Well, it’s been an absolute pleasure to have the opportunity to experience FiR Audio’s Frontier series IEMs these last 3 weeks. Many thanks to FiR Audio and Minidisc Australia for providing the tour kit, and to
@Damz87 for organising the tour. I’ve learned quite a lot about these IEMs, my existing collection and gear, and gained a better understanding of my preferences.
Music library is something I think is important with any impressions or review. I listen to a fairly broad range of genres, but usually of the more indie/alternative, and darker sides of rock, folk, EDM, hip-hop, and rap. I put together a playlist to capture a range of some of my faves, and added a few more during my time with the FiR’s:
Packaging etc.
As this is a tour kit, I didn’t get to unbox these as you would if you purchased them yourself, but you can find this in reviews and videos elsewhere. The kit included a hockey-puck style case for each IEM that is very similar to their 64 Audio cousins. The case has a handy section in the bottom where you can store the ATOM XS modules, cleaning and ATOM tools, as well as a selection of tips.
One thing that is a minor disappointment here is that while the case looks very similar to what you get with 64 Audio universals, the faux-leather does not feel as premium and the stitching is not as well finished. Yes this is of very little actual consequence, but for the price of these IEMs I was expecting something at least on par with what I got with my U6t.
Anyway, the tour kit included a 4.4mm balanced cable with each IEM, and a single 3.5mm single-ended cable to use if needed. I’m not really into cables, but I think the stock cable is more than adequate, it is nice and soft, doesn’t get tangled and works just fine. The tips included are also quite good, the tour kit included soft silicon in 3 sizes with each IEM, a pair of soft double-flanged silicon, and a wide selection of foams.
I was a little nervous to change the ATOM XS modules, as the kit included a specific warning about how to use the micro-tool to remove and insert them, and they are very very small. These are not my own IEMs, so I decided not to bother with this, and I believe they only change by +/- 1 or 2db either way. While similar in concept to 64Audio’s APEX modules, the execution of ATOM XS is just a little more cumbersome. The ATOM X that you can get with the FiR customs seems much more like the APEX ones, and much easier to work with.
Fit, comfort & isolation
As with any new universal IEM, I experimented with a few different tips such as Final E, Azla Sedna EarFit and a few foams. The Finals kept getting stuck in my ears, and the Azla EarFit became uncomfortable after about 90 minutes or so, although I suspect a smaller size or the new EarFit Max could solve this. I settled on the stock silicon ones for the Xe6 and Ne4 (h/t to
@Damz87) and foams on the Kr5, I think those were the Campfire ones. All 3 are very comfortable for all day use, no problem at all.
As far as isolation, I was prepared for the worst based on various reviews and impressions I had read previously. However, I was pleasantly surprised to find all 3 IEMs to work fairly well in louder environments out and around, no worse really than my Andro2020 which I use on the go all the time. Yes, the open kinetic bass port does allow some additional sound to reach your ears, for example if someone is speaking near you, you can make out what they are saying pretty clearly. But, I think the *huge* bass response from the kinetic bass drivers offsets the lack of isolation, and you can still hear your music quite well.
Sound
As all 3 of these IEMs use the kinetic bass driver and therefore share some similarities, I’ll describe that first. While I’d read plenty about the bass of these previously, and now I’ve had 3 weeks to live with them, I’m still amazed every time I hear it. Sub bass extends very deep with powerful impact coming through the kinetic drivers, this is bass that I can feel as much as hear. The standout of these though for me is the incredible mid bass warmth that manages not to swamp the higher frequencies. This, in conjunction with the lovely lower mids, creates the engagement and emotional connection to my music that I crave.
On to the Ne4 specifically, and I have to say I really like this IEM a lot. It has a relaxing, easy-going nature that I can, and did, listen to all day. The bass as I’ve mentioned is deep and powerful, the midrange feels very natural, and treble is smooth and laid-back, but with plenty of detail. Other than the bass, nothing really jumps out at you, which I think is the point of the Ne4. Later on in my time with the Ne4 I put it on the FiiO LC-BT1 lanyard and used it while out for a walk or a light jog, and while it may be overkill for a workout IEM, it does a great job of it. Compared to the Xe6, the Ne4 doesn’t extend quite as well in the treble, feeling just a tad rolled-off, stage is a little narrower and shallower, and micro details are perhaps just a bit smeared by comparison. But again, that’s what lends the Ne4 its relaxed vibe vs the more intense Xe6. Oh, and it’s just a little over half the price.
