FiR Audio Frontier Series (XE6, KR5, NE4) Introduction and Comparison.

The Next Final Frontier!

The product was loaned to me (by Musicteck) for the review purpose in exchange for my honest opinion.

Manufacturer website:  FiR Audio.  Available for sale directly or retailers like MusicTeck.


In the past, the term “basshead audiophile” would seem like an oxymoron because basshead sound tuning was geared more toward consumers who didn’t care as much about the quality of the bass or the resolution of upper frequencies.  But apparently, there were quite a few audio enthusiasts with a basshead fetish who wanted both, the quality and the quantity.  Recently, this demand was met by a number of manufacturers with releases that can put a smile on basshead audiophile faces, satisfying their need to hear and to feel the bass.  But there is so much you can do with DD and BA drivers unless you start thinking outside the box.

The first time I saw prototype pictures of Frontier series IEMs from FiR Audio, even before I read the description of the tech or sound impressions, that outside-the-box idea was staring right at me outside-the-shell with an exposed dynamic driver under the mesh grill cover on the back of the shell facing the ear.  Referred to as Kinetic bass driver, this design concept is part of the latest IEMs from FiR Audio Frontier Series, named Xenon 6 (XE6), Krypton 5 (KR5), and Neon 4 (NE4).  In this First Look overview write up, I will go over each one in details, to give you a better idea of how they sound and compare to each other.

Unboxing and Accessories.

I haven’t seen the retail packaging of Frontier Series IEMs, thus can’t comment on unboxing experience yet, though heard it will be similar between all three models, just a different cover artwork.

Based on Musicteck product page and demo sets I received, the universal version of Frontier IEMs will come with a set of 3 Atom XS interchangeable modules inside of a small holder, and leather protective case (typical round leather case), a set of silicone eartips (S/M/L), a pair of double-flange silicone eartips (M), and a pair of foam eartips (M).  There is also a cleaning tool and a hex key for 2pin replaceable socket, and should be another hex key to remove Atom XS module.  It didn’t come with my demo set, so I used 0.9mm hex key.  I’m sure retail packaging will have one included.

The custom version, which is geared more toward musicians, will have a little variation in accessories.  First of all, no eartips since it is custom.  Then, depending on the design, if you choose the option with replaceable Atom X module, you will receive a set of those instead of a smaller Atom XS.  Obviously, if you choose CIEM version with internal Atom module which is not replaceable, then none will be included.  Also, CIEM version will offer a free custom artwork and selection of other premium faceplates, and aluminum protective case.

I guess you can consider a removable cable to be part of accessories as well.  The one included with Frontier series models looks nice and feels quite durable.  It uses pure copper wires, 8-braid construction, soft and pliable, and with zero microphonics.  The cable I received had 4.4mm termination with right angle metal-housing plug, a short metal cylinder y-split and a metal rounded chin-slider, going up to 120deg 2pin connector housing along with pre-shrink earhook.  Connector housing has a clear L/R labeling on inside and the design itself is non-recessed, intended for flush mount 2pin sockets of Frontier series IEMs.  And, YES, you are finally getting standard 2pin connectors with FiR Audio IEMs!!!

Page 2 – Design.
Page 3 – Sound analysis and Conclusion.

15 thoughts on “FiR Audio Frontier Series (XE6, KR5, NE4) Introduction and Comparison.

  1. Out of these 3 FiR Audio IEMs, which one do you prefer? To me, it would be the KR5 w/ Silver Atom XS because it seems to be the least colored IEM.


    1. Quite a few people mentioned to me that since they want less colored, more transparent tuning, KR5 would be the way to go, as an upgrade to M5. I prefer XE6 because it offers something different to complement the rest of the IEMs I have and use daily, but some might find it on a warmer and a smoother side of their preference.

      Liked by 1 person

  2. Hi!!
    The Tool to change the Atom XS modules doesn’t came with the original package.
    Because of this i can’t change the modules of my Kr5…and i can’t find the correct tool to do it…
    Can you share some Amazon link of this tool?


    1. Did you ask the retailer where you bought it from? Mine review set didn’t come with one either, so, as I mentioned in the review, I used 0.9mm hex driver. Search for it on amazon or ebay.


  3. I’ve been in the hobby for a while and own: ier z1r, u12t, kse1200, lcd i4, ie900, a8000. I’m currently pondering over these fir iems as they seem very different to the norm type of tuning. Would you consider the xenon6 as being worth a shot or would I be better off with something like the Odin?


    1. Based on iems you already have, btw, great collection!, I would suggest to get something new to complement the sound sig of others. So, look into XE6 since it will be more unique. Happy New Year!


  4. Hey, you missed out on the better sound by not getting the red modules for review.
    I tried all three (4,5,6) and pretty much agree here with impressions, but found the more balanced Kr5 to also have a very slight metalic “S” sometimes in its trebles, and didn’t sound like the others (4&6) which had a more similar tonality.
    Anyways, using the red module (sold separately on website) really elevated the neon 4, with a balance and spacious sound. You can detect detail retrieval now on par with the kr5, and, to me, is like best of both ths others now. It clearly has a bit more low level resolve than my Mest2 & indigo. This now my main IEM, a real winner for me.


    1. Yes, I love red module. But you gotta keep in mind, I had all 3 iems and reviewed it before they were announced or went on sale; they didn’t have red module at that time. Got red module for both uni and custom XE6 before it was announced as well, and absolutely loving it. Now, been using their new Radon 6 (RN6) for a few months and red module is also my favorite with those IEMs. The funny thing, RN6 was announced officially at CanJam NYC last weekend where Bogdan and Vlad unveiled it. When I was talking to them at the show, I suggested to try red module, and Vlad himself went wow. I think at the show, most of the people who tried RN6 preferred it with red module which makes the sound more expanded, more dynamic, and a lot less colored. XE6 is more about elevated bass, more low end weight, thicker lower mids. RN6, which is based on the same drivers but a different tuning, is all about transparency and accuracy which still retains the impact and the depth of the kinetic bass. They complement each other nicely!


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