Itsfit Fusion

About myself

I'm 38, so my hearing is possibly not the same as in my 20s. I like various music genres, mainly prog rock/metal, blues and some classical music. I'm not into rap/hiphop/EDM so I don't have a strong preference regarding excessive bass quantity.

Some background

I've purchased this item myself here on Head-Fi, it was used. I have no affiliation with the manufacturer nor was this a sponsored review of part of a loan tour.

Unboxing

Everything is packaged well, has a good selection of tips included along with cleaning tool and cloth. You also get a card signed by the team. This is very personal and a nice gesture.



Comfort and fit

The Fusion does not have a deep insertion, but it still isolates quite well. Not like a Shure or an Etymotic IEM, but still sufficient. Definitely comfortable.



Sound

I was coming from a Shure 846, so the difference was striking. So much more treble Because of this, the detail retrieval is very good. Interesingly, the bass was also better than the 846, but I guess that is because of the 7 years of difference of being announced.

As both the bass and the treble is turned up, I feel the mids are a bit laid back, so if you love vocals then this may not be the best IEM for you.

The only problem is that I find it a bit fatiguing to listen to, the emphasized treble makes it unpleasant after an hour or so.



Comparisons

As I already mentioned, I like this better than the Shure 846. I think there are options that offer similar performance with a much friendlier price tag, but at least if you buy these, you'll know that you support a small team in Vietnam who do a great job handcrafting their products.

Sources

Does not need much power, but for sound quality it is highly recommended to get a good DAP or at least a good USB dongle, like the E1DA 9038D.

Conclusion

I love this IEM, it has great technical capabilities and it is a pleasure to listen to. Unfortunately the treble is a bit over emphasized for me, but apart from that, I can highly recommend them.

Itsfit labs Fusion Review



About

ITSFIT LAB is a custom in-ear brand (CIEMs) that was originally a small lab specialized in sound & audio components research in Vietnam. They have been in re-shelling business since last 3 years and have ventured into IEM market with their first ever set of IEMs, R3 at 305$ and the flagship, Fusion at 950$. They can be ordered in both universal and custom designs. This review is about their flagship, Fusion, which is a tri-brid IEM, and is among the very first to use a magnetostatic driver. Specifications, as sourced from their website:

Configuration: 1 Magnetostatic driver for highs, 2 BAs for high-mids & mids, and 1 Electro-dynamic for lows. Frequency Response: 4Hz – 40kHz. Sensitivity: 98 dB/mW @ 1kHz. Impedance: 13.1Ω @ 1kHz. Isolation: -26dB.

Design, Build & Fit:

Fusion comes in a nice rectangular black box, which holds the IEM along with its cable, 3 pairs of ear tips, and a round metal box. Itsfit labs, even provide inscription on its lid mentioning their brand name and the buyer’s name, which is quite nice. Even nicer thing is that you can request them to write whatever you like on the lid. The stock cable, seems to be a SPC cable, encased in black plastic, feels light and nice to hold and has good build. Connectors and plug are nicely built and look classy. Connectors do have markings to differentiate right and left. IEM’s build and finish are excellent, and it has really very good shell designs to choose from. Fit and finish are excellent, has minimal protrusion. Comfortability is excellent too and can be used for long hours, being very light and made of acrylic shell. Isolation is okay in these because of the three bass vents it has on its shell, and I needed to ramp up the volume in noisy places to weed out external noises.

Sound Quality

I had used Cayin N6ii DAP with A01 module and 3.5mm Electro Accousti 7N Neotech UP-OCC Copper Cryo Litz cable on Fusion for the purpose of this review. I didn’t use Fusion in balanced, as I feel N6ii’s SE sounds more open than its balanced end.

Bass extends deep, is rich, tight, clean with superb control and has very good sub-bass rumble, not like a subwoofer but very enjoyable, foot tapping rumble. Bass impact is quite fast and has short decay.

Mids sound very natural, clear with a slight tinge of warmness and has tons of details. Mids are placed in center of the stage and very slightly recessed. Male vocals sound natural. Female vocals sound natural and more energetic.

Detail retrieval and resolution are top notch. You can hear each instrument used precisely and with utmost clarity. Instrument separation is excellent too with very good space between different instruments. Cymbals sound crisp and natural. Timbre is very natural and clear.

Sound stage is extremely wide and deep, three-dimensional, holographic stage with very precise imaging. Sound envelops you in a 3-d way and you can easily pinpoint the exact position of the instrument being played. This is easily one of the best traits of Fusion. The enormous sound stage wows you the moment you try it.

Treble is the best part here. Itsfit has utilized magnetostatic driver in the best possible way and the resultant treble has got excellent extension and sounds very open and airy. Treble is energetic, sparkly and very detailed and is not fatiguing or sibilant.

Verdict

Fusion, with its excellent sonic performance throughout the spectrum, provides itsfit labs a great platform to succeed in TOTL IEM market. With its top-notch performance, Fusion is an easy recommendation. I didn’t hear many other IEMs that fall under its price range, but with its excellent bass, very good mids, extraordinary sound stage and treble, it can stand on its own and compete very well against its competitors.

Nuclear Physics:

A review of the Itsfit Fusion IEM.


Introduction:

I would like to begin by thanking Kien at Itsfit for providing me with a Fusion IEM at a discount in exchange for my honest review

IEM details may be found on the Itsfit website:
https://itsfitlab.com/fusion/

Itsfit is a small company in Vietnam, that evolved out of a small lab specialised in audio and audio component research.

Their latest and top of their range IEM, the Fusion, is one of the new breed of ‘Tri-brid’IEM’s, which usually feature a combination of a dynamic driver, one or more balanced armature drivers and one or more electrostatic drivers, or occasionally a planar magnetic driver instead.

The Fusion follows this pattern with 1 dynamic driver for the lows and 2 BA’s for the mids and high-mids.

However, Kien at Itsfit has kicked the innovation machine into overdrive by introducing a possibly world-first magnetostatic driver in an IEM to manage the highs on this flagship product.

For those fascinated with Fusion physics (ho ho), here’s a bit more detail:

Adapted from their website: “Our Magnetostatic™ driver is a Hi-res certified driver that uses two pairs of permanent magnets symmetrically and independently moving a membrane in between.

This ultra-thin 5-layer ferromagnetic membrane with high magnetic permeability moves its entire surface without any dead points, minimising sound loss, transfer delay and distortion. There’s also no need to use high-voltage amping like Electrostatic drivers commonly employ, making your listening journey much smoother”.

Pricing at the time of writing was USD $950 which I would say places it somewhere around the beginning of TOTL range in terms of pricing.

It is available in both universal and custom options, with the universals available in (if I recall correctly) 3 different shell options.

I chose a universal, but Kien very kindly agreed to custom-make the universal shell in his ‘Koi Lake’ design, one of the many beautiful designs he has created for the custom products.

Photos:









Appearance and build:

The product came in attractive and understated black packaging, with the kind of hefty metal carrying case that’s becoming quite standard in higher-end IEMs these days. The classiness of the case is undermined somewhat by the slightly grammatically incorrect (and somewhat cheesy) inscription upon it. I’m not judging Kien’s English in any way, since my Vietnamese is currently limited to a few words

However, by way of feedback to him and those considering to buy an IEM from him, I’d suggest that any potential customers be very clear about what they want written on the case, and also on the IEMs themselves, should you be ordering a custom design (and of course that Kien sticks exactly to what they say).

I just said “I don’t want my name on the carrying case” and left it at that, so I can’t really blame Kien for wanting to let his natural exuberance express itself in the inscription process

The stock cable, of unknown material, is light and supple.

I’m personally not a fan of the glossy black plastic casing on it, especially on a flagship product, although in fairness there are plenty of other TOTL manufacturers who do the same.

If it were up to me, I’d prefer to see a silver-plated cable to further beautify the IEMs. Kien is a master craftsman and artist, so it’s more about framing the masterpiece here

However, on the plus side, connectors and plug look classy, and the connectors have a bright red part to the right hand side 2 pin connector, which was helpful when plugging them into the IEMs (the red part is hidden from view once plugged in, and the natural shape of the IEMs makes it clear which side is which).

