Construction: The cable on the JVC FX850 is nicely sized, flexible and lacks microphonics. It ends in a normal 3.5mm plug and is also detachable, having MMCX connectors (which Shure also uses). The FX850 has 3 front-vents and 1(?) back-vent. (Though it’s a ring vent, so I can’t see how many holes are actually there) Despite all the vents, isolation is still adequate. Isolating a little less than my Sony xb90ex but still enough to use on my daily bus commute to school at a reasonable volume (though it’s hard to hear the bass). The body of the earphone is like a piece of art, solidly built but because of its pleasing aesthetic wooden design I’d rather not let anything happen to them.
Sound: The FX850 has a large soundstage for an in-ear, bigger than a JVC HA-RX900 (a semi-open/closed headphone with a larger soundstage than most) but a little smaller than the MA900 — it also lacks the ‘sense’ of openness the MA900 has( maybe the isolation is throwing me off, the FX850 feels disconnected with the outside whereas the subtle ambiance helps the MA900 place its sound outside itself). The FX850 has a large amount of bass, though it isn’t as bass-heavy as the xb90ex. It has good low extension but is more subtle <40hz than the xb90ex — though quality, speed and texture it trumps the xb90ex in every way (as it should.) as well as the MA900. The bass emphasis eases into the midrange nicely, warming up vocals a tad too much on some songs, but sounding very life-like on songs that are neutral-to-slightly bright. The midrange is ever so slightly recessed, and on some tracks, the vocals sound a tad distant and that could just be the recording, which is another thing worth mentioning. The FX850 has a unique way making the difference in albums/songs discernible via how it was recorded/produced, it’s like each album has it’s own unique ‘voice’ or ‘signature’. When it comes to treble, the FX850 outshines all my other headphones — and that is not to say that they’re bright. Compared to the MA900, the FX850′s treble is a bit more pronounced with better extension and has a lot more clarity, though still sounding slightly below neutral. Like the MA900, the FX850 has a warm-ish sound which may be misheard as sounding slightly veiled, but is actually very resolute and natural — the FX850 taking the resolution to the next level (though the bass sometimes doesn’t let you hear all the detail it reproduces, it’s definitely there). I’m unsure about timbre, but when it comes to realism I think the MA900 still has the edge on the FX850, though the MA900 can sometimes sound dull (perhaps lacking timbre?) with some instruments. The FX850 still outdoes the MA900 with precision and is far more revealing, despite having bigger bass and a smaller soundstage.