped forward and introduced new exclusive tips to come with these. While they look like generic single flanges, they have small dots inside which are suppose to effect the sound in some way, though at the moment no objective data has been shown as to exactly how they do so. The shirt clip is the best I've seen in the business as it's clip on mechanism allows it to be used with any cable at any given point, unlike any other shirt clip I've seen. Lastly, the leather pouch is not only aesthetically pleasing, it protects the IEM quite well while being practical. Never had a problem placing the IEM in the pouch, nor did I feel the IEM was insecure inside. All in all, the packaging is above average and the accessories are among the best I've had experience with, as you get the best shirt clip and pouch I've had experience with, in addition to exclusive tips. Compared to the previous flagship, you no longer get generic tips and shirt clip and the leather pouch is slightly bigger, making it easier for the user to place the IEM inside. Unfortunately though, I find the foam tips to be somewhat useless as they taint the sound of this IEM, if foam is a must, I would recommend Comply TS400 or T400. 
Build Quality 
  The FX850 is simply gorgeous and after owning over 100 IEMs,  I can safely say it's the best looking IEM I have owned to date, along with the 650 and 750.   The FX850 keeps the standards of the previous Wood series and improves upon it, as the wooden housing is even more sturdy than the previous cut of wood used in the FX500 and FX700. It has a more reddish color of wood compared to the previous series and what seems to be brass instead of aluminum used in the previous series in the back and front of the housing. But with such great looks, comes great responsibility, the downside of the construction is that it requires great care. I would avoid contact with rain, sweat and intense heat. In addition, the brass portion of the housing tends to scratch very easily, so marks on this portion seem inevitable but luckily discrete as long as it's taken care of. I would not recommend these as a sole, all-purpose IEM as there are times I avoid using it to prevent any possible damage or scuffs. The detachable cable is thick and sturdy and the connection is very secure, never did I have any connection issues. I had a generic mmcx cable intended for UE/Westone/Shure IEMs and it didn't quite fit as the connection as it was slightly different. Whether a certain mmcx cable fits or not depends on how it's connection is made, but folks at the FX850 thread will be glad to help. 
Comfort and Isolation
    The housing is the biggest of the 3 in the new series, so it is slightly less comfortable and bulkier. The housing is straight barrel and relatively inviting, but it's size may be troublesome for those with smaller ears. Over the ear can be done but it's impractical, I recommend a traditional fit and use of the shirt clip to avoid microphonics and relieve the weight. Isolation is average, but solid despite the vented the design. Granted, not as isolating as a fully sealed IEM, but still solid for outdoor use, in my experience, as long as a good seal is achieved. To mention, due to the housing size, some may have a problem with how much the IEM sticks out as it's very long and somewhat bulky though should be quite stable with a good seal. Isolation is about -15db if I were to guess, based on other results on IF. ER4P with the highest isolation is at -43, but I suspect more of a -20to-25db isolation in actual use.
Sound Quality
  JVC IEMs traditionally have a v-shaped house sound in my experience. Having tried the FXD Series, FXZ200, FXT90 and previous Wood series IEMs they all had similar sound signatures which focused on bass and treble. Unfortunately, I found them all to be too bass heavy and harsh in the treble. While I greatly enjoyed the FX700 and FX500 due to their one-of-a-kind timbre, they emphasized the treble and bass far too much for my taste and their audible distortion distracted from their sound. Before the release of the Wood series, JVC introduced their triple driver dynamics FXZ100 and FXZ200. With the FXZ200, JVC toned down the bass presence a wee bit and made the treble and midhighs noticeably a tad less present than previous JVCs. Unfortunately it wasn't enough for my taste and they too displayed audible distortion in their sound, though luckily a tad less bothersome than the old Wood series. Regardless, it was a step forward, so I was confident the new Wood series IEMs were going to be a step in the right direction, even if JVC had decided to not step too far from their comfort zone. Turns out, I was right...
Bass: The FX850 like all JVCs, displays an emphasis in the bass region. Objectively, it's about 8db from neutral (using Olive-Welti curve as a reference), with an emphasis in the midbass (150hz region). While I enjoyed the slam of the bass, it's bass is simply too much for my taste and would have preferred if the bass placed it's focus in the subbass. Compared to the FX700 and FX500, the bass presence is actually about the same, but the bass is much cleaner. This is because the new wood series no longer have audible distortion in the bass region, a huge flaw in the previous iteration. For my taste, I EQ down the bass about 8db in the midbass region, but choose to keep most of the subbass to maintain the slam. I will say that the bass is the biggest flaw of this IEM because the midbass is a bit too elevated in relation to it's subbass and even with proper EQ it can sound less clean and powerful than say, the bass of the Sony MDR-EX1000. 
Midrange: The midrange was said to be recessed in the previous Wood series as is the case of all JVCs IEMs. In this new series, I can safely say, it's the most midrange I've heard in a JVC, but there is still work to be done. The emphasis in the bass and treble is still there, giving the backseat to the midrange, luckily the treble has been tone down much more, allowing the midrange to shine much more than before. What makes the midrange special however is the timbre voiced by the wooden driver. Once EQed, the midrange shines in both tonality and timbre, in it's own unique way unlike other IEMs.
Treble: This is where I found the most improvement in these new JVC Wood IEMs. The treble is much tamer than before as you no longer get a very harsh metallic tinge previously present in the FX700/FX500. The FX850 however is still somewhat a bit bright on top, specially in the 5k region, but I no longer have to use heavy EQ to tame it. Tips that I found even out the treble quite well are the Meelectronics M-Duo triflanges. Treble extension could be a bit better, but overall pretty solid with no early roll off. 