Overall, build quality is excellent and seems robust, and no issues with the finishing or hardware were found.

I found the fit to be excellent, with minimal protrusion from my ears and a shell size similar to that of iBasso’s IT01s IEMs and shape rather similar (but slightly larger in all dimensions) to that of the EE line up of the last couple of years (excluding the Wraith and Valkyrie).


The Sound:

As ever, my preferred method of testing is to try out the product(s) in question with a selection of songs from various genres and to let that process draw out the comparative strengths and weaknesses of each product, with a tl;dr summary at the end for those who lack the time or indeed willpower to listen to my audio ramblings

I have a few tracks which I’ve only found available on MP3; the rest are FLAC or WAV in 16/44 or 24/192, with a few DSD64 tracks thrown in because basically I’m just crazy like that
For the purposes of this review, I used the iBasso DX160 and the Lotoo Paw Gold Touch DAPs.

Without any further ado, let us dive in with reckless abandon



Hanson: Change in my Life (16/44 FLAC).

This is an acapella song, featuring harmonising of the excellent voices of 3 brothers who’ve been singing and performing together for about 30 years.
Straight away, a couple of the key qualities of this IEM stood out:

A fairly large soundstage with good separation, allied with great clarity and detail.

This is a song I’m very familiar with.
This is a useful test track for testing the midrange and seeing how well the IEM can handle the 3 voices, individually and as a group.

What stood out for me here, was the top-class separation and imaging.
It was noticeably easy to pick out the separate voices as they sang together, but whilst still retaining the resonance of their harmonising.

I had the feeling like I was almost standing in the amongst them as they sang. The vocals were positioned relatively central and forward (which is indeed exactly where they are positioned on the stage in this live performance, so I have to give credit to the Fusion for its very accurate spatial imaging here!).

I hugely enjoyed the timbre here. The Fusion has an enormously engaging tinge of lushness and richness across the spectrum, and wonderfully captured the individual timbres of each voice (not to mention the intakes of breath in between lines, and the sounds from the crowd in the background).


Eurythmics – Angel (HDTracks Remastered 24/48 FLAC):

This HDTracks remaster sounds superb generally.

The sounds of the acoustic guitar fingerwork/plucking and the percussion are crisp and detailed. Every detail here is shining. So much detail and clarity, superb layering. However, then the vocals come in, and stand out even more, with purity of timbre, taking centre-stage.


The Ataris – So Long, Astoria:

This high tempo pop-rock song features crunching guitars with lots of percussion. Not a bassy mastering, but an otherwise fairly dense ‘wall of sound’ kind of song.

However, this song doesn’t have a particularly strong bass in the mastering, which actually I feel is somewhat detrimental to the track, given that it’s a loud, driving rock song.

I think the Fusion did fairly well on this track. A mixed bag.

Like most IEMs, it’s not able to add a great deal to the low end (you’re looking at something like the twin-DD EE Nemesis, or a bit of EQ’ing on your DAP in order to achieve this).

However, it was still better than most, especially in the last minute of the song, where the sound gets a bit richer and more musical (on the song itself).

The Fusion avoids the pitfall of some IEMs I’ve tried with this song, which end up sounding a bit congested. The Fusion’s separation manages to offset the rather ‘closed in’ mastering in the song, whilst retaining all the melody and energy that makes the song so great.


Farhan Saeed & Shreya Ghoshal – Thodi Der (from the Bollywood film ‘Half Girlfriend’ OST. 16/44 FLAC):

This song is gorgeous.
It’s very pure, clear, beautiful. It takes a good combo of equipment to display this to perfection without letting the highs become piercing or strident in occasional places.

It starts with a high-pitched female vocal, then a deeper, but sweet male vocal, and at times harmonises both beautifully together. Very moving.

I hear very good timbre on both; the Fusion handles both the male and female vocals very well. The vocals are infused with a tinge of richness and warmth that really makes them shine. The background music has plenty going on with a variety of different stringed instruments, and these are all presented with the high-contrast forwardness I’m coming to associate with the Fusion.



Alison Lau – Handel’s ‘Il Trionfo del Tempo e del Disenganno’ (HDTracks 26/96 FLAC):

A staggeringly tranquil and beautiful piece of opera.
The singer, Alison Lau from Hong Kong, has a terrific and versatile voice, able from line to line to sing as low as a low blow from a lowbrow lowlife, and higher than a Woodstock-era hippie who just discovered a bundle of $20's in his backpack

Interestingly, whilst the soundstage and separation of the Fusion have impressed me with other tracks, here – surprisingly – it seems good, but not great. In comparison, for example, to my Stealth Sonics U9 (a fairly neutral/reference TOTL IEM with excellent technical performance and a holographic soundstage), it doesn’t wow me as much.

There’s also, for the first time, a touch of sharpness to the highest points of the vocals. In fairness, this would trip up many IEMs and isn’t a fault in the IEM itself; it just comes down to whether you want your IEMs to be more vivid or more relaxed and forgiving. Use of different ear tips and cables could alter this aspect of the Fusion’s sound signature however.


Sidney York – ‘Dick & Jane’ (from Korean drama ‘Age of Youth’ OST, 320k MP3):

Ha, this is a bizarre song. Foot stomping percussion (literally on this recording), madcap vocals, a ukulele, whistling, and a ridiculous bassline that oscillates wildly in a way that only The Smiths could comprehend.

It should be awful, but somehow holds it together for a goofy fun ride.

The combination of all these things make for a tricky customer for any IEM, but the Fusion is totally in its element here.

Yet again, ALL of those things I just mentioned are popping out. The ukulele and its timbre really stood out to me for the first time with this song; so musical and capturing all the details of the strumming, with excellent transients and decay. The Fusion brought out the detail of all the various things going on without ever losing its sense of balance and poise, or sounding congested, which would be all too easy to do with this track.

Again, great handling of the female vocal; timbre on point, engaging and forward.



Shawn Mullins – The Gulf of Mexico (16/44 FLAC):

So, this is one of my go-to tracks for critical listening.

This is a song that sounds terrific where there is huge soundstage and separation or shimmering highs. Ideally both; it really brings out the guitar strumming When there’s both, it’s stunningly good. My iBasso IT03 and IT04 IEM’s do this superbly, as did the Stealth Sonics U9.

Here, the song sounds very good, but not terrific. The soundstage and separation on the Fusion are big enough to handle that aspect of the song requirements. Timbre again is excellent, really presenting the sound of the bongos so faithfully, as well as the physicality of the guitar strumming.

However, through critical listening with this song, I’d describe the Fusion as more energetic and vivid than shimmering. More sparkle than shimmer, and more ‘vivid’ than either of those qualities.

Again, neither good nor bad; just a matter of what your preference is.

“Just the facts, ma’am, just the facts..”



Garrett Kato – Love is an Advert (16/44 FLAC):

Discovered this guy via the soundtrack of Australian/NZ tv show ‘800 Words’.

Really love this song; just good modern singer-songwriter stuff with a solid backing band. Very uplifting song.

The song has a fairly good level of low-end presence in the bass, low drums and parts of the guitar strumming on the lower note strings.

The Fusion really handled this well due to the tuning of its low-end.

Right from the start, the Fusion impresses here with how incredibly engagingly it presents the drums and bass and guitar strumming.

Yet again it seems like every instrument and every detail are popping out simultaneously. My mind is just noticing detail after detail, joy after joy.

Again, the (male) vocal is presented very well, full of character and capturing perfectly the slight raspiness in his vocal style.

It’s a fairly intimately mastered song, and I’d describe the Fusion’s soundstage and separation in this track as being very good, but again just slightly less than that of the IEMs that perform to a world-class level in this aspect.


Dire Straits – Sultans Of Swing (DSD 64):

One of my go-to test tracks for testing (and just listening), and I know several other reviewers on here share this point of view

A terrific song, with lots of things to get analytical over; percussion, timbre, guitar fretboard wizardry etc.

