JVC FD01: A new contender for best DD IEM?

JVC FD01 quick first impressions and measurements:



These are some of the best-engineered IEMs I've ever come across: 11mm DLC dome + carbon diaphragm driver, rotatable full steel housing, three interchangeable nozzles, extremely supple / high quality OFC cable with MMCX connectors, very soft and comfy Spiral Dot Plus eartips. Downside: housings are quite heavy.


Frequency response: JVC FD01 (blue) compared to Sony EX1000 (red)



A tad more sub-bass than the EX1000, but overall bass is similarly linear, articulate, fast and well-controlled. Dead neutral mids up to 2.5kHz. Slightly too forward upper mids for my taste, but lower treble is smoother than on the EX1000 and free from sibilance. Lots of extension and air in high treble gives an open and spacious feel.

Overall signature of the FD01 is neutral, with somewhat emphasized upper mids that make them sound extremely detailed, but also a tad thinnish and brittle. Nevertheless, these are without a doubt TOTL dynamic driver IEMs, and technically on par with / if not better than the EX1000.



Three pairs of nozzles made of titanium, brass and steel, interchangeable via a sophisticated j-mount mechanism.

And here's how they measure: (titanium = grey, brass = orange, steel = blue)



Now this is somewhat puzzling, lol. To be continued...

 

Subjective impressions of the different nozzles and sound? Hopefully the SS one is fine in which case you can go with the FD02 and save some money (there's no other significant difference, correct?)

 

I concede interest, but that insane upper-upper treble spike looks like it might hit the current upper threshold of my hearing, and I'm not keen on testing sensitivity in that region. Then again, considering these are in-ear measurements I'm hoping that's an artifact.

"Brittle" in the sense that things sound thinner and less weighty than ideal? How does that work for female vocals?

 

Oh nice, watching with interest. My beater IEMs, RE-600, just shat themselves. I love the design aesthetic.

 

I'll be honest: I thought I heard a subtle difference between nozzles... before taking measurements. After measurements, and going back to A/B... well, not really any more lol.

Nevertheless, there's still a good reason to go for the FD01 over the FD02, which I'll address in my next update to the thread.

Everything above 10kHz is definitely unreliable and will also depend on individual ear canal resonances.

Yup, things sound incredibly detailed, but note-weight is a little less than it should ideally be. Female vocals sound forward, though not overly strident / shrill in my book, since it's not a narrow spike. However, I'd kindly ask you to wait for my next thread update, which will deal with this more in-depth...

 

How do you find the ergonomics? Does the cable length past the splitter allow for them to be worn over ear?

 

The FD02 and FD01 look identical aside from the cables, but one is cheaper. Any clues?

 

The 01 has the three nozzles. The 02 just has the SS built in.

 

HA-FD02
"The tone is a neutral direction, and it can be said that it is a balance-oriented sound which suppresses the glitteriness of overtones. HA - FD 01 is partly giving a weight to the glamor of the high region, a feeling of brilliance, so if it is said that straight sound without adaptation is preferred, this HA - FD 02 is preferable."

fyi as with all jvc iems, note that the second in line is usually the one that is closer to "natural". While there are less tweaks to play with, from my brief audition, it has better timbre and a less peaky treble.

https://www.phileweb.com/sp/review/article/201712/30/2895.html

 

There's ample cable length past the splitter and I always wear them over-ears. Thanks to rotatable housings, you can adjust the nozzle to match the angle of your ear canal. Routing the cable over the ear also means better weight distribution than wearing them downwards. That and the extremely soft silicone tips make them overall very comfy for me to wear, despite their considerable weight.

From what I've been gathering, there are three differences:

• FD01 have interchangeable nozzles
• FD01 have higher quality cables
• FD01 have a titanium driver case

A friend of mine had the FD02 and told me that their high range was a bit too much for him. Sadly I didn't get the chance to audition them myself, because he returned them. But ultimately his comment made me opt for the FD01, since I figured that with three interchangeable nozzles, there'd be more options than with a single fixed one.

 

Continued from post #1:

Feeling somewhere between puzzled and dismayed about the fact that all nozzles measured the same, I decided to take a closer look. And sure enough, there's no damping filter in any of them, they're all just empty cylinders with the same protecting mesh that serves no acoustic purpose:



Did JVC really think the acoustic properties of steel, brass and titanium are different enough to make these nozzles sound noticeably different? I don't know the answer to that... but realizing I was stuck with three pairs of basically identical sounding filterless nozzles, I decided to put them to good use and build some filters that really make a difference.

What followed was a few hours of wild experiments and measurements, using all kinds of things like micropore tape, foam, sorbothane and so on, plus all feasible combinations thereof. Here's a sneak peek of how this frenzy looked like on my measurement rig:



Finally I settled on what I consider a simple and elegant solution: 6mm wide strips of dried alcohol swab (the inner nozzle length is about 7mm). I cut these strips to varying lengths between 12mm and 16mm:

[Edit: Make sure to use 2-ply alcohol pads, since 1-ply pads are thicker and not suitable for DIY-filters!]



Now, building a swab filter is as easy as rolling one of these strips up like a carpet and shoving it into the empty nozzle:



After some back and forth between measuring and critical listening, I settled on this configuration:

• steel nozzle = stock, no filter (analytical: extremely detailed, but slightly thinnish / brittle)
• titanium nozzle = 13mm swab filter (reference: highly detailed with accurate note-weight)
• brass nozzle = 15mm swab filter (relaxed: nicely detailed with a touch of warmth)

And here's how they measure: (blue = stock, bright green = reference, dark green = relaxed)

 

Damn, nice work (as usual). I have been looking for a DD with reference tuning for ages. I’m going to pick these up.

 

Impressive. You're a modding machine!

Regarding the FD02, any reason to think that your friend wouldn't find the FD01s too bright too?

 

What’s the blue ring in the second photo? It’s not on the nozzle in the first photo.

 

It appears as though one side is the nozzle, the other (with the o-ring) is the thread.

 

In this case, "modding" seems like an exaggeration. These are just simple DIY-filters and the changes are easily reversible.

Oh, I'm sure he'd find the FD01 stock sound too bright! But I'm also pretty certain he'll dig the "relaxed" (and maybe also the "reference") filters. Anyway, we'll have a mini-meet soon and I'm looking forward to his 2 cents...

Exactly. Looking at the nozzles picture in the first post, you can see they have colored o-rings at the rear side. One has to insert the filters from the nozzle's rear side, because the front side is blocked by a metal mesh.

Note that due to the fixed nozzle on the FD02, this could only be done from the front side after removing the metal mesh.

 

Are the apparent 4khz peaks obvious when listening?

 

With stock filters, the 4kHz peak (plus elevated treble) has the described effect of making the sound appear hyper-detailed, but a tad thin / brittle. With the damping filters, it has no more obvious effect to my ears, when listening to music. Even with a tone generator, I find it hard to detect because it's not a narrow / sharp peak.

In general though, I'd like to emphasize that these are definitely analytical and detail-oriented IEMs rather than warm and forgiving ones. But in my book, they do what they do extremely well. I have about a dozen personal test tracks to detect flaws in IEMs, and the FD01 with "reference" filters don't show a weakness with any of them.

 

Very interesting, I had given up on these for lack of info. Did you try the AKGN5005?

 

https://www.head-fi.org/threads/akgs-new-flagship-iem-n5005.869344/page-30#post-14188981

Personally, I prefer the FD01 over the AKG N5005.