Pros: Beautiful Construction, Removable Cables, Great Accessories, Unique Timbre (due to wooden driver)
Cons: Bulky Housing, Only Sold in Japan (limited warranty support)
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.
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 surprisingly very competent despite the vented the design. Granted, not as isolating as a fully sealed IEM, but still fairly above average 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.
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), 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.
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$, I would declare this IEM as a pretty good value. In the current state, where some IEMs are priced in the 1000$ 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 with solid performance to back it up. I currently don't own the FX850, but do own the FX650 due limited budget. I found that even the FX650 is better than the previous Wood series and all JVCs I have used before. The improvements from the FX650 to the FX750 to FX850 are marginal so it allows you to ease your way up the latter, while still having the best JVC has to offer at the moment. You can't go wrong with any of the 3 and those who simply want the detachable cable will have no problem paying the added premium for the FX850.
I would like to thank user James444 for the loan and Head-fi for allowing me to make such great friends.