So right from the beginning, we have a kind of strummy/plucked guitar riff, with another guitar solo-ing over the top.

Here again, the slight lack of shimmer doesn’t gel with this aspect of the track quite as well as other IEMs I’ve tried.

Again, at the risk of sounding like a broken record, vocals are superbly presented. Front and centre, really bringing out the unique timbre and character of Mark Knopfler’s vocals.

The energetic character of the Fusion again shines with this song, with it’s foot-tapping, head-bobbing driving rhythm.

There’s a natural shimmer in the mastering to this song I feel, especially with the strummed guitar, tizzy percussion and so forth, and even more so at the end. Whilst I have said that shimmer doesn’t seem to be a quality that’s particularly innate to the Fusion, nevertheless, it presents very faithfully what is already there in the track, and overall, it’s a very involving presentation of this track that just puts a smile on my face

The joyous twiddly guitar solo at the end is just infused with so much crispness and intensity.


Anberlin – The Art Of War:



This is an immense track. There’s so much going on in it and so many things to zone in on when listening. There’s powerful percussion and bass, a driving rhythm, synths and sound effects and over all this, great vocals, searing lyrics and simply majestic rock!

In terms of analysis of detail retrieval, on this track, around 9 seconds in, there’s a sudden sense of space opening up in the upper-central zone of the soundstage, along with a faint, almost imperceptible hum.

I don’t know much about music production, but I’m guessing this is the ‘channel’ being switched on that the bass guitar is linked up to (as indeed the bass comes in at the same spatial location a second or two later).

This small detail of the channel opening up for the bass at 9 seconds in is captured very noticeably on the Fusion.

From the start of the song, again, there’s just immense power and authority to the pulsing synthetic percussion effects and with every instrument that comes in afterwards. The impact, rumble and vibration as the strings are played on the electric bass is presented with outstanding realism and is so, so engaging.

As with every other track, all the instruments and effects are vividly standing out, but the tuning of the Fusion mean that vocals still manage to take centre stage from the moment they begin.


Billy Eilish - Bad Guy (16/44 FLAC):

Woah! Dat bass

Yeah, this is not an anaemic or neutral-reference IEM.

That bass is powerfully tuned in the song, and it’s so deep in the sub-bass on the Fusion. Then the sinister vocals come in, and again, that forwardness and immediacy in the presentation of the Fusion just makes them send shivers down my spine! Yet again, everything in the song is popping out with such vividness and energy. I should just start copying and pasting by now. Duh!


Buena Vista Social Club – Chan Chan (24/96 HDTracks FLAC):


This was the first track I actually listened to with the Fusion, using my (relatively) budget – but still very good – DX160 DAP.

I can honestly say I was astonished, fresh out of the box.

Everything was popping, engaging, rich, spacious, detailed.

There’s an instrument (some kind of bass I think) that comes in with a doubled up noise at 2 seconds into the song. The Fusion renders it with depth and authority. There’s bongos, congos and various kinds of percussion going on in the background and the Fusion captures them all with marvellous clarity, separation and imaging.

The different vocals are positioned centrally, very slightly forward and – spatially - spread out slightly to the left, right and centre; the Fusion surprised me with how well it separated out each vocal part and let me distinguish each singer clearly in a way I’ve never heard before. That’s a seriously good technical performance, and the timbre on each of the male vocals – especially the deep bass one – was top class.

There’s a light and delicate tactility to the guitars, the picking of the steel guitar and the fingerpicking of a different, acoustic guitar.

It’s that dynamic driver physicality that really adds to the realism of the timbre, and here on the Fusion it’s executed with delicacy and gracefulness.

The soundstage is wide, with good depth and height, and excellent layering. It seems to strike a very good balance between providing separation and air around the instruments and vocals and allowing a degree of intimacy in the performance.

Final mention must go to the brief trumpet solo, which comes in at 02m37s.

It’s a good test of an IEM (especially with my treble sensitivity); can it present it without being wince-inducingly sharp, but without losing faithful reproduction of timbre and the heart-aching emotion of the moment?

In the case of the Fusion, it very much walks the line on the edge of sharpness for me here, but just manages to stay on the right side of it.

The trumpet sounds great.

I should add that upon listening to this track (and indeed most other tracks) with the Lotoo Paw Gold Touch really made the Fusion shine.

It audibly scales up in quality with a TOTL source; greater clarity, detail, improved technical performance and a slight ‘opening up’ of the whole soundstage.


Summary of the sound signature:


It's probably just my personal bias, but I always feel faintly cheated and offended when I encounter a dynamic driver IEM that doesn't have walloping bass, given the ability of the DD technology to deliver a stunning, visceral, tactile low end.

It seems like an affront against nature or something; like buying a specific high-power DAP because you need the extra power to drive your headphones, only to find someone has slapped a volume cap on it


The low end I’d describe as being tuned reasonably above neutral, with a fair balance between sub-bass and mid-bass. It has the sub-bass impact and physicality of the dynamic driver that brings the life and energy into the music you play on it, along with the warmth and richness from the mid-bass and the general tuning of the IEM, which brings that quality of lushness and engagement with the music.

The mids are well balanced, and strike me as being forward if anything. Timbre is excellent, especially with vocals which always seem to take centre stage.

The treble is clear and vivid, rather than delicate and shimmering. It has good extension and a reasonable amount of air.

Detail levels are excellent. Spatial imaging and layering are similarly great. separation and soundstage are excellent too, with the caveat that there are other TOTL IEMs that just have an edge here with regards to these qualities.

There’s a lovely degree of note thickness and weight, without ever becoming cloying or muddy.

I’d have to finish this section by saying that everything on the Fusion just pops, as if the contrast and vividness have both been turned up to 11.

The experience is insanely enjoyable for me, but there’s so many details and engaging aspects grabbing my attention..


It’s enormously engaging most of the time, but I think the cumulative effect from extended listening sessions is – to employ a pugilistic analogy - a bit like trying to repel multiple attackers coming at you simultaneously from several directions



Cable swap!

I found that using the Eletech Prudence SPC cable with the Fusion was extremely rewarding. The Prudence definitely provided an increase in bass definition and impact, adding a touch of extension and air to the treble, and overall a boost to the technical performance. Generally, it gave it a slightly more balanced and even tuning overall.

It’s an interesting effect in that it doesn’t seem to compromise that vivid, hi-definition sound; if anything, the added clarity and definition enhance that quality, and yet I did feel that the occasionally overwhelming ‘all dials turned up to 11’ nature of the Fusion was alleviated with the Prudence in some strange feat of wizardry

I’m genuinely struggling slightly to say whether I can define the Fusion as TOTL or not. I think my overall feeling is that, yes, it is. It provides an experience that I haven’t really had with any other IEM, at any price point.

However, the doubts, I suspect, are in part due to the perception of what TOTL constitutes. Years of having ‘neutral-reference’ perhaps held up (in some quarters) as the model of what TOTL means is probably an influence in this.

But the Fusion does so much so very, very well (and I’m talking world-class here).

It certainly does ‘addictive enjoyment of the music’ better than plenty of other TOTL IEMs I’ve heard, and shouldn’t that be one of (if not THE) prime standard against which any IEM is judged after all?

Yes, there are IEMs which have a more holographic soundstage, or more extended and shimmering or sparkly treble. But then, thinking back, they didn’t have the same character and engagement that the Fusion brings.

There’s not much I can compare it to, because it does sound a little bit different to everything I’ve heard so far.

Of my existing IEM line-up (or those I’ve heard a lot recently), it combines the gorgeous musicality, engagement and enjoyment of the USD $499 Stealth Sonics U4, with the energy, vividness and intense fun of something like the EE Nemesis or Legend X or Valkyrie (but not quite so much bass as the first two).

I’d say Legend X and Stealth Sonics U9 have the edge in terms of technical performance (and bass impact and rumble, in the case of the Legend X).

