EDIT: I first posted this impression of my FXT208SE on 16th February (16/2). It is June now and my impressions have changed significantly (positive) since then. Mainly my claim about the bass is outdated - the bass is bottomless and goes audibly down to 20hz. Will update soon 
Looking at this thread makes me depressed, lol. Why aren't there more people raving about these things? Granted, it isn't even on the international JVC site, and it's so far only widespread in their HQed region which is Japan, but still, these things deserve more rep.
I'm here to try to
describe the difference between all the 3 different sets, and also relative to the stuff I have in my possession, namely my main portable IEM, the
JVC FX1X (eq'ed), and my home/desktop main headphones, the
Beyer DT 880s. Note: My FX1X's are
always EQ'ed to counteract the treble peaks at 3khz and 5khz respectively, and ONLY for this reason is it EQ'ed, the rest of the frequency range remains unaltered.
Thanks to Singapore's Stereo Electronics store having imported all these new JVC sets in bulk, I managed to audition all them repeatedly before deciding to actually purchase the FXT208SE. Do give them a visit if you happen to be in Singapore.
First thing I'd like to point out is,
ALL of them sound different - yes they have the same
general signature, but the whole frequency 'scale' is tilted to either bass or treble (or balanced, in the case of FXT208SE / FXT200LTD - yes these two are the same, I'll get to that in a bit).
Second thing I'd like to point it is that
my FXT208s are still on the burn at the moment and although they've changed a lot in the first 48~72 hours, I've
heard what the
matured FXT208SE sounds like (from the store) and I
know the burn-in is far from done, so
I'll refrain on commenting on these directly until the burn-in is complete.
As for the general difference between the sets, I'll just show you generally where they stand on the 'frequency scale', in order of bass-tilted to treble-tilted:
FXT100
FXT208SE / FXT200LTD
FXT200
If you wanted to include their new woodie in (which I dislike, but some people may like it), you can insert that right before FXT200.
FXT100
The FXT100 sounded comfortably dark (like reclusive/hikikomori kind of dark, which is my kinda 'dark' really) but didn't muffle out the treble too much either. I almost wanted to go for these because, as you can tell from my portable being the FX1X, I like to have my sub-bass ripped and rugged =3. I think this was because of the lack of a bass port or something, which is something the FXT200 and FXT200LTD/FXT208SE had. Also, the materials used to make the FXT100s were different too. If your priority is sub-bass, this is the one to get.
FXT200 & FXT200LTD / FXT208SE
FXT200 has the most treble, and lacks any sort of bass-rumble (or at least one that I can hear at reasonable levels).
The FXT208SE is the most balanced, out of all 3 sets, as it sits perfectly in the middle of the FXT200 and FXT100. Its bass does not extend all the way down though, and from my own pair, with the help of SineGen, it only extends until around 25~26hz, and not below that. It also tends to 'slur' its subbass a lot so don't expect a rugged bass rumble from it.
At the moment it's not finished burning in yet and I don't want to talk about the FXT208SEs solely from my auditions of it from the store so I'll just wait until
my pair is completely done before reviewing them in detail.
Difference between the FXT200 and the FXT208SE / FXT200LTD
I was actually really surprised as to why there was sound difference between the FXT200 and the FXT208SE, since the latter is supposed to be just a special/limited-edition set. I asked the guys at Stereo whether the burn-in on either of these things were actually not finished yet, and I pointed out the reason I was asking was because the difference was HUGE - listening to the FXT200 and then listening to the FXT208SE is like listening to jazz on a radio speaker (FXT200) and then being shoved into a disco with dubstep in the background (FXT208SE).
The guys at Stereo initially said that, yes, my suspicions were spot-on, the FXT200s aren't fully burned in. That was on my first audition.
The following week I dropped by again, and asked them the same thing. I think, after I asked them about the burn-in being incomplete the first time, they all actually had a listen to both of these sets side-by-side together, and they all noticed the huge difference too because on the second time that I asked them the SAME thing, their response was "oh yeah we have no idea why they sound different, they're supposed to sound the same because they're made of the same materials, just that, like the FXZs one was aluminium (or iron or something) and the other was brass (or copper or something)." I remember hearing those triple drivers FXZs and I noticed the difference too, even though it was just aluminium vs copper/brass, the difference was there. (forgive my lack of knowledge about the brass/copper thing - I didn't bother digging up info about something I'd only heard once or twice, and 3 years back, so yeah).
Strong point for all 3 JVC FXTs
This, I believe, is the
main selling point for these sets. (It's also sufficiently present in most of their other entry IEMs, like the FX101, FX40, FX1X):
SOUNDSTAGE!
I'd even say that it beats my Beyer DT880's soundstage too, but loses on the treble side (DT880's clean treble is, imo, undefeated, not even by its own 'brothers').
Try listening to this with ANY of the 3 sets, and by the GODS do you SEE the SOUND SOAR TO THE HEAVENS AND BEYOND.
But if you think making the sound soar is its ONLY strong point of its soundstage, then I'll have you know you're dead wrong.
