I have very sadly just sent the Fir Audio kit on to
@xjaynine
All three of these IEMs are fantastic. My daily drivers is the Sony IER-M9. When I signed up for the tour I was hoping to discover some serious diminishing returns and come away feeling really good about the M9. It didn’t work out that way.
I was using a Hiby R6 2020 with them and used all my own tips (Azla Xelastic).
Build Quality/Aesthetics
Not much to say here. The build quality is excellent. I’m not a huge fan of shiny metal myself but they feel very solid and the inlays are a beautiful touch. The cables are good but unremarkable (in a good way). I didn’t use any of the included tips or accessories. Fit-wise, they were pretty good. They're not overly large. I did find the angle of the cable guide made getting a seal on one-side a tiny bit tricky. But I think that was mostly because my ear canal is slightly larger on that side. They were comfortable to wear for long periods.
Sound Quality
All three of these Fir Audio IEMs are a big upgrade over the M9. The Xenon 6 in particular absolutely blew me away. I’ve not been quite so floored since I first demo’d the Hifiman HE1000 V2 years ago. The detail retrieval is mind-blowing. This is my first experience with an IEM with an electret driver and it is amazing. The texture and micro-detailing is incredible.
All three sound more similar than different, there is a clear Fir house sound. They have big bass but they’re not what I would call dark. I guess you’d call them warm with bass emphasis. The bone conduction bass is legit, visceral and deep.
Like others on the tour, I didn’t play with the tuning modules. If I owned any of these I think I definitely would to tame the bass down a bit.
The Neon 4s adopt the house sound, big bass that can be boomy at times. Warm midrange and smooth treble. Excellent detail and resolution, a noticable step up from the M9. Similar overall tuning to the M9 but with more bass. One of the other participants described them as a more raw expression of the house sound. I'd agree with that. I think that comes from a smaller soundstage and so more intimate presentation, only relative to the other two though, they are very refined in general.
The Kyrpton 5s are very slightly the odd one out of the three. They have wider soundstage and better separation and space to the 4s so are a bit less agressive and intimate. But they are more of a V-shape tuning. They retain the big bass like the other two but have more treble presence that I found a touch hot/glary at times. They were probably my least favourite of the three.
As I’ve said,
the Xenon 6 absolutely floored me. No question my favourite of the three. The are true to the house sound, huge visceral bass, warm midrange and smooth treble. There's great detail across the spectrum but the treble especially had an incredible lightness, detail and extension.
Widest soundstage of the three. Utterly incredible detail retrieval and resolution and especially micro detail and fine textures. I keep some chesky recorded stuff for using when testing like this and sense of realism, of the space in the recording venue the Xenon 6 is able to reproduce is amazing.
What I’d call a guilty pleasure tuning, not neutral but very enjoyable. I didn’t mind the bass most of the time. I listen mostly to music that doesn't emphasise bass (indie/post rock/jazz). I listen to some dubstep and the bass was a bit much with those styles for me. I think bassheads would love it, there is a physicality to the bass that you don’t get without that bone conduction driver. The midrange is warm and smooth with incredible detail. The treble is so light, beautifully textured and well extended.
Thanks to
@Damz87 and Minidisc for making this happen.