The U4 has a similar level of musical enjoyment and engagement, but a significantly more relaxed, smooth and forgiving sound signature.

So, as ever, we come back to “it’s all about your own preferences”


Conclusion:



I can begin with the standard kind of disclaimer that, as with most good audio equipment, it’s all about one’s own sonic preferences.

This is an IEM that seems to me like it has the dials turned up to 11, all of the time. Honestly, it does get a bit fatiguing for me sometimes, but then as I’ve mentioned, I do have a known sensitivity to treble (possibly other things) and am prone to this.

This caveat aside, this IEM may – for my sensitivities – not be here for a long time, but it is very much here for a good time

It’s just amazingly enjoyable and engaging.
Stunningly vivid and with details popping out everywhere.

I’d imagine if someone from the 1980’s fell through a wormhole and ended up watching UHD TV in our present time, this might be something of the feeling they’d experience.

Just as with hi-res video, now that I’ve experienced this IEM, I can’t imagine not having it in my line-up to listen to daily.


Summary (TL; DR) :

The Fusion offers a rather unique flavour of TOTL performance (or close-to-TOTL, perhaps, depending on one’s views on such things) at a very competitive price.

It sounds to me like it has all the dials turned up to 11

It is stunningly vivid, musical and engaging across all parts of the sound spectrum, with a solid technical performance underpinning all that.

A wide soundstage, with good depth and height combine with a high standard of imaging and excellent separation.

It has an impactful and authoritative low-end, which helps to engender the lush and engaging tone that informs the mids and treble.

It responds to cable pairings and tip rolling, so there’s always scope to tweak the sound signature a bit to your preferences.

This is an IEM that really emphasises enjoyment of the music, and if that’s what you’re looking for, this is an IEM that I seriously recommend you to look into.

My background - I am a professional musician, producer and audio engineer with experience in the performing, recording and pro-audio industry. I test products on a technical and musical level and try to write reviews as simple as possible from a music fan's perspective.

Genre preferences - I majorly listen to rock, acoustic, pop and metal and occasionally listen to EDM songs which are doing the rounds on the radio and charts.

Disclaimer - I would like to thank ItsFit for sending me the Fusion to test and review. I am not affiliated with the company or any of its sellers and write this review with an unbiased opinion regardless of how the review turns out.

Links – ItsFit Website | Fusion ($950)

Fusion can be ordered as universals or customs. Itsfit offers numerous shell and faceplate customization options where imagination is the limit.



Genre preferences - I majorly listen to rock, acoustic, pop, metal, and occasionally popular EDM songs.

About Itsfit - ItsFit is a Vietnamese company, who have been re-shelling IEMs for the last 3 years and only recently launched two of their own IEMs, R3 and Fusion. In my opinion, ItsFit is a brand to watch out for as they have good R&D experience, interesting tech in their IEMs and some of the most attractive shell designs I have come across. They regularly receive high praise for their re-shelling and recently Fusion has been making waves too.



Technical Specifications -

• Configuration – 1 Magnetostatic (Treble) | 2 BAs (Mids) | 1 DD (Bass)
• Freq. Response: 4Hz – 40kHz
• Sensitivity: 98 dB/mW @ 1kHz
• Impedance: 13.1Ω @ 1kHz
• Isolation: -26dB

Included in the box - ItsFit packaging is minimalistic but cool, as they focus on the things that are important; stuff that you’ll actually use.

• In-ear monitors
• 2-pin cable
• 2 sets of ML ear tips
• Hard case
• Carrying pouch
• Cleaning cloth
• Cleaning tool
• Handwritten welcome cards
• Warranty card

Build Quality - ItsFit IEMs have fantastic build quality, period! They also have some of the most interesting and attractive shells designs in the industry that I’ve come across. Fusion has three vents which look like grip holes in bowling balls. IMO, it is a very interesting design for dynamic driver venting. It not only serves its purpose but also looks very cool!

It is made out of resin and has very cool nozzles that are transparent and different from the shell color. They kinda look like a different part that is glued to the main shell but I don’t know if that is the case or not because it is very well integrated. As you would expect from a company that solely provided a re-shelling service for a few years, the shells have absolutely no bubbles or residue glue visible. The shell customization I requested for Fusion came out perfect! You can see for yourself how good it looks in my pictures. They came out equally great!


Picture Courtesy - Kien @ ItsFit

Cable – Fusion comes with a silver-plated copper cable which feels and looks very good. It has nice looking and very solidly build connectors and jack. I love the grey-ish color they have. Cable has a nice braid and very little microphonics. Though I’d love to see an UP-OCC kinda cable included with Fusion, I actually have no problems with the stock cable.

Hardcase – The included case is similar to what comes with 64 Audio IEMs. I personally like these cases since I’ve been using them for a lot of years.



Fit and Comfort - Fusion's shells are semi-custom shape and are small enough to fit most ears. But the fit and comfort completely depends on the choice of ear tips. What makes ear tips difficult to choose is that Fusion's sound signature is a bit tip dependent and changes with snugness of fit. So you gotcha mix and match and see which ear tips sound the best and which provide the best fit. The ItsFit semi-custom universal shells aren’t as ergonomic as the ones from Fearless or BGVP as the latter work pretty well with multiple types of ear tips. In my case the nozzle needs longer ear tips for a snug fit. Though if you choose the right ear tips, ItsFit shell can fit as snugly as the ones from the other two companies. So choosing the optimum ear tips is important. Sadly, ItsFit do not provide a variety of ear tip options in the package. So, having a collection of different kinds of ear tips will help.

Here are some ear tip options that I settled on.


Snuggest Fit

Best Sound

Noise Isolation - The ear tips that provided the snuggest fit of course had the best isolation too and the isolation was as good as it can get for a universal shell. Though Fusion’s noise isolation is slightly less because of its vented design.

Sound Analysis – Fusion has a nice quirky fun tuning which makes songs that you’ve been hearing for a while suddenly become livelier, more energetic and fun. Fusion being a tri-brid has 3 different kinds of drivers and each driver pitches its own character in a very nice way. It is highly resolving, open sounding and dynamic, which makes it highly addictive. I funnily think that it is the best sounding IEM in my collection for Karnivool’s Sound Awake album, which is one of my favourite progressive rock albums. It is as if Fusion was tailor made for that album. Haha.

Let’s dig in deeper to know more…

Note – Fusion's sound signature changes slightly with different ear tips and fit. It shines exceptionally with some. So, I suggest you tip roll and experiment as the sound can vary between bright to balanced to slightly warm depending on your choice of ear tips. I’ve used wide bore softer silicone ear tips for the sound analysis.


Picture Courtesy - Kien @ ItsFit

Bass – Sub-bass has very good extension down low and in fact has more presence than mid-bass. I had gotten so accustomed to mid-bass leading the charge that Fusion sounded the good kinda different to me in the first listen in comparison to other IEMs I was testing. Sub-bass has more character than rumble, though it can rumble pretty well too if a song demands. But character is what wins for me. Mid-bass has good presence too and overdriven bass tones of bands like Karnivool, I Am Giant and Muse sound super crispy and snappy. Bass overall has more lively character than dominating presence. It is well defined, fast, dynamic and even sustains pretty well. For example, bass in Twenty-One Pilots’ Hype’ and Walk the Moon’s ‘Shut Up and Dance’ has very good character, deep sub-bass, crispy mid-bass presence and punch while still staying more fun kinda neutral rather than overpowering.

Mids – The transition from mid-bass to the midrange is very linear. Mids are highly musical, have very natural timbre along with great resolution and clarity. The balance of mids though is pushed a bit behind bass and treble. Midrange body is neutral-ish, though neither too full nor too thin. Upper mids have 2 primary peaks, one around 2.5-3kHz and another one around 5kHz defining the upper midrange character. Vocals are exciting and lively and even background vocals in songs like Coldplay’s Orphans have great resolution and clarity. Drums sound more lively than warm/earthy. Guitars and orchestral instruments have good attack and presence with a neutral body and very lively natural timbre, owing to Fusion’s linear lower mid-range and good shine in the upper mids.

Treble – Fusion’s highlight and USP is surely the Magnetostatic driver. I had only heard of Magnetostatic drivers in theory but had never come across one in action until I got the Fusion. The treble extends very well, is super crisp, open and sparkly (the good kind)! It contributes majorly to make everything sound exciting and livelier. Cymbals sparkle a bit more than neutral, though do not get splashy. Vocals have good rich sparkle and acoustics have that extra zing. The Magnetostatic treble character though is unlike BAs or DDs and so might need some getting used to. Once you adapt to its character, you’ll see how well it integrates into Fusion’s signature. But treble sensitive people should tread with caution (always), since appreciation will depend on preferences and threshold of treble sensitivity. Also, as I stated previously, Fusion’s treble character changes a bit with different ear tips and I highly suggest tip rolling for best results. I initially needed a bit of ear burn in, 5-10 songs maybe. My excitement levels were rising song by song and by the end of my ear burn in period, I was enthused and was already onto checking all my favorite songs and how they were sounding on Fusion. It is now one of my go-to IEMs to listen to music every day.

Soundstage, Imaging and Separation - Fusion has a nice big, wide and open soundstage. Width and depth both are very good. Imaging is very precise and pinpointing even the quietest instrument in the mix is quite easy. As for separation, Fusion much like Shozy Pola39, shows that great results can be achieved by selecting best drivers for the job and good tuning talent.



Comparisons -

CustomArt Fibae 7 ($1100) – Right off the bat, Fusion sounds more modern, energetic and exciting whereas Fibae7 is warmer of the two. Fibae7 has warmer bass and slightly stronger feeling of bass impact whereas Fusion has more sub-bass and dynamics. Fibae7 has a Harman kind of dip in the mids whereas Fusion has a more linear approach. Fibae7 has substantially more upper mids presence with a forward presentation than Fusion. Fusion on the other hand feels more natural and lively there. Fusion’s treble is more extended, present and lively whereas Fibae7 has a natural roll off post 5-6kHz. Both have nice wide soundstages. Choosing one between them completely depends on your preference and liking.

Fearless Roland ($1000) – They are polar opposites in a way. Roland is a darker IEM whereas Fusion is energetic and lively. Fusion has more sub-bass as well as overall bass presence. Roland is quite reference like from bass to starting of upper mids. Post that, both have good upper mids presence but Fusion because of its livelier signature, has more resolution in the mids as well as overall. Fusion’s treble is way better extended and open whereas Roland has a sudden treble roll off post 5kHz. Fusion has a livelier open soundstage whereas Roland has a decently wide soundstage but because of it being dark, the feeling of openness is subdued.

Shozy Pola39 ($950) – This is a tough one! Both Pola39 and Fusion have their own characteristic treble character which is their strength and also what makes them uniquely cool. Fusion has a magnetostatic driver for treble whereas Pola39 has a dual EST driver. Both have a very good bass character and presence from their respective dynamic drivers but Pola39’s is a bit more present while Fusion’s is more controlled. Both have good natural mids but Pola39’s mids sound slightly warmer and balanced whereas Fusion’s mids are slightly pushed back but equally dynamic and punchy. Pola39 sounds slightly warmer till the treble as compared to Fusion and then both of them gain their characteristic treble character where Pola39’s is more open & airy and Fusion’s is slightly fuller and ever so slightly upfront in comparison. Both have a nice wide soundstage. Choice between the two is tough as they both have a similar take on a ballpark idea of sound but still quite different and cool in their own way.

BGVP EST8 ($799) – EST8 and Fusion are again quite different. Fusion sounds very modern, energetic and lively whereas EST8 sounds warmer. Both do bass very well but Fusion has a dynamic driver with higher resolution, nicer character and energy. Fusion has better mids with more resolution, better details and more liveliness. Fusion’s treble has more sizzle, sparkle and energy whereas EST8 is smoother, more natural and warmer.

Conclusion - ItsFit is not a new company as such. They’ve been re-shelling for the last 3 years while doing R&D on the side to develop their own products. What is amazing is that instead of choosing a safe tuning for their first products, they in fact got experimental with new driver tech (Fusion) in one and reference style tuning (R3) in the other. Both are not easy to execute! Fusion is a very lively and exciting IEM which makes your music feel extra special. Also, it can be ordered as universals or customs and you can take my word that their designs, shell quality as well as finishing is one of the best in the industry. Fusion gets 2 thumbs up from my side. If your budget is around its price, surely give it a shot.



Gear used for testing and review -

• Logic Pro X session with hi-res test tracks played through Universal Audio Apollo or Focusrite Clarett Pre X audio interface headphone out.
• Hiby R6 Pro
• Oneplus 7 Pro

Reference Songs list -

• Foo Fighters – The Pretender, Best of you & Everlong
• Coldplay – Paradise, Up in flames, Everglow, Orphans
• Dave Matthews – Shake Me Like a Monkey
• Ed Sheeran – Thinking out loud, Bloodstream & Galway Girl
• Chainsmokers – Somebody, Sickboy, This Feeling & Closer
• Twenty One Pilots – The Hype
• John Mayer – Slow dancing in a burning room, Stop this Train & Say
• Gavin James – Always & Hearts on fire
• Switchfoot – Meant to live & Dare you to move
• Linkin Park – Papercut, Somewhere I belong & Talking to myself
• Walk the Moon – Shut Up & Dance
• Lifehouse – All in all & Come back down
• Niall Horan – Slow Hands, Mirrors & The Tide
• Breaking Benjamin – Diary of Jane
• Karnivool – Simple boy & Goliath
• Dead Letter Circus – Real you
• I Am Giant- Purple heart, City limits & Transmission
• Muse – Panic station
• James Bay – Hold back the river

The new ItsFitLab Fusion is a worthy contestant against pioneer audio manufacturers and even sets a new benchmark for top of the line models.

Disclaimer
This review is originally posted on Headphonesty. Thank you, Kien, CEO of ItsFitLab for sending me the ItsFitLab Fusion in-ear monitors (IEMs). They were provided to me free of charge in exchange for my honest review and opinion.

Introduction
Led by CEO Kien Nguyen, ItsFitLab evolved from a small lab which specialized in sound and audio component research to a custom in-ear monitor (CIEMs) brand in Vietnam. Leveraging the global growing trend of CIEMs, ItsFitLab applies the best optimized sound technology. That, combined with experience in local handcraft, produces sonically and physically pleasing CIEMs for their customers.

The philosophy adopted by ItsFitLab is that “everyone deserves a better sound experience. We support our customers from consultation till we hand you the final product to assure complete satisfaction.”

The Fusion is their current top of the line (TOTL) product. As the world’s first triple hybrid IEM with Magnetostatic™, the Fusion is the result of ItsFitLab’s quest for truly innovative in-ear technology. According to ItsFitLab, the most remarkable trait of the Fusion is its ability to produce an incredibly wide soundstage which ultimately recreates the performance feel. Without further delay, let's find out more!

Triple hybrid IEMs utilize three different types of drivers to cover the sound spectrum. The strengths of some types of drivers cover the weaknesses of the other types. This can improve the overall performance of an IEM compared to conventional non-hybrid configurations.



Unboxing
ItsFitLab really put in effort to make the packaging classy and suitable for a TOTL product.

The Fusion comes in a black cardboard box. The box is plain and blank with the exception of the brand logo and name.

Opening the box, users can immediately see the Fusion on the upper part. Located at the lower part of the box is an envelope containing user manuals, the warranty guide, and a discount code for the next purchase.



Underneath the envelope, there is a hard case containing the stock cable, a soft pouch, and a fiber cloth. Removing the Fusion from the box, there are four pairs of silicone ear tips and a cleaning tool sitting underneath the Fusion.


Technical Specification

• Configuration: 1 Magnetostatic driver (high), 2 Balanced Armature drivers (high-mid & mid), 1 Electro-dynamic (low)
• Frequency response: 4Hz – 40kHz
• Sensitivity: 98 dB/mW @ 1kHz
• Impedance: 13.1Ω @ 1kHz
• Isolation: -26dB

Build
ItsFitLab uses acrylic shell for its universal line-up including the Fusion. The faceplate can be customised based on users’ preferences. I chose the most basic design - with ItsFitLab logo and brand name on both sides.



The shell is relatively big when compared to other models that I recently reviewed, such as the Jomo Audio Haka and Symphonium Audio Aurora. This could be because additional space is needed to cater to the triple hybrid configuration in the Fusion. Although it is comparably larger, it is still an acceptable size.

There are three bores on the nozzle. ItsFitLab uses traditional passive filters in the Fusion. Each sound bore is connected to a specific type of driver. With this implementation, the manufacturer believed that reproducing sound at extremely wide frequency response without losing any sound details is efficient. There is a lip on the nozzle to hold the ear tips. This makes ear tip rolling easy for the users.

'Ear tip rolling' is the process to find a suitable ear tips that gives users the best seal, isolation, and sound.



Moving to the top of the shell, a recessed 0.78mm 2-pin port is utilised for the Fusion. A recessed 2-pin port is sturdier compared to the conventional flat 2-pin port because the largest area of the pin is protected by the shell. More shocks can be absorbed before breaking the pin.



The stock cable provided in the box is a four-wire twisted cable with a 3.5mm unbalanced jack. There is no available information with regards to the material used for the cable but I believe it to be silver plated copper (SPC) which is commonly used.

The jack is sturdy and built with a strain reliever, making it durable and solid. On the jack, we again see the logo. Moving to the Y-split, I favor its simple design because a bulky Y-split could impose microphonics when the cable moves. There is a chin-slider to provide a more secure fit. At the 2-pin connector, the heat shrink ear guide ensures that the cable stays behind the ears.


Fit and Isolation
The acrylic shell is well polished. Its surface of the shell is smooth to the touch. I don't experience any discomfort when wearing the Fusion. I believe the overall experience will be even better if it’s custom made. Although having a large shell, the Fusion sits in my ears perfectly with the correctly sized ear tips.

I am currently using it as my daily commuting option because of its ability to block out external noises - an impressive feat considering its three vents on each side to mitigate driver flex.

Driver flex is what happens when the driver bends due to the pressure of air against it. Usually, it occurs when you're inserting the IEM into your ear and air in the shell creates pressure to bend the driver.


Drivability and Pairing
It is always a concern with regards to drivability when a triple hybrid is involved. The first few triple hybrid models in the market, such as Jomo Audio Trinity (electrostatic triple hybrid) and Noble Khan (piezoelectric triple hybrid), are power-hungry beasts. A significant amount of power is needed to properly activate the electrostatic or piezoelectric drivers in IEMs due to the low sensitivity of the drivers. Without proper driving, they sound awkward.

Rated at 13.1Ω at 1kHz for impedance and 98 db per mW at 1kHz for sensitivity, the Fusion is less power hungry. In fact, it is actually as easy to be driven as a pure balanced armature (BA) drivers configured IEMs based on my experience.

With the current flagship models of iBasso, DX220, I only need volume level of around 70/150 on low gain for most recordings. This makes the Fusion unique and easy, with no external amplifier needed.



Sound Analysis
Listening to the Fusion is like the feeling of sitting near your fireplace at home - comfortably warm.

The overall sound signature is smooth and warm. The Fusion hits the sweet spot - enough warmth is injected to produce the truest sound without compromising any details.

The soundstage is another pleasant surprise from the Fusion. Instruments and vocals are accurately positioned in their respective places and every note is precisely presented with amazing layering. I think this could be one of the best soundstages I’ve ever experienced within the price range of USD$1000.

The depth is extending deep by the 10mm electro-dynamic drivers while the height is reaching high by the 8mm magnetostatic driver. Based on my research, the Fusion is the first and only IEMs with such a unique configuration. This opens the door to other manufacturers to explore this configuration with a confirmed positive result.



Lows
The coupled dynamic drivers handle the lows decently - the body is full and extends deep.

As mentioned earlier, the lows are handled by a 10mm electro-dynamic driver. The produced bass is refined and balanced. It has good extension in the sub-bass, creating rumbles. When slowly moving towards the mid-bass and upper-bass, the body starts to shrink, ready to create space for the mids.

This makes the bass well controlled. It's balanced because of its position. Its power doesn't overshadow the mids and highs. All three frequency spectrums can co-exist with no collision or congestion.

The attack and decay speed of the lows is also handled well - it is well controlled in its own region and the decay speed is in the perfect balance between bleeding to other regions and being too technical or dry. This makes the bass precise and accurate and even adds to the overall presentation.



Mids
The performance begins with reserved lower mids. However, they start to shine when moving towards the upper mids.

The lower mids, compared to the higher, are more reserved due to the transition from the slightly recessed upper bass. However, this reserved profile does not cause the lower mids to be shadowed. Male vocals are well resolved and lively with warmth injected from the overall sound signature.

Moving towards the upper mids, the performance shines even brighter. This makes female vocals to be sweet but not overwhelmingly bright. It is balanced by the warmth of the sound signature. The soundstage created allowed the vocals to stretch, yielding breathy, airy, and spacious vocals.

I would like to emphasis the layering in the Fusion. Every note from each frequency region plays coherently well together.



Highs
This is the spotlight of the show; the Fusion redefined how highs should sound.

If I were asked to mention the most unique selling point of the Fusion, I would pick the highs. It is well-extended, smooth, and sweet. No adjective can accurately describe how impressive it is. Utilizing a new technology, the Fusion produces highs in the most neutral and natural manner. This could be the most comparable to a live performance I have ever heard.

The cymbals are crisp, smooth, and full. The notes are not overly harsh while it has a sufficiently thick body to sustain the process of decaying. This makes every note in the highs to extend well and the overall fidelity is improved drastically.

A lot of manufacturers face the same issue with electrostatic drivers - the highs overshadow the lows and mids, making the IEMs untamed, soaring in high pitch. I would say ItsFitLab successfully proved that the magnetostatic driver mitigated the issue and this will be a new benchmark for triple hybrid IEMs.


Conclusion

The Fusion retails for USD$950 and users can customize the faceplate as well as choose between a universal or custom shell. It can be ordered on ItsFitLab official website. An order for the universal Fusion can generally be fulfilled in 3 to 7 days while the made-to-order custom Fusions will require an additional 3 to 4 weeks upon receiving the ear impression.

The ItsFitLab Fusion is the new benchmark for TOTL products as well as triple hybrid IEMs. ItsFitLab’s ability to use strengths from different type of drivers to strengthen the performance of the Fusion in every frequency spectrum makes it one of the most competitive options within its price range.

As a relatively new company, I would like to salute to ItsFitLab for showing their passion, dedication, and wholehearted effort in making an outstanding IEM through the release of the Fusion. I hope that I will have a chance to experience more IEMs from ItsFitLab.

This is the first time I am giving five stars to an IEM. I am totally sold to the sonic performance of the Fusion.

Listening notes
I spent over a hundred hours with the ItsFit Lab Fusion, listening to Cayin N6ii (A01 and T01 motherboard) and the DX160 mostly with the DITA Oslo using 4.4 balanced.

Disclaimer
I have purchased the Fusion during the end of October Sale with 30% off. As usual, this review is my honest opinion. No incentive was given for a favorable review.


Fit, Build & Isolation
I chose a « plain » cyan transparent design for my Fusion, the picture hardly do justice to the color (hard shade to portray faithfully) but the transparency clearly show top notch craftsmanship, showing the dynamic, balanced armature and magnetostatic drivers as well as the 3D printed acoustic chambers that bypass any need for passive filters. The Fusion are beautifully engineered and the build is flawless, simply the best fit I have had along with my Custom Art IEMs. Hats off to Kiên and team here!



Introduction

ItsFit Lab is a very young upcoming manufacturer based in Vietnam which managed to get known very quickly and it’s not surprising. I mentioned this above the packaging as well as build quality is as good if not better as well established companies. ItsFit Lab certainly is serious about getting things done well from the get go.

The Fusion is their second IEM after the 3 BA reference R3 and it’s already a sales hit. In a world where most tribrids use eStats for treble, Kiên decided to build the « world’s first tri-brid earphone with Magnetostatic™ ». A good way to get noticed but a daring endeavor to pick a new driver tech that has never been implemented yet considering the number of disappointing tri-brids that popped up when the eStats driver came out.

ItsFit Lab also decided to do quite a bit of work and innovation into the acoustics design as well, using « exclusive sound chambers using 3D printing technology. This technique helps delivering original sound through separate signal channels without sacrificing sound with traditional passive filters. This proves to be efficient in reproducing sound at extremely wide frequency response (10-40000 Hz) without losing any sound details. » I have had a few IEMs with advanced acoustics : IE800 and Black have helmholtz resonators, Solaris also features acoustics chambers with T.A.E.C and P.T.C and it plays a big role into soundstage and distorsion.

With the Fusion, Itsfit aimed at building « a true innovative in-ear that conquer even the most demanding records. Fusion’s soundstage crossed all lines to be a premium in-ear monitor that brings to your ear the extremely wide and deep soundstage of a pro open-back headphones in a tiny, portable earphones. The super luscious highs, detailed & transparent mids and super tight lows now packed with superb space performance, bringing you unforgettable listening experience. »

Somewhat of a bold claim… does the Fusion hold its promises?

Let’s see!


Sound
The first thing that struck me listening to the the Fusion are : bass, treble, clarity, soundstage, imaging. Bass and treble are clearly stars of the show, because they do provide all the excitement in the Fusion’s signature. The Fusion features a toe tapping, tight and perfectly controlled bass with strong sub and spot on mid bass presence. It also features lively lower treble with good energy but done right, as it’s not a harsh or fatiguing treble either. The upper treble is well extended and provides superb clarity and air. Soundstage is quite wide, tall and deep with a fantastic image both pinpoint precise and coherent.

While bass and treble are the star of the show, the mids are the cornerstone of the Fusion signature : they provide coherence and balance to the whole tuning. I read the Fusion as being a technically strong fun IEM, with plenty of excitement but done right (good control, superb imaging, tonally accurate) and in a balanced way. This is somewhat of an unusual signature or at least I fail to find a similar combination in any IEM I have auditioned.

Now, let’s dig a bit deeper into the Fusion’s bass, mids and treble!


Bass
The Fusion is not a bass-head IEM it’s not a massive bass ala Campfire Solaris or IER-Z1R – subs don’t have the same subwoofer like presence – but the dynamic driver is sure able to push air with nice sub rumble and get you toe tapping.

Most impressive is how tight the bass is : the bass presentation is clean and absolutely flawless technically with superb control and layering. You might find yourself discovering a lof of details you didn’t know where there. Note attack is frank and energetic, with very good snap and short decay, the Fusion bass is quite fast for a dynamic driver powered bass.

It’s not as fast as the best balanced armatures but still very good in that respect. The Fusion has no problem keeping up pace with faster tracks or provide a very articulate rendering of bass heavy genres. It’s always a good indication when I spend more time than usual listening to punchier albums and tracks with an IEM and it certainly was the case with the Fusion.

To me the Fusion has an audiophile bass with a good touch of fun and I found myself pushing the volume a bit more than usual, as it’s a great experience with the Fusion where everything remains absolutely clean of any distorsion. Note that the Fusion is vented and it probably helps there along with the custom 3D printed chamber (acoustic work definitely paid off). I didn’t notice any perceptible leaking from the vent and people right next to me didn’t complain.


The three vent holes for the Fusion bass driver
The only thing I could be left wanting is a bit more mid bass presence and textures especially on double bass on Jazz tracks, but I am nitpicking here

Mids
Mids are interesting because you could think from what I wrote in the overall sound impressions that the signature is V or U shaped with focus on both bass and treble. Well, it’s not because the mids are definitely not recessed. In the line of the overall signature the mids are clear and clean with very good separation. The Fusion certainly features mids that won’t add any warmth unless the source provides coloration, it’s a reference tuning in my opinion.

Lower mids are clean and balanced, a good call given the bass presence and there is no congestion at all. Vocals and lead instruments are clear and slightly forward in the mix, very articulate with and quite accurate in tone. Upper mids are less present, the mids are as smooth as they can : attack and decay are a little slower than the bass.

I confess, while the Fusion is a fantastic all rounder when listening to Jazz albums the Fusion lacked a bit of upper mids presence which was apparent on saxophones or trumpets. On the flipside the Fusion features a fatigue free midrange.

Treble
Treble was a question mark given that the Fusion features a new driver technology that has never been used in an IEM before. It also was a bit of a concern as I have been so disappointed by the first implementation of eStats in earlier eStat tribrids… So what is a magnetostatic driver and why use them? As stated on ItsFit’s website « Magnetostatic™ drivers use two pairs of permanent magnets located symmetrically and independently from a membrane in between. This ultra-thin 5-layer erromagnetic membrane layer with very high magnetic permeability moves its entire surface without any dead point, minimizing sound loss, transfer delay and distortion ».

The promise of fast transients and low distorsion is certainly interesting and a potential contender to eStats and balanced armatures, and I was really curious about the Fusion’s treble. How did Kiên handle the world’s first implementation of the magnetostatic in an IEM?

Well, let’s spare the suspense, it’s really perfectly integrated in the Fusion’s signature. The Fusion features both superb upper treble extension and exciting but non fatiguing lower treble. This is key to the soundstage air and the overall clarity of the Fusion signature as well as the fantastic imaging ability.

Of note is the very accurate treble tone, and the satisfying weight to treble notes. This is one very differentiating aspect of the Fusion’s treble compared to the eStats I have heard so far. This is not a treble with an ethereal quality, but a physical treble and piano notes have delicious weight when called for. Transients are very fast, but noticeably less than eStats tribrids like Vision Ears Elysium.


Verdict
The Fusion is ItsFit Lab’s flagship and only second IEM after the R3, one can only imagine the big stakes around its launch for the young vietnamese company. Choosing to pick a new driver technology and be first to implementing it was certainly bold and this time the saying is true : “Fortune favors the bold”.

Except that fortune has no part there : ItsFit Lab build quality, tuning mastery and customer service is up to par with the best in the business and it’s no small feat. Yes, ItsFit Lab is still a small shop and the Fusion’s success means a bit longer build time but this is a ransom of success rather than a shortcoming and any similarly sized company would have faced the same challenges. I was lucky to be among the first to order during the sales and Kiên helped me get my Fusion in time for my birthday which was therefore quite an happy one

Does the Fusion deliver on its promises? “Extremely wide and deep soundstage” Check, although probably not up to par with open back headphone – that’s probably not possible – but still top tier very open sounding and fantastic imaging. “Super luscious highs, detailed & transparent mids and super tight lows.” Check, the highs are clearly a highlight of the Fusion and participate in the clear, open souding signature. Check, the mids are clean and clear with a very accurate tone. Check, the lows are indeed tight with superb control.

If you’re looking for a punchy and clear sounding IEM with great soundstage and fantastic imaging, then you’d be hard pressed to find a better candidate than the Fusion especially at its price point. The Fusion delivers great value for money featuring flawless technical foundations, a highly coherent tuning and a superb build. Competitors take note, a strong challenger hits the market and it hits hard!



Packaging and accessories
The Fusion are delivered in a quite rare packaging for a custom IEM : the box is sealed with plastic. The unboxing experience is very nice as well with a hand written thank you note, a metal protective case customize to your name and the usual pouch and cleaning tools. The stock cable is above most offerings with a nice braided build. Note that the Fusion also exist as universal IEMs.

• 1 x ITSFIT Protective premium Case
• 1 x Cleaning Tool
• 1 x 48″ Detachable Premium black Cable
• 1 x Soft cloth
• 1 x Soft portable bag
• 1 x Product Manual
• 1 x Warranty note

Specifications

• Driver configuration:
  1 Magnetostatic driver – high
  2 Balanced Armature drivers: high-mid & mid
  1 Electro-dynamic: low
• Freq. Response: 4Hz – 40kHz
• Sensitivity: 98 dB/mW @ 1kHz
• Impedance: 13.1Ω @ 1kHz
• Isolation: -26dB

I'm going to keep this review rather brief, because the Fusion has already been covered pretty extensively

Note: The rating I've given the Fusion has taken its price point into account, while the sound judgements are done with the same scrutiny as any IEM, whether it costs 100 or 10,000$.

First and foremost, I can't stress enough just how good the service is. ItsFit have absolutely nailed it, and they most certainly know how to build a brand name. Any questions I had were answered in minutes, instant and lightning quick responses at various times of the day and night. Had a long and pleasant conversation with Nguyen, and it was a delight speaking to him about his product. He assisted me plenty with the design choices, as we discussed several options before settling for white shells with a golden paw print of my doggo. Again, absolutely amazing service, could not ask for better or even dream of it

The packaging has been covered already - you get a little box, with a case and your IEMs inside. Nothing much to be covered here, personally I was pleased with how simple and clean it was.

I opted for the rush order on mine, costing me 200$, but it really was lightning quick - ItsFit received my impressions on Wednesday, the IEMs were shipped out on Saturday, of the same week. Couldn't believe it myself haha.

The build quality on these is absolutely perfect. The colours look stunning, they fit very well - mostly a comfortable fit as opposed to a really tight one, with decently deep insertion. What really deserves attention are the sockets - all my cables fit absolutely perfectly in there, not too tight or loose, just snap into place like they were meant for each other. Almost no other IEM I've owned, including from companies like VE or 64Audio (customs), not to speak of Noble and their sockets, is able to match ItsFit. If you have experience with the universal 64 line, it's something like that - pure excellence







On how they sound - definitely give these some time to burn in, the treble tends to be really spiky and weird until the magnetostatic driver starts functioning properly.

Once they do however, you're in for a treat. Amazing bass - tight and precise, with excellent subbass quantity (possibly somewhat elevated). The treble is the other aspect that really shines, and the mangetostatic driver really makes the magic happen. It is both forward and somewhat elevated, but with excellent sparkle and quality - not a hint of dryness. I've only heard that driver in Noble's M3 before, but the Fusion benefits from a much, much better implementation.

The midrange is the supporting frequency region for the bass and the treble - it is definitely not recessed (can't even say it's a U shape, even less a V), but it feels like more of a connection than a self standing, ready to wow you midrange. It lacks texture and some detail, which is the only real weakness of the IEM. I don't think that's a mistake per se, but it's there to really let the treble and the bass get some additional attention. Given my preferences, and extreme midrange pickiness, there's a good chance these observations are somewhat inflated, and in reality it's pretty decent on its own

The imaging is insane on these - the kind of imaging you'd get on a 3000$ pair of IEMs - pure TOTL material. The soundstage is pretty wide, and very deep. Couldn't really expect any better. The clarity also stands out, as they've been tuned to deliver exceptional clarity. Detail retrieval in the bass and the treble is great, acceptable in the midrange. The Fusion does sometimes struggle with muddier/more complicated tracks, mainly really old rock or jazz recordings, where you have tons of stuff going on at all times. The instrumental separation is normally great, but can get somewhat "overloaded" in such cases.

In terms of pairings, I find the Fusion to be pretty responsive to cable rolling and source swapping. My current favourite is the ALO Audio Pure Silver (reterminated to 2pin) and the RME ADI 2 DAC. Paired with the SP1000M the treble becomes a tad excessive (even for me). I also tried the Fusion with the Silver + Gold from Plussound, but the pairing was far from ideal - I'd recommend a pure silver cable, as that is where the soundstage width is optimal and the clarity boosted even further

Please once again note that my criticisms and evaluations have not taken the price level into account in any way or form, but are rather the same evaluation criteria I'd apply to the 64Audio Noir or VE Erlkonig.

If you're looking for a balanced presentation, with excellent clarity, imaging, bass and treble, I would heavily recommend the Fusion. Its built by some truly wonderful people that have made it an absolute pleasure to purchase from them, and I will most surely be returning in the future - or well, I already have, as they're working on a reshell of my Noble Katana

Introduction

Fusion were purchased directly from Itsfit Lab.

Itsfit Lab is a Vietnamese company based in Hanoi and whose history is particularly short. Currently sold for $950, Fusion are hybrids composed of one 10 mm dynamic driver for bass, two balanced armatures for mids and high mids, and one 8mm magnetostatic driver for treble. The shell seems solid and the kraftmanship is of a very good level.
They are available in universal or custom, and feedback is done on a universal model. The stock cable in 3.5mm jack is very well made and already allows you to take full advantage of the quality of these inears.
https://itsfitlab.com/fusion

Sound

Fusion signature is rather neutral with a small bass boost and 3 peaks well audible with a sweep at 2500, 5000 and 8000Hz.
Here are the Crinacle measurements (uncompensated) to compare with the InEar PP8 (with bass boost).



What strikes you from the beginning with Fusion is spatialization. The stage width is excellent, and well above average, at the PP8 level and therefore superior to what the Trinity SS offers. The depth is not far off, and of the same quality as on the Trinity SS, which is no small thing to say. The height is also of the highest order. The result is a beautiful scene like one encounters little, in the head certainly, but airy, and which allows an exceptional localization of the music.

The bass is fast on impact, like on Trinity SS, but has a slightly slower decay that results in a softer sound. They go down extremely low with subs of an exemplary texture, and remain very legible despite this. They do not tarnish the rendering of the mids at all because of their very good linearity. The bass of PP8 are less present and softer, without the typical DD impact.



Low-mids (250 to 500Hz) is warm and thick, it provides a foundation for voices and instruments. The Mids (500 to 2000Hz) breathe through the relative "hole" around 1000Hz and the rise to 2000Hz. The High-Mids (2000 to 4000Hz) centered on the 2500Hz peak is soft and allows harmonics to develop well.
All this gives mids positioned a little forward, with a beautiful musicality, and with mild tone.
In comparison, the Trinity SS midrange is more recessed at the bottom and more open at the top, which leads to a retreat of the scene and more potential hardness depending on its sensitivity. The PP8 mediums have a restitution that goes in the same direction as that of the Trinity SS, but in a less intensive manner.

The treble provided by the magnetostatic driver is very extended but you will not find an ounce of hardness or sibilance. They are very natural, very fast and smooth, and are certainly not unrelated to the scale of the scene. The 5 and 8kHz peaks give life and space to the music, and the 6.2kHz dip on the measurements does not seem to be as present when listening to music.
The PP8 treble is clearly more flamboyant and more linear but do cut earlier. The Trinity SS is a little duller and seems to cut a little earlier too, but seems as fast and more detailed.



Separation and transparency are very good and almost comparable to what can be found in today's market leaders such as the Elysium or Trinity SS, but above what PP8 offers. On the other hand, definition and resolution seems a little behind the same tenors, and even the PP8.

When playing with the tips, I prefer Whirlwind and Spiral Dots which provide a little more air to the sound and a pleasant lightness compared to Sedna. The fit is also outstanding.
For cables, compared to the standard cable, the PW1950 provides a little extra on all levels while maintaining the initial homogeneity. The PW1960 2 strands as for him makes the mids move back and offers a more out of head scene that comes in an arc of circle, and a more analytical and technical rendering.

Final Thoughts

For its second inear and first hybrid, Itsfit Lab makes a strike by offering a very high quality restitution for less than $1000. Impact, legibility, intensity, air, it's undoubtedly high-end. In my opinion, however, it lacks a bit of definition and resolution to titillate the market leaders, who are nonetheless sold at a much higher price.


"Resolution is the ability to