Click to view our Accessibility Statement or contact us with accessibility-related questions
Showing 1 of 287 reviews about:
Aug 21, 2019
Drop x JVC HA-FDX1 Dual Carbon IEM

This article is a collection of what I wrote throughout several posts and includes some edits. The original thread is here: Before we even say another word about this, we need to start here:

@james444 is always digging up random IEMs and modding them with impressive results. He posted a few before and after measurements of the mods, and before long, we purchased a JVC HA-FD01 from a Japan to send along on our loaner program. Most of the folks who heard the loaner, at least those earlier in line, should be aware that I had only implemented a quick and dirty version of the mods. The "authentic" @james444 mods were much more intricate. I think @zerodeefex can tell you guys what a pain in the ass it was for him to do it right. I hindsight, I guess I could have paid my kids (with their smaller fingers) to do the proper mod for me. Anyway, the point I wanted to make is that the proper mods result in better bass quality compared to the quick and dirty version. GENERAL SUBJECTIVE IMPRESSIONS As far as words, not much more to say that already hasn't been said by others Is this a TOTL DD candidate? Sure! Why not? What's interesting is that the highs are fast. I don't think I stated this before, but we are talking about BA fast, but without the BA timbre. And most important: no f'ckery in the highs (and this is my issue with the Sony EX1000). There's no nasty lower treble peak that every DD IEM seems to have. But you guys who already have a modded FD01 already know this. This is a legit TOTL DD for $350? Get this and flip the bird with both fingers when you walk by a goober at the next CanJam wearing bright red IEMs with a white angel silk screened on the faceplates. Sucker... And oh, BTW, I'm retiring my Andromeda (actually my kid had had them for a while now). The FD1X has worked its way into my high-end portable lineup. This will be my fourth IEM in the past decade, the others being UERM (sold), Andro (given to son), Solaris and FD1X (these latter two will be in rotation). As far as the general tonal balance:
So pretty much the Blue Filter is pretty warm without the V-Shape BS? Sounds like my type of sound on the go.
Yes, sort of. Still has some upper mid-3-4kHz emphasis, but lower and mid-treble is fine, even slightly sedated with blue. The frequency response plot below is with the blue nozzles. The most amazing thing is that every DD I've heard has issues with the lower or mid treble. This may be the first time that the highs are smooth as silk for a DD! I will discuss more on the sound (bass quality, timbre, etc.) in the measurement sections below. NOZZLES The Drop x JVC HA-FD1X comes with three different nozzles.
  • White = stock (same FR as HA-FD01)
  • Green = modeled after @zerodeefex's mod tuning
  • Blue = like green above, but just slightly pushed down more in the highs
The difference between the green and blue nozzles are not huge. I do say that I prefer to the blue. The frequency response differences between the nozzles are indicated below. The white nozzle with the stock sound is too bright and too forward in the upper mids for my taste. Note that if we are not happy with the provided green and blue nozzles, we can easily do our own mods on the white nozzle. This is why it was provided.
Here are some harmonic distortion plots. Note that the distortion pattern is very different from that of IEMs that use balanced armature drivers. We have second-order dominating over third and fourth. BA drivers have a higher third or odd-order distortions. IMO, this is often heard has a lean sound loss of texture in the bass and a "squarer" sound in the highs. These DD drivers have the same characteristics of the more typical dynamic or compression drivers that most people have in their homes or hear in movie theaters. Typically BA drivers do sound "faster" (transient response) than DD drivers. In the case, I did that that these particular DD drivers sounded faster than most other DD drivers in the bass and almost just as fast in the highs compared to BA drivers. JVC is definitely on to something with their dual carbon drivers. Finally, note that the distortion distribution of the 2nd, 3rd, and 4th orders is consistent! This is a huge deal for me because it means the sound rendering is cohesive from the lows to the highs. It doesn't sound like a cello is being rendered by three different IEMs.

BURST RESPONSE AND BASS QUALITY Do I think the bass quality on the same level at the legendary Sony EX1000's? From memory not quite. However, I no longer hear the bass quality as a possible liability as with the FD01. While not the bestest, the bass is solid and something I cannot fathom as a weakness. Texture rendition is better than the Campfire Audio DDs, but speed isn't as fast. Traditional DD sound in that sense. The Campfire Audio DDs could be said to sound like a hybrid between BA and DD tech (the distortion characteristics bare this out somewhat - another topic for discussion.) FD01 125Hz Ten Cycle Burst with Decay
Drop FDX1 125Hz Ten Cycle Burst with Decay
I saw no differences in the 50Hz 10-cycle burst, so I did not post them. However, I saw significant differences in decay behavior of the 120Hz and 500Hz bursts. 120Hz can be considered mid-bass, but 500Hz is well above the bass region and into the 2nd and 3rd harmonics of what we would consider bass. I do wonder if the 120Hz and 500Hz signals (as opposed to lower frequencies) might be more reflective of "bass quality", or specifically, bass control and articulation. If we think about it, there's no such thing as "fast" bass because bass is inherently slow. Perhaps the lack of bass control we are hearing with the JVC HA-FD01 is really the lack of dampened decay from overtones pf the bass region, which are not so slow as bass proper. (Note 500Hz burst not shown here, but see here: Burst response measurements are still experimental, but I think it would be fair to say that the behavior seen in the decays of the 10-cycle bursts for the 120Hz and 500Hz signals on the JVC HA-FD01 is not typical. I don't want to jump to conclusions because of the lack of data points (we really need more data and better analytics), but maybe this explains what @shotgunshane and I are hearing in terms of "tighter" bass on the Drop HA-FDX1 Drop x JVC definitely did something here. Looks like the answer is a little bit clearer now to the guys who have asked me on whether the Drop version should be purchased on top of the earlier JVC FD01 purchase. SUMMARY
  1. Agreeable if not ideal frequency response. Warm with a touch of upper-mids to bring out vocal overtones. Amazingly gentle highs!
  2. Great timbre: inherent warmth, natural overtones, evident textures
  3. Impactful and hefty lows.
  4. Fast but natural transient response.
  5. Highly resolving of low level information in recordings.
  6. Not cheap, but IMO priced too low. In many respects, the DROP + JVC HA-FDX1 DUAL CARBON IEM is a groundbreaking product and something that I have waited for a long time.
Feb 22, 2021
purr1nI agree with this completely. The timbre and performance unseated my happiness with the Blessing 2, a great IEM in its own right, and I was about to be very happy settling with my end-game at such a relatively low price. The qualities of this excellent DD surpass every BA combo I've heard to date (includes T800, DM8, A7, amongst other hybrids) I am gnashing my teeth about the fit. I don't see this written often, so I believe I'm a niche case. I know my right ear canal does some weird angled-upward nonsense, but usually it's not a dealbreaker for most fits, and UIEM fits are no issue. But I just can't get a secure seal/fit with these, and sometimes even angling my head removes all sound from the right side. I've tried quite a few eartips including some spinfits, and all sorts. I'd be reluctant to use foams on the regular, but they didn't fix the issue anyway. I'm getting flashbacks to the Tin T2. Not much value to this post other than to lament that they are exactly as brilliant as purr1n is outlining here. And thus my heart is broken.
Feb 22, 2021
See More Reviews
Related Products