First Impressions: FiR Xe6

First unboxing impressions 

Frontier Series is a premium collection of IEMs, and Xe6 sits at the very top of the family tree. As its ambitious $3,900 asking price implies, this is a serious piece of kit, and you should expect nothing less than meticulous attention to detail in everything from construction, to fit, to accessories for your money. 

Thankfully, Xe6 delivers on all fronts. The IEM itself – like the rest of the series – is available in both universal and custom format, which sets FiR apart from some other high-end manufacturers that don’t offer a custom version of their universals. 

I’ll cover the unboxing experience of the universal Xe6 in the full review, but in the meantime, I’ve made a short unboxing video for you to enjoy:

The Xe6 universal shells are beautifully machined from stainless steel, with what appears to be a gold-plated finish and a gold-flecked, dark blue inlay covered with a hardened glass or transparent resin cover. Photos don’t really do it justice; my initial impressions were rather negative based on some of the early photos I’d seen, but in person they look and feel every bit the premium, jewelry-like creations that they are. 

They’re also very comfortable in the ear. Despite the solid metal construction, the earpieces are very light, quite small, with nozzles that aren’t too thick or too long, and actually grip on to all the tips I’ve tried them with so far. 

Speaking of which, tip rolling is going to be crucial to the sound performance, so I suggest you take some time to shuffle through multiple tips – including the stock silicone and foam tips – to find the best match for your preferences. I’ve settled on Acoustune AET07 tips, which have just the right softness, stem rigidity, and midrange-forward sound profile I felt best balanced the tuning, to my ears anyway. 

First sound impressions 

Despite everything I’d read about Xe6, I had absolutely no idea what to expect from it, so if you’re in the same position, I’ll do my best to describe it to you here. 

For the record, I haven’t done any detailed A/B comparisons yet, only alternating between Sony’s WM1Z and HiBy’s RS8 DAPs, with the stock cable and silver Atom module in place. I’m also not going to reference any specific tracks in these impressions, but come back for the full review and you’ll find plenty. 


I hear Xe6 to have a warm, full, powerful sound, but I also hear it to have exceptional clarity throughout. 

Even though I’ve mainly focused on bass and the special way Xe6 delivers it so far, I’m not convinced bass is the star of this show. If anything, the natural, organic vocals and the smooth, non-fatiguing but still sparkly and detailed treble are equal contenders for the top prize here. 

Starting with bass, yes, it’s big, and when there’s lots of midbass in a track, it can get a bit much, even if everything else is coming through clearly. I’m not sure what the midbass elevation is above neutral, but its graphs suggest rather massive. Interestingly, it doesn’t always sound massive, because there’s plenty of music out there with muted midbass, in which case Xe6 isn’t going to magically infuse everything with bass notes. 

Another interesting aspect is how the sub-bass relates to the elevated midbass. Truth be told, if there’s equal amount of sub and midbass in a track, the sub-bass is coming off second best. There’s definitely a healthy sub-bass presence, though there are other IEMs that rumble more (and more convincingly) than Xe6. That said, I feel the balance struck here works very well for the sound that Xe6 is going for, and any more rumble would likely detract from that, in my opinion. 

If there’s going to be a controversial part of the tuning, you’ll find it in the lower midrange. The midbass elevation starts to taper by 150Hz, but it’s still elevated well above neutral at 400Hz and 500Hz, to the point where instruments and chesty male vocals sound fuller and thicker than I’ve heard them before, on basically any other IEM. 

That thick sound is what takes the longest time to adjust to. And yet that’s where Xe6 pulls out its biggest party trick: despite the thickness, all the fine details start appearing like sparkling wet leaves in the rising mist. It’s not as if I needed hours of brain burn-in to hear them either; details are present – front, centre and laterally – from the get-go. 

From 2kHz to 5kHz, Xe6 measures relatively flat, but I don’t think elevation alone can explain the clarity here, because bass and lower mids are still significantly more elevated by comparison. So, the only thing I can think of is that the sound-shaping technology of the open BA drivers, along with the quality of the drivers themselves, must be responsible for this excellent performance. 

Treble, to me, is one of the surprise highlights of this IEM. It’s not particularly elevated, and even takes a massive dip beyond 8kHz before coming up for air after 12kHz. But oh, is this sweet, sweet treble – I daresay some of the sweetest, least offensive, most extended and, crucially, least fatiguing that I’ve heard. 

I can turn Xe6 up loud enough for the bass to bounce off the windows, and still not hear any harshness or sibilance. From female vocal overtones to strings, cymbals, bells and chimes, everything in the upper frequency region is rendered to near perfection for my tastes. 

Overall, I hear Xe6 with a gently inversed-J tonality, even though it can creep closer to an L-shaped tuning with some bass-heavy music. It’s definitely a warm sounding IEM, though I wouldn’t call it dark, and despite its sparkly nature up top, it’s not bright either. Pigeonhole this IEM at your peril.  


If tonality is a bit of a conundrum, technically Xe6 is anything but. This is one of the most technically accomplished IEMs I’ve had the pleasure of hearing. 

It all starts with a big, punchy, dynamic sound. If you want to understand what dynamic contrast sounds like, pop a pair of these in your ears. Everything starts and stops on a dime, and instruments and vocals have these huge swings that, when contrasted with whatever the Kinetic Bass is doing, makes them sound fully formed and life-like. 

Couple this contrast with top-tier resolution and a broad, natural, wide and deep stage, and you have the makings of life-size sound, something I always crave but rarely get from IEMs. Resolution is very good, maybe not quite to the level of the very best multi-driver hybrid IEMs or planars (that typically don’t have giant woofers inside their shells), but certainly above most IEMs below this price tier. Separation is very good too, as is imaging, though you’re not really buying Xe6 to pinpoint the exact location of a harpsicord in an orchestra.  

I’ll have to suss out the technical performance in more detail once I start comparing Xe6 to other IEMs, but for now it’s enough to say that you’re not sacrificing much technically to accommodate the very different, dynamic, and musically fun tonality of this IEM. 

Continue to closing thoughts…



Picture of Guy Lerner

Guy Lerner

An avid photographer and writer 'in real life', Guy's passion for music and technology created the perfect storm for his love of portable audio. When he's not playing with the latest and greatest head-fi gear, he prefers to spend time away from the hobby with his two (almost) grown kids and wife in the breathtaking city of Cape Town, and traveling around his native South Africa.


Leave a Reply

Your email address will not be published. Required fields are marked *

Recent posts