Soundstage
generally implies that you'll be judging audio on 3 axes, plus roughly 2~3 more things that aren't really 'axes'(plural of axis) but I'll explain below,
1. Z-axis - Front-to-back
2. X-axis - Left-to-right (overlaps with the 'plus-one' below)
3. Y-axis - Top-to-bottom
and 3 more that you've probably heard a lot of;
4. Separation
5. Layering
6. Positioning
(Sorry but I'm not going in any order from here onwards though, so bear with me)
The DT880's lose out on a few of these, but mainly the Y-axis which is responsible for making orchestral choral voices and string instruments soar to the tippy-top of the 'soundstage'.
The Beyer DT880s also loses out to the 3 JVC FXTs in terms of positioning.
Positioning by the meaning of the word alone (in audiophile context) means
where the sound is coming from, i.e how good or
how convincing the headphone/IEM is at placing these 'virtual' sources of sound around the 'soundstage', and THEN making them as tangible and realistic is possible (recall how some tracks or in-game audio effects sometimes make you look out your window when you thought you heard thunder and rain coming from outside, or when you thought someone was watching you from behind judging by their whispering/breathing and when you turned around, nobody was there). The best tracks to test for this are tracks that have instruments not just on the 3 main XYZ axes, but at the extreme ends of their diagonals as well. Tracks that make you feel like you're standing atop a tall tower overlooking the vast expanse of the world that stretches to the horizon below you.
The DT880s is able to give you a general sense of the 'soundstage', but that's
all that it can give you - a
general sense of the soundstage. You may say its frickin' wide or wider than the JVCs, but is it convincing?
Nope, at least not near ANYWHERE as much as how realistic/3D the JVCs' soundstage are, and across ALL of them at that.
Let me try to describe this. Imagine you're a bat, you 'image' the things (i.e. the
virtual sound sources) in your surroundings by echolocation - you roughly gauge how far away a 'thing' is by the amount of time it takes for a sound that you made to bounce back to you.
A good pair of headphones does that. A better one does this:
It doesn't bounce the sound back at you, it PLAYS it at you DIRECTLY from where it is at in 'soundstage space', no loss in quality or loudness (akin to lossy vs lossless audio file formats). From experience, I think this is roughly determined by how well the IEM/headphones can 'peg' or 'hook' their mid-bass/lower-ish-mids to its sky-soaring treble.
In my opinion, the mid-bass, when 'pegged' to the treble correctly, just makes the soundstage positioning THAT much more convincing to the mind, and as a result it sounds much more
realistic.
I won't comment on separation and layering, since I think that's easy enough for any of you to figure out what they imply, but generally all of the sets mentioned above are able to decently/crisply separate and 'layer', with the DT880's coming out on top in terms of layering (it
is called analytical for a reason).
All in all, I think the JVCs win in the soundstage department, even up against god-tier/high-end semi-open headphones like the Beyer DT880s.
Nothing beats being able to immerse yourself completely in chillstep soundscape XD.
Weak aspects across all 3 sets: upper-mid/lower-treble peaks
I've hinted at this above, but the treble/upper-mids on these have JVC's signature wonky treble peaks in them (centered around 3khz and 5khz), albeit much smaller than their entry-level IEMs, but still it's a dealbreaker if you put it up against things like the DT880s which is god-tier in terms of it's treble cleanliness/smoothness. You can throw anything harsh at it (DT880) and it'll try to pick everything apart piece by piece and then put it back together to ENSURE that it DOES NOT come back out like incoherent stream of background
noise, and instead comes out as a nice gentle breeze. Then there's also the long burn-in time to tame the peaks across all JVC IEMs (tames
sufficiently around 200 hours, and then
completely at around 250+ hours)
It's simply like a slap in the face with things like heavy metal music on the JVCs. I can never find myself looping tracks with any form of distortion or electric guitars (etc, you get the idea) in them because of the treble peaks, ESPECIALLY if they're not burned-in and tamed down. This kind of harshness is completely absent in the DT880s.
You might've heard people claiming the contrary; that the DT880s are the ones that has peaky, strong treble, but that's just because of the 'peak' at around 8khz ~ 10khz (this region actually helps instruments soar in the Y-axis as I've mentioned above, AND also
partially helps 'separation' - you can try playing around with this region with an EQ on a generally flat sounding headphone like the Audio Technica M50s and you'll see what I mean). There are also peaks in the ~16khz region which rise quite significantly when paired with an overly strong amp, so there's that too. The DT880's are NOT harsh, it's frickin' clinical in terms of its treble cleanliness up to the 10khz range, after which it gets wonky depending on your amp.
... wow it's gotten this frickin' long already, guess I'll be stopping here then.
Thus far I've only (mainly) described the bass/treble emphasis across the 3 sets and the strong soundstage of all of them against my DT880, but then I've already said SO MUCH so I'll stop here since it's already past midnight at the moment I'm typing this. If you guys want more I can come back another time
). Also found a review where the reviewer think that it's on par with CKR9 but with better dynamic and lesser soundstage (and half the price!). It's also quite power hungry where his Vivo X5max (iirc it has 9018K2M and a rudimentary headamp) can't drive it well but found it "hi-fi" sounding with a Fiio X5 which match with alorora's finding. http://pie.pconline.com.cn/599/5993207.html (in Chinese, but it's quite readable with google and/or bing translate).