The first few listens I had with the Kr5, I was overwhelmed by its aggressive treble. It was so much that I actually found the bass wanting at times, as all I could hear was very bright treble bordering on sibilance, at least with my usual music library. Undeterred, I tried using foam tips, and switched to SE sources like the laidback Asgard3, and these changes brought the treble under control a bit better; but with the Ne4 and Xe6 around, I couldn’t see why I’d bother much with the Kr5. Finally I figured that with the treble-forward nature of the Kr5, perhaps I would try some Classical, and here is where I found the Kr5 to be a real hit. I found symphonic works, concertos in particular, to work especially well with the Kr5, notably Mozart’s Concerto for Flute & Harp, and Beethoven’s Triple Concerto; the solo instruments really pop forward above the rest of the orchestra in a way that created quite a vivid image in my mind of the musicians on stage. And when called for by the full weight of low-end strings, horns and percussion, the kinetic bass of the Kr5 did not disappoint. After this I kind of ‘get’ the Kr5 now, and going back to some of the lighter, acoustic styles in my general collection, I can appreciate what it is doing. To sum up the Kr5, on this new release from Florist it really hits the mark:
https://florist.bandcamp.com
Last, and certainly not least the Xe6. I have been absolutely mesmerised by this IEM from the first listen, it suits 80% of my music library perfectly, and actually I haven’t found much of anything that made me think I’d rather be listening with something else. Of course the sub bass on EDM & Rap tracks hits hard and deep, and as I mentioned above the mid bass and lower mids create a beautiful, warm platform for the music to sweep me away. One thing that really surprised me though is how light and delicate the Xe6 can be, for example on Adrianne Lenker’s acoustic
songs record, or beabadoobee’s recent
Beatopia. While you might assume all that bass would just gobble up and overwhelm the upper frequencies, that is not at all what I hear; rather I hear a lovely warm glow coming from the low end that creates a wonderful sense of atmosphere. I listen to music for this emotional connection, and the Xe6 consistently delivers as well or better than just about anything else I’ve heard.
Pair Ups
The tour kit included a 4.4mm balanced cable connected to each IEM, so I straightaway assumed that would be necessary to get the best out of these IEMs. But that wasn’t the case in practice, in fact I found all 3 of these IEMs incredibly easy to drive well with just the Apple dongle from my iPhone or iPad, and the Ne4 to be particularly forgiving. While on the one hand source-matching IEMs can be an enjoyable pursuit of this hobby, sometimes I get decision-angst and just can’t be bothered, so I appreciate IEMs like this that remove that from the equation.
As I mentioned above, I did source-roll the the KR5 a bit in an effort to tame it’s treble. Going balanced with the HiBy RS6 and Schiit Jotunheim2 controlled the bass nicely, but then the treble could get a bit hot depending on what I was listening to. Switching to SE relaxed the treble, but at the expense of less control of the bass. It was actually the Schiit Asgard3 that I found worked consistently best with the KR5, and the Astell & Kern SR25 sounded fine with no real issues, other than lacking a bit in dynamics compared to the others.
The Xe6 was almost as equally forgiving as the Ne4, however occasionally when using balanced from the Jotunheim2 or RS6 it could get just a little intense. Again, a switch to SE would tame this, and I found the Schiit Vali2+ tube amp to work really well; a brighter tube tightens up the bass a bit while maintaining the Xe6’s strong punch and impact.
Comparisons
The comparison I was most interested in was with the Xe6 and the Sony IER-Z1R, another IEM well renowned for it’s incredible bass. However, I came to realise that these 2 are rather more different in how they present bass. The Z1R sub-bass extension is nearly unparalleled in all of head-fi, however it does slope down rather significantly in the mid-bass and lower mids when compared to the Xe6. This is what gives the Z1R it’s huge, cathedral-like sound that paints an almost larger-than-life image in your mind. The Xe6 mid bass shelf and lower-midrange extension by comparison creates a warm soothing glow around instruments and vocals in these frequencies, and for me is where musical engagement largely comes from. That’s not to say that the Z1R is not an engaging listen, it just does it in a different way, and different ears may prefer one to the other. Me, I like ‘em both.
Another Xe6 comparison I was keen to understand is with my beloved Meze Empyrean. At first you might think this is an apples and oranges kind of thing, but I found the sound signature of these two to be remarkably similar, especially the sub-bass extension and midbass warmth. The Xe6 pulls ahead slightly with a more articulate and detailed treble, that the Empyrean can approximate with a bit of EQ. The Empyrean of course being a full-sized headphone has a much larger and even grander presence that the Xe6 nor any IEM could ever achieve. However it is a remarkable achievement that the Xe6 can at least approximate this. In the end I’m not surprised I enjoy the Xe6 so much with its uncanny resemblance to the Empy.
Conclusion
The best praise I can give these IEMs is that for the 3 weeks I had them, I felt a very strong compulsion to listen to them as often as possible. Now, I already have a 6-8+ hours a day habit, so finding more even time is/was not easy, but man did I ever want to just not stop listening. Whether the music was something familiar or something new, more often than not I found myself reaching for just a few more clicks on the volume dial.
So which one of these is best, and what should you buy? That will really depend on your priorities in the hobby, and what else you might already have in a collection. Of the 3, the Ne4 is the closest to an ‘all-rounder’, that plays nice with most sources and music libraries. The Kr5 is for those ears that can tolerate/prefer a much brighter treble, and may look for detail and presence there. And the Xe6 is/could be the ultimate basshead TOTL, depending on how exactly you like your bass.
I’m not sure where this leaves me exactly, as there is some overlap with my existing collection. But for now I’ll sign off with this:
these were very much my impressions when I listen to all of them!
