Has anyone heard any compelling upgrades to the FDX1 without breaking the bank?
I am aware that the head-fire who came up with the modded FD01 is also owns the Unique Melody 3DT which he called a small upgrade, and the DUNU Luna, which is the big upgrade.
I have the UM 3DT and had the Luna for a few weeks for testing.
Both of them are quite different from the FDX1 IMO.
It's been a long time since I had the Luna, but the dynamics and energy of that IEM were very impressive. Tonality was a mixed bag IMO, with a mid bass hump and drop off in the sub bass, paired with a pretty aggressive upper midrange. But mighty exciting, so much so that I even played with the thought of buying them. But in the end they were way too expensive for me. (Wondering how the Luna would sound with the CHORD Hugo 2 which I did not have at the time...)
The UM3DT is also a more (upper) midrange forward IEM, which can be a curse and a blessing.
In comparison to the 3DT the FDX1 with medium filter sounds dark and very punchy, but also somewhat lacking in the treble. Treble is there, but it's more in the background.
What I like about the 3DT is that it has good low bass rumble but a leaner upper bass, which makes it sound "cleaner" than the FDX1.
But I am not sure if it's necessarily better than the FDX1, I'd rather say different, and overall, personally I prefer the FDX1.
Short version:
Dunu Luna is an upgrade, but different tuning
UM 3DT might be more of a side grade
FDX1 is still a great IEM at the price point