  The soundstage of the IEM is above average and bandwidth is solid at both ends. What makes this IEM stand out however, is it's unique timbre. No where else will you hear such a voice in an IEM, strings specifically sound very special with these, unlike any other IEM on the market. Even with non-acoustic sounds, the timbre shines through as you hear a very natural, unique voice throughout the listening experience. While the tonality has it's share of flaws in stock form, with the right tips and EQ, you can turn this unique sounding IEM into a fairly neutral monitor. To illustrate how I would have preferred the tonality, here is my EQ modification below, using EQ10 via iOS. 
   I recommend this EQ setting, M-Duo Triflanges with the deepest fit possible, blocking the back vent completely with masking tape and poking a needle hole. This is how I find these to sound best. 
  For 300$, I would declare this IEM as a fairly solid value, though the FX650 and FX750 deliver more value in terms of sound quality. In the current state, where some IEMs are priced in the 1000$ mark with no outstanding innovations to warrant their price, the FX850 is doing pretty well for an IEM with such a unique sound. No generic BA drivers, no plastic diaphragms nor gimmicky hybrid designs are used here, just a simple dynamic with a truly unique diaphragm. While I'm generally not a fan of JVC for the use of a heavily v-shaped sound in their line-up, the Wood series provides something that is unlike anything out there in the market due it's timbre with solid performance to back it up. I will state however that I find the sound of the FX750 to be slightly better. While the treble is slightly peakier than the FX850, the FX750 has slightly more forward mids and cleaner bass response. Both of are slightly better than the FX650, but the gap between the FX750 and FX850 is smaller. Of course, what the FX850 has, which gives it much more value, is the option of a removable cable, which increases it's longevity tenfold. 
I would like to thank user James444 for the loan and Head-fi for allowing me to make such great friends!!!
notable links
Official Page
Golden Ears Measurements
Presentation Video
FX850 Head-fi Thread
Almost missed this one... great review, thanks! And nice to see someone listening to Chroma Key, such an underrated band.
Interesting observations. I would rate these earphones as among my absolute favorite. Reservations as noted above would be slightly overdone bass and a bit large size; not uncomfortable but sometime they start to work their way out of my ears. Neither were deal-breakers. Still love the sound, especially with good amplification. Clean, enjoyable and non-fatiguing.
A reader commented on the FX850 thread that one can increase insertion depth of earphones by opening the mouth slightly before insertion. That allows for a more solid fit, but the lower frequencies are also increased.
I just keep the earphones lightly inserted and the bass emphasis disappears. In reality, this seems to be a earphone designed for commuting, and the bass tuning is appropriate outdoors. No cable microphonics when walking either.
I quite liked the Senn IE800 as well, but the highly microphonic cable (which is not replaceable and seems to have some plastic defects according to the head-fi community) killed it for me. I haven't liked a BA yet, and that may be due to the "crossovers" and time alignment issues. Just too complex perhaps.
PD - I would caution against the use of digital EQ as it just sucks the life out of music. Granted, most music has been tainted in the production process, but another layer makes things worse in my experience. A separate topic well worth researching.
@SkooterI personally don't like using it with a loose fit cause you lose subbass and it leaks a bit. I think even for commuting, JVC placed too much bass here.
I like Audioforge's EQ, if used properly, it makes the IEM sound better in my experience and this is an IEM that greatly benefits from it.  


500+ Head-Fier
Pros: Non-fatiguing coherent treble, timbre of drums/wooden instruments, quick bass-transients, very-detailed rich bass, powerful subbass, dramatic sound.
Cons: Isolation is lacking due to vented design
I have never in my life heard such detailed and powerful bass in an earphone. What's even more unbelievable is that these earphones are incredibly detailed without ever sounding thin like detailed earphones and headphones tend to do in the mid and upper treble. These are the most tonally accurate earphones and headphones I've ever listened to. And the most bass-detailed headphones/earphones I've ever listened to. I can actually hear bass passages I've never instantly noticed before on headphones, but only could hear on good floor-standing speakers. The drums don't muddy up with the bass guitar, but separates wonderfully. Drums actually sound like drums now; they don't sound like a pencil rapidly tapping against a table (LOL). You can hear what it sounds like "after" the drum (reverb). I can actually hear the reverb and feel the ambience of electric guitars. The soundstage is the best I've heard in a earphone so far, besting even some mid-fi portable heaphones. This may partly be due to its vented design, making these earphones semi-open. Wood instruments sound spectacular. The timbre of wood instruments through these earphones is phenomenal. It is not a "all-in-my-mind" mental thing since I already knew they made the housing out of wood and the speaker is wood-domed(I've heard cellos, violins, etc. all my life, I know what they sound like). The Earsonics SM3's and Audeze LCD-2's sound amazing with wood instruments as well, being able to emote the essence of musical instruments; the SM3's not being made out of wood at all. But the FX850's IMO are more tonally accurate than both the LCD-2's and SM3's with more air/tonal accuracy than the SM3's and more smoothness/less grain than the LCD-2's. Lastly, these are comfortable as hell! They fit my ears perfectly with their angled nozzle design to better fit in one's ears. These are what I was looking for in a earphone or as a matter of fact headphone for a very long time. You got to try these people!
***Add-on: You will need a very quiet source/amp for these earphones as they are very sensitive and you can hear a faint hissing on sources considered quiet. This does affect the treble response quite a bit to my ears, adding a little grain to it.
Glad I gave you a peace of mind :]
I agree completely with this review. The JVCs nail the tonality of live instruments like no other headphone or earphone I have heard. I have described them to friends by also saying how drums just sound like real drums, flutes sound like real flutes, etc. And in general the bass is also more realistic than every headphone or earphone I have tried.
Yaaa heard some reedtexture yesterday...freaking real:)