DISCLAIMER: FiR Audio and Project Perfection provided me with the VxV in return for my honest opinion. I am not personally affiliated with these companies in any way, nor do I receive any monetary rewards for a positive evaluation. I’d like to thank FiR Audio and Project Perfection for their kindness and support. The review is as follows.

FiR Audio is a company based in the U.S., who – over just the past couple years – have rapidly gone from in-ear accessory vendor to producing some of the most high-end monitors in the industry today. We covered their M in-ears last year and found each to have its own niche. Though, what they all had in common were exceptional build quality, superb technical performance – the M4 and M5, especially – and FiR’s clear, nicely-balanced house sound. Unfortunately, they also shared asking prices exceeding $1000. But, that changes today. After a long, cheeky and creative marketing campaign, FiR Audio launched the VxV (or 5×5): A five-driver hybrid with all of FiR’s tech, a smooth, versatile, airy sound and an MSRP of $999.

FiR Audio VxV

  • Driver count: Four balanced-armature drivers and one dynamic driver
  • Impedance: 16Ω @ 1kHz
  • Sensitivity: N/A
  • Key feature(s) (if any): Direct Bore drivers, Tactile Bass technology, ATOM pressure release system
  • Available form factor(s): Universal aluminium IEMs
  • Price: $999
  • Website: www.firaudio.com

Packaging and Accessories

The VxV’s packaging is perhaps its least-inspiring aspect, to be honest. It’s an extremely minimalistic cardboard box with a VxV graphic printed on top. Lifting the lid open, its insides aren’t lined with foam either. So, it’s clear that the M line-up’s fantastic packaging wasn’t feasible or replicable at the VxV’s sub-$1000 price mark. Still, though, for an IEM that only just clears that line, it’d be nice to see a hair more finesse or pizzazz. Perhaps, the M series’ packaging, but on a smaller scale.

Inside the box, you’ll find the VxV and its accessories held in FiR Audio’s leather case; the same one that comes with their M3. And, beneath it, you’ll find a simple warranty card and three stickers featuring FiR’s lagomorphic mascot: Firry. While packaging stickers with earphones isn’t a novel idea, I do appreciate the effort Project Perfection went through to design the graphics, rather than just settling with the typical company logo or product name. There’s actual personality to these stickers, and it ties perfectly into the VxV’s marketing campaign as well; a cool, rewarding easter egg for fans of the brand.

The case is a well-made, black, leather case with an almost-skin-like texture to it. It’s finished with stitching all around the outside and FiR’s symbol engraved on top. I think it’s a nice accessory to offer at this price bracket. My one concern is the same one I expressed on my M series review, which is the lack of a locking mechanism. This case opens by simply pulling the lid off; holding purely by friction. It grips really securely at this moment, and I can’t get it to budge even after violently shaking it. Only time and use will tell whether that stays in the long-term. Otherwise, though, again, it’s very nicely-made.

Inside the case, you’ll find an identical layout to what was shown on my M line-up review. The bottom half is occupied by foam with cut-outs made to hold the VxV’s cleaning tool and its assortment of tips. This IEM’s tip selection are as follows:

3 x single-flange silicone tips – small, medium, large
1 x bi-flange silicone tips – large
1 x foam tips – large

As I said on the aforementioned review, I’m a huge fan of this system, as it allows you to carry all of these accessories at once. The foam prevents them from moving as well. And, unlike the M3, M4 and M5, the VxV doesn’t come pre-attached with another set of foam tips, so you won’t have the spacing or sizing problem I described on that review. Again, though, I must note the absence of a microfibre cloth and a cable tie (apart from a plain, factory twist tie) here. Even at an MSRP of $999, I’d want to find those extras present. But, ultimately, FiR have provided the basics, and in a clever layout as well.

Build and Wearing Comfort

Despite the price drop, I’m elated to see that FiR Audio and Project Perfection haven’t lessened this in-ear’s build quality one bit. Their VxV features the same aluminium chassis as the M3, M4 and M5; robust, dense, yet light at the same time. And, the same care has gone into the finishing as well. The entire shell sports a uniform, anodised finish, and it meets its faceplate with a flawless join. Again, like the M UIEMs, these shells are impeccably smooth from socket to nozzle, which, might I add, is ridged to keep tips in place too. It is this unibody look that makes FiR’s in-ears feel as premium as they do.

