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Saturday, May 25, 2013

JVC HA-FXD60 / FXD70 / FXD80: The nanotube brothers

Disclaimer: These IEMs are owned by Dan. My apologies for being so late, my friend!
Insertion depth was right at the reference plane.


The diaphragm of JVC FXD-series IEMs is coated with a layer of carbon nanotubes, which are lighter than aluminium and twenty times stronger than steel according to the manufacturer. And the coating ultimately increases stiffness and shifts the diaphragm's natural frequency upward, resulting in a very tight control of sound.

On top of that, the top-of-the-line FXD80 is equipped with a brass cylinder and an acoustic damper made of glassfiber for increased acoustic damping.







PRO: Low distortion, extended bandwidth

CON: Interestingly, there is almost no difference between FXD60 and FXD80, in terms of electroacoustic performance. Rather, FXD60 is more tightly damped. On top of that, the rear vents only work as depressurizers only.

ON SECOND THOUGHT #1: Shallower insertion not only distribute the high frequency energy evenly here, it also extends the bandwidth slightly. It is evident that the JVC nanotubes are designed to be worn shallow.

ON SECOND THOUGHT #2: The frequency response of FXD brothers are far from the Olive-Welti target, as well as from the conventional diffuse-field reference.

8 comments:

  1. Which of the three do you feel is the best? If I would guess it would be the FXD70, but I haven't heard any.

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    1. Your guess is as good as mine. They are all equally funky, just like any other IEMs from JVC.

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    2. FXD70 seems more balanced with less bass but if you look at the CSD, bass decay is very short. so i am not sure if the bass impact is good enough. It may create a weird sensation

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  2. I'm actually a fan of the FXD80's. They are definitely not reference but they are fun and the build quality is pretty stellar for the price. However I have owned 3 pairs (don't ask) and I've found that quality control is not a particularly great for this model. I found on the first pair I got no driver flex, but the following two pairs flex quite badly. The distortion figures you have published here seem to suggest some bad channel matching? Sonove sound similar kinds of mismatches http://sonove.angry.jp/jvckenwood_HAFXD80.html

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    Replies
    1. Oh 3 pairs of FXD80! It must've been a love&hate situation LOL The ones I measured were not too off, but I have to agree; JVC's got some QC issues going on.

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  3. 산미천님, 70은 60과 저역에서 특히 차이가 나는데 모델들 보셨을 때 그 차이가 어디서 오는거라 예측하셨는지요? 또 직접 들어보셨을 때 70 모델과 60 모델의 소리 중 어느것이 자연스러우셨나요? 본문에 적으셨을지 모르는 내용이나 영어가 짧아서..^^;

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    Replies
    1. 개인적으로는 셋 중에선 60이 제일 나은 것 같습니다. 그리고 저역의 차이는 아무래도 후방 벤트 구조에서 기인하는 것이겠지요. 품질 면에선 세 제품이 전혀 차이가 없는 것 같네요. ㅡ_ㅡ

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  4. 아하..;; 출시가도 크게 차이나진 않던데, 60이 만듦새에서도 뒤지지 않는 모양이네요^^; 감사합니다

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