IT03 upgrade
Mar 22, 2020 at 8:12 PM Thread Starter Post #1 of 10


100+ Head-Fier
Nov 7, 2014
Hi all,

I've been on a fruitless endeavor to replace my it03. I lost my pair a couple weeks ago and since have tried the JVC HA FX1 (worst iem purchase I've made) and the ISN H40. The way these two have been hyped really gave me hope but I'm starting to think I should just buy another it03.

My issues with the it03 were the ever so slight lack of note weight/lean notes, a lack of bass texture/impact (almost perfect quantity though), and I wish the stage were slightly larger. Also, the fit was pretty far off for me. Any longer than an hour made my ears ache.

Can I get an upgrade for under 300? I have considered the Z5 but it's hard to find used and they seem to be ridiculous to take on the go. FH5 seems to have a small stage, which I can't stand. Any suggestions would be helpful!
Mar 26, 2020 at 5:02 PM Post #3 of 10
Are you sure that your FDX1 were OK? There have been several reports of faulty units, my set was one of them.
But I guess you may still not like their tonality, coming from the IT03.

In any case - the more you tell about what you liked about the IT03 and didn't like about the FDX1 and H40 the better chance we actually get an idea what you are looking for.

Maybe take a look at the Sony XBA-N3.
Mar 26, 2020 at 5:10 PM Post #4 of 10
Perhaps the fdx1 was faulty. The sibilance was out of this world and bass was simply anemic. The treble also had a very metallic quality.

The H40 has very flabby bass to my ears. It covers the mids and highs. The mids and highs are very recessed and so seem lifeless. The stage is amazing but gets so confusing/incoherent so easily.

I like the energy in the upper mid of the it03. The accurate imaging was one of my favorite aspects. The bass was not all that textured but was otherwise well articulated. I like the subbass boost, but it just didn't have that slam I like. The highs were almost perfect. Articulate but never sibilant, detailed but not treble monsters.
The note weight of it03 was a little light for me. I'd like the Soundstage to be a bit wider/more holographic. Again, the slam was missing in the bass. Bass quantity was perfect.
Mar 26, 2020 at 7:41 PM Post #5 of 10
Reg. FDX1 - sounds like a defect. Mine had the same issue and I measured them lacking about 5-10dB bass compared to where they should be.

Your description of the IT03 sounds like you are looking for an IEM with strong bass, slightly warmer mids and energetic highs.
I always check for Crinacle's take on IEMs and that has served me well to get a feeling of what to expect.

I think you need a DD or hybrid IEM with boosted bass and some sparkle in the highs.
I really liked the XBA-N3 when I heard it and it would fit, except that maybe you'd like a bit more aggressive treble. The N3 are quite smooth from what I remember.

FIIO FH5 might fit your bill too.
But again I feel like you really want to have a bass head IEM?

Generally, try to give your brain some time to adapt, it really takes a little time to adjust, even if a new IEM is in a higher class.
Mar 26, 2020 at 7:46 PM Post #6 of 10
Did you repurchase the fdx1 and find it more to your liking?

The thing is that I found the it03 to be, on whole, more neutral than not. Tonality wise, yes, I think I prefer a slight tilt towards warmth but I don't think the it03 is a bass head IEM and it had the perfect quantity bass, just not the perfect quality. What WAS there on the fdx1 was amazing in terms of slam.

Thank you so much!
Mar 26, 2020 at 8:22 PM Post #7 of 10
Yes, I decided to take another chance and get the FDX1 replaced, however due to the current gloabel travel situation it is stuck with a friend in the US and it will take time to get them. But I already have the JVC FD02 which is the same without interchangeable nozzle and I modded it myself. And I love it. That's why I wanted to get the FDX1 to compare and to have a second pair with the benefit of easy change of tuning.

Although Crincale calls it neutral I find it to be moderately boosted in sub bass and upper mids, but the special thing about them is that I really enjoy them with pretty mucn any music. I have a collection of IEMs (see signature) which are more expensive, but the FD02 is still my most used one. It has a very realistic timbre, a tastefully boosted low bass and that smooth quality. Needs the mod and a cable upgrade though.

Ok, I thought you were referring to the bass quantity of the IT03...
That changes the considerations a bit. FDX1 with the stronger damping should actually have been an option, but would maybe still need some brain burn in.

If a smoother treble sounds good to you the Sony XBA N3 is still a good contender.
Sony EX800 with bass mod might be good too, but awkward fit and low isolation make it less practical. I love the EX1000 though, it is surprisingly powerful and dynamic in the bass, really top quality, but it is intense and sensitive to harsh sources or bad recordings. Even with good source and recording it is slightly fatiguing IMO. But very good and clear too.

Never heard the FH5 but could fit your needs too as stated above.
If you can test or buy used it would limit your risk!
Mar 26, 2020 at 9:03 PM Post #8 of 10
The FDX1 truly sounds like the fit for me, but dang the first experience was rough. Was the whole signature "off" to you because of the bass? And yes, I could imagine it to be about 5-10db light...
Mar 27, 2020 at 1:47 AM Post #9 of 10
Apr 12, 2020 at 1:06 AM Post #10 of 10
If you are still considering the FDX1, Amazon JP sells the FD02 with BT cable for €150. That is a crazy price, it can easily be modded with a piece of 3M Micropore tape, and the cable needs to be upgraded.
Then you have a BT neck cable for free. I bought it as a spare :)

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