Aesthetically, the VxV has certainly taken on more of a prototypical look; not as refined or lavish-looking as the M3, M4 or M5. But, it’s more of an intentional design choice, because, again, the finishing on this in-ear is as top-class as ever. Both sides have been engraved with clever industrial details: The coordinates to FiR’s HQ on the left, and this VxV’s production specs on the right, including its driver config and which prototype iteration finally went to market. To my eyes, they were engraved with even better precision than the M IEMs. Then, you have the DuPont faceplates – again, prototypical in style – with gloss-black inlays and FiR and Firry logos in white. Of course, aesthetics are extremely subjective. Some may prefer a more refined, colourful look. But, again, it’s been done with cleanliness and precision, and this is all that matters to me.

Like the M in-ears before it, I find the VxV a very comfortable in-ear to wear. Again, FiR Audio and Project Perfection have come up with a very light, very compact design that sits almost-vanishingly in the ear. Its upside-down-teardrop shape’s a perfect match for my concha, and it’s remained secure whether I’m stationary, moving or head-banging wildly. If I could add anything, though, like the M in-ears, I wish there was a bit more of lip towards the top of the shell, so it can grip onto the concha more. But, that aside, FIR’s VxV have truly been sized and weighted to be a breeze to wear; very near flawless.

For its connection system, the VxV’s been equipped with MMCX connectors. As I explained on my M series coverage, this was a decision made based on consumer feedback. It’s a standard that’s easy to get cables for, which may not yet be the case for FiR’s very own RCX standard. Then, again, FiR and Project Perfection’s socket of choice ranks among the best I’ve used in balancing security and ease-of-swapping. Then, underneath the sockets, you’ll find two ports on the VxV: One for its ATOM module, and one for its dynamic driver. Lastly, we mustn’t forget the bore’s wax filter, which shields the in-ear’s internals. You don’t get spares with the VxV, though, so you’ll have to contact FiR to get them replaced if it’s ever needed.

The VxV also comes with an SPC cable called the Specimen 25. It sports a coaxial make-up, so you’ll have half the amount of wires you typically would with a stock cable. As a result, you’ll get a more compact, more lightweight product. And, the cable’s tiny Y-split complements that further. But, it’s not bereft of flair either; sporting a metallic finish and an engraved Firry logo. Its matching, ring-like chin slider comes with impressive grip as well. Then, lastly, that design is matched on its 2.5mm plug. I personally would’ve liked to see adapters included here, or even a swap system like DITA’s Awesome Plug. But, I guess it wasn’t feasible. Still, it’s a stellar cable that easily surpasses that of the M in-ears in quality and personality.

Direct Bore Drivers

As lots of you probably know, all of FiR’s in-ears have entirely tubeless driver arrays, which they claim results in the most natural reproduction of sound. It’s a concept most synonymous with Mr. Belonozhko’s previous company, 64 Audio, and one that he’s brought to his brand-new designs here. An interesting twist Bogdan’s introduced with FiR’s rendition of the tech is the use of a foam-like material packed inside the IEM shell to tune the tubeless drivers. It’s clearly not visible here on their metal-shelled universals, so you’ll have to look for one of their clear-shelled customs to see what that’ll look like.

Now, compared to the M series’ tubeless set-up, FiR have actually added another component to their VxV, and it’s called the Sound Reactor. It’s basically a 3D-printed enclosure that the low and mid drivers fire into, and it shapes their outputs acoustically. The fact that it’s 3D-printed also makes assembly easier and more consistent. Then, because of that Sound Reactor, FiR have also been able to place the VxV’s ATOM filter right beside the woofer. They claim a 30-40% increase in relieving extra pressure from the dynamic driver, which fans of pressure-relief technology will surely be pleased to hear.

Tactile Bass Technology

Tactile Bass is yet another spin on FiR’s tubeless-driver tech; this time applied to their VxV’s 6mm dynamic woofer. Unlike the M IEMs’ implementation of Tactile Bass, this diaphragm doesn’t radiate freely throughout the entire shell. Rather, it’ll fire into that Sound Reactor enclosure. But, it ultimately still outputs into a tubeless enclosure, so you should still hear a ton of the same benefits. Like the M in-ears, it’s tech that adds verve to the lows, which we’ll discuss in the Sound section.

ATOM Pressure-Release System

FiR’s ATOM pressure-relief system is something you may be familiar with if you’ve had any experience with ADEL or apex-equipped IEMs. Like those technologies, what ATOM does is absorb pressure built-up within the ear canal and vent it out to alleviate listening fatigue. FiR also claim their technology aids these in-ears sonically by delivering a wider soundstage. Now, the main difference between ATOM and ADEL or apex is the size of the module. FiR’s ATOM modules are a fraction of the size. And, they’re comprised of different relief methods too. Rather than ADEL’s membranes or apex‘s foam, ATOM utilises surgical-grade tubing to relieve pressure. That tubing’s sub-millimetre diameter is what lets ATOM be as compact as it is. This VxV comes with a module that delivers 20dB of isolation and – unlike those in FiR’s CIEMs – is not swappable.


Sonically, The FiR Audio VxV fully embodies the jack of all trades. It’s an in-ear that coasts or rides with the music without imparting much colour of any kind or stomping its authority all over the track. There’s definitely a warmth rooted in the mid-bass, which imparts smokiness. But, that aside, the VxV truly just sits back and lets the music casually play out. That is what allows it to be as versatile as it is. It is as engaging with small-scale – solo – arrangements, as it is with multi-piece ensembles. But, again, as a jack of all trades, it doesn’t specialise in any genre in particular. It’s probably not the in-ear to get if you’re looking for another hue to add to your collection. But, if it’s your first high-end purchase, or if you’re looking for an easygoing, everyday piece for casual, on-the-go use, this VxV’s easygoing, unintrusive tonality will really fit the bill.

Thankfully, though, this unbiasedness never becomes dull or bland, and much of that has to do with this IEM’s technical achievements. The VxV is one of the most spacious in-ears I’ve heard in its price range. Its high-end extension hands the space structure and order, which is why it sounds more organised than a lot of its competition. Its backdrop is deep and dark too, which lends the VxV’s instruments a vividness when they leap onto the image. That is also what allows leads to pop, despite its more-relaxed high-mids and high-highs. With Nathan East’s Elevenate, for example, while the bass, again, imparts that smokiness throughout the stage, the vibraphone, snare and soft, almost-whispered vocals cut right through with ease. In resolution, it, again, impresses. It’ll obviously be fuzzier-sounding than the high-end IEMs I’ve just reviewed, but it doesn’t stop the VxV’s technique from impressing; clear, airy and lively in spite of its blasé, unscented, linear sound.


Down low, as mentioned, the FiR’s dynamic driver imparts a fullness to the midrange, as well as warmth to the stage as a whole. It doesn’t ever get too smoky or veiled, even. Again, its stage is kept nicely crisp, so you shouldn’t worry about this in-ear ever sounding too saccharine or soft. The bass has a clear, piston-like pump to it coming from its 6mm diaphragm. But, it’s never heavy-handed either, because of its relatively-relaxed sub-bass. The mid-to-upper-bass is more prominent here. So, with kick drums, for example, you’ll get the thump without having the beater dig through your chest. Perhaps, it won’t be the most ideal for the most morbid of bassheads out there. But, again, it’s all in the name of versatility. The tone of the bass is big and bold as well. On upright basses, you’ll get those warm, woody vibrations in full, with less impact on the pluck. But, ultimately, it’s, again, a rich, weighty versatile low-end that ticks most boxes without stepping on any toes.

Technically, clarity on the bass is slightly above-average to my ears. The warmth and smoke its mid-bass imparts relative to the verve and rumble of the sub-bass can mask certain textures. Kick drums rarely sound too different from one song to the next, and you likely won’t pick up on little bass fills as easily either. But, it compensates with extension and weight. Kick drums and toms have roundedness and heft, which can often get neglected in sub-$1000 IEMs. Again, they’re never heavy-handed, but they always hit with authority. And, a lot of that comes down to the low-end’s size as well. Kicks aren’t compacted or compressed into a tiny ball in the middle of the stage. Rather, the VxV’s plentiful headroom allows them to radiate and decay, so those sounds feel as large and imposing as they should. That is equally true for double-pedal work in metal, as it is for floor-tom fills in R&B; again, versatility. All in all, it’s a true crowdpleaser’s bass done really, really well.


The VxV’s midrange honors structure and integrity; ensuring instruments are full-bodied, well-formed and robust, rather than ultra-crisp, zingy or sickly-sweet. There’s an emphasis on how rounded and substantial they are, with how loudly or clearly they project being a secondary priority. That comes from a palpable 2kHz rise, which imparts those meaty, chesty notes, followed by a more-relaxed 4kHz range to dampen those brassier ones. So, when listening to horns or vocals, you won’t get that bright, nasally profile. And, you won’t get those clang-y overtones on snare or hi-hats either. It’s a bit more subdued than FIR’s M in-ears, but I personally think it benefits versatility. Whether it’s male vocals, female vocals, guitars or keys, there’ll always be body to the mids and richness to its texture, so those sounds are always as tactile as possible.

Although, as said on Presentation, that straightness does not translate to a lack of energy or bite. Again, this VxV benefits from a crisp, dark background, which gives these instruments vividness and impact. Whether it’s horn stabs on the Jacob Mann Big Band’s Hold Music or the simmering organ on Nick Jonas and the Administration’s Last Time Around, energy will always be present. The few times it may lack is with power ballads like Jennifer Hudson’s I Run or Celine Dion’s The Power of Love. It won’t deliver that operatic feel that, say, the Warbler Prelude can. But, again, it’s a trade for versatility’s sake. In separation, this VxV doesn’t quite meet the M4 or M5, because of its fuller low-mids. But, it easily matches its peers. And, it’ll best quite a few dynamically too with its eye for ebbs and flows, which’ll result in soundscapes that breath a lot better.


Up top, FiR have tuned this VxV’s treble for fine, precise, quick-sounding transients that cut and run without a trace. This isn’t a high-end that’s ever splashy, glare-y or brash. It’s one that pricks with the tip, then dips into the foreground below. Its first peak sits at about 5kHz, which gives an edge to hi-hats and cymbals. And, it’s what lends the snare drum its crack too. Unlike the M in-ears, this VxV’s low-treble peak sits just below its midrange, so you’ll get a softer, more natural touch that isn’t dominated by the transient. Listening to Pat Metheny’s Pathmaker, there’s a light silkiness to the guitar, the ride cymbal and the shaker, which softens them a tad compared to what you may get on the M3 or, say, Sennheiser’s HD800. That’s then met with a peak around 8kHz, so s sounds still sound like s sounds, and t’s close with a good tick, rather than turning into a shhh… or pfff… Tonally, to me, it’s a superb midpoint between soft and sharp; nicely natural and easygoing.

Further on, the VxV shelves down its upper-treble for, again, a more natural, organic hue to its tonality. You don’t get the extra hit of air that brightens or sharpens everything up. But, at the same time, it doesn’t roll-off or fall either. It’s a well- extended top-end that maintains authority, stability and precision over its imaging and dynamics. Instruments don’t ever mush together positionally or in how they ebb and flow. And, more crucially, the highs then mesh perfectly with the mids for near-perfect cohesion across the board; better than FiR’s M in-ears to me. Again, it’s really a controlled shelf that lays the high-treble back, but with the room it needs. When listening to a track like Mac Ayres’s Brand New, that artificial, lo-fi hiss he mixes in won’t get emphasised or made digital-sounding, for example. So, what is left is that structure and stereo spread an everyday in-ear needs, in addition to that easygoing, balanced, slightly-warmer-tilted sig that it proudly sports.

General Recommendations

The VxV is defined by its colourlessness, its balance and its technical merits whilst doing so. It’s, again, a jack of all trades with eggs in every basket. But, here are three of its attributes that I think may make it your next everyday in-ear monitor:

A versatile, easygoing, unintrusive tonality: As the title of this review implies, the VxV’s sonic palette is very much like water; clean, balanced and with little notable flavour. This leaves it largely suitable for a wide variety of genres. So, if this is your first high-end purchase, or if you’re looking for a piece that just coasts with the music, FiR’s VxV would make the ideal set.

A relaxed, lightly-warm response with clarity and air: Unlike most in-ears in the price range, the VxV’s warmth and calmness isn’t accompanied by dullness, roll-off or congestion. It’s a clean, well-organised take on warmth, owing to FiR’s myriad of proprietary technologies. So, if you want both a relaxed signature and an open, airy space, this VxV shouldn’t disappoint.

Pressure-relief and a dynamically-driven woofer at just under $1000: Another trait that mustn’t be forgotten is the value you get with the VxV. It’s a hybrid monitor with the imaging and vividness that comes with tubeless tech, along with the long-lasting punch of the ATOM filter. That ought to be considered if you’re deliberating this VxV as your next everyday in-ear.

Obviously, then, as a jack, it will have its shortcomings in certain genres or towards certain preferences. It’s an in-ear that inherently goes against colour. So, if you’re looking for any of the three traits below, it’s probably best to look elsewhere:

High doses of sub-bass rumble: Though this VxV’s bottom-end is characteristically DD-driven, it was also tuned with a bias towards its mid-bass, rather than the sub-bass. Its delivery, while punchy, doesn’t dig, and it isn’t ever heavy-handed. So, if you’re one to crave tons of rumble or verve to your lows, one of FiR’s M earphones would probably make a better buy.

A more-coloured, more-alluring, almost-rose-tinted midrange: As described above, the VxV’s midrange is stellar in structure, solidity and weight, but it isn’t the best at sounding expressive, euphonic or immense, especially with material like power ballads. So, if that is more your drift, an earphone with a livelier, gutsier midrange like FiR’s M4 may be the stronger pick.

Flagship-levels of explosiveness or dynamism: This VxV, though more dynamic and resolving than most I’ve heard in its tier, doesn’t quite match the M4 or M5 in excitement or scale. It doesn’t open up or punch quite as much as its pricier siblings can, so you might want to save up a bit longer if this explosiveness and headroom is something you’re really, really after.

Select Comparisons

FiR Audio M3 ($1199)

Compared to FiR’s very own M3, the VxV doesn’t come off as crisp, tight or transient-heavy. It has more meat to its bones – a warmer glow emanating from instruments – that results in it coming across more natural or realistic. Most of it stems from how FiR have differed their midranges. The VxV’s upper-midrange isn’t as bright or vibrant as this M3’s, and its low-midrange is nowhere near as relaxed or withdrawn either. With vocals – whether male or female – this means you’ll hear more of those chestier, wetter-sounding overtones. Whereas, the M3’s rendition tends to be throatier and thinner. Down low, the VxV has the more subtle sub-bass as well. The bass line on Kendrick Lamar’s Alright rumbles more powerfully on the M3. This’s mirrored up top, with the M3’s sharper, crisper and brighter upper-treble fuelling its transient-driven tone.

Technically, to me, the VxV comes off more capable. Its more-relaxed transients sit evenly with the rest of the ensemble, which creates a tidier spread of instruments and more organised imaging. On Test Drive from John Powell’s How To Train Your Dragon score, through the M3, the higher-pitched bagpipes and violins distract from the violas and cellos bellowing below. It lessens the drama from the back-and-forth between the two, while the VxV portrays that more accurately. This M3 also has weaker dynamic range compared to its sibling, which results in a sense of compression that’s especially felt on flowing, orchestral arrangements like these that rely on crescendos and diminuendos. You won’t hear as powerful of a lift as the piece reaches its climax. And, it’s similarly less-equipped in conveying the gentleness of brush work in jazzier arrangements, for example. So, in terms of technique and spatial performance, I have to hand the VxV the victory there.

itsfit Lab Fusion ($950)

What separates the VxV and the Fusion is similar to what separates it and the M3, but to a lesser extent. Like the M3, the Fusion is a slightly-leaner, more vibrant-sounding IEM with less low-mid heft and more upper-mid zing. But, it does sport a good amount of wetness and warmth to its mids too, so it doesn’t come across as crisp or transient-driven. You can say the Fusion sits between the M3 and VxV, leaning a bit more towards the latter. Now, the VxV’s advantage over the Fusion is, again, its dynamic range. Instruments cut through the background cleaner, and they pop more vividly too. In addition, you also get cleaner separation between notes on this VxV, so you get to see more of the black background below. Apart from this and that discrepancy in their midranges, I don’t really hear much to separate what the VxV and the Fusion each have to offer. Both are great everyday monitors. It’ll simply depend on whether you want a cleaner, more vibrant tone or a more linear, subdued one, keeping in mind that the latter will lend stronger dynamics, and more vivid instruments too.

MMR Gáe Bolg ($1199)

MMR’s Gáe Bolg is an IEM that shares a lot of the VxV’s sensibilities; a richer shade of neutrality with laid-backed-ness as a priority over clarity or transient attack. The difference is that the Gáe Bolg approaches it with this fuller, more intimate and concentrated-sounding midrange. Listening to Mark Lettieri’s Seuss Pants, there’s a lot more butteriness and oomph to the organ and the guitars, because of an accentuated centre-midrange. And, there’s more saturation and smack to its snare drum too. The VxV’s presentation is more relaxed or tight by comparison. It has this more studio-like sound, which encourages separation and control. Whereas, the Gáe Bolg’s bolder take is more ideal for conveying emotion and soul. It will come down to taste. In order to counteract the Gáe Bolg’s bigger midrange, it has a bit more bite to its low-treble too. It’s not as refined or clean as the VxV there, which I find more fine, precise and polite when rendering cymbals. Although, the Gáe Bolg’s splashier high-end can also add more ring and spread to ride cymbals in jazz. So, again, preference is key.

Spatially, this VxV’s tighter, more reined-in instruments and its comparatively-generous higher-treble contribute loads to its tightness and precision. Notes stay where they are. Whereas, the Gáe Bolg’s fatter, warmer images are more prone to a bit of spread. They’re closer to the listener too, so the stage overall doesn’t come across as open or roomy as the VxV’s. But, again, whether or not that’s a positive ultimately depends on preference; more ideal for intimate solo performances than big band material, for example. The stage the VxV creates is wider and taller too, which is definitely one of its strong suits. Finally, down low, the VxV’s dynamically-driven woofer will obviously deliver the more physical, rumble-heavy bass. If you like sub-bass for pop or EDM, it’ll have the edge there. But, MMR’s effort has given their Gáe Bolg the clearer, more melodic-sounding bottom-end. Its mid-bass has more personality and clarity to it. Like the ride cymbals I talked about for its high-end, acoustic basses sing more on the Gáe Bolg as well. So, once again, it’ll come down to your preferences here.


The FiR Audio VxV is an easygoing, unassuming and daintily-balanced monitor that fully captures the everyday carry. It’s a jack of all trades that coasts through music with clarity, refinement and the lightest whiff of warmth. And, it complements that with some of the best imaging, dynamics and end-to-end extension I’ve heard in its price level. Now, will it go above-and-beyond to deliver skull-rattling lows, expressive, emotive mids or blindingly-airy highs? No, it’s far too measured and square for that. But, when it comes to nailing the essentials – a gutsy, driven bass, clear, robust, well-textured vocals and an open, articulate, silky treble – this VxV serves it all. So, as long as you can overlook its frugal packaging and appreciate its aesthetics, FiR Audio’s VxV is a $999 hit. With top-notch industrial design, an ergonomic form factor, savvy accessories and a custom cable to boot, it’s a vastly-versatile first-buy, or a casual, do-no-wrong sidepiece for the veteran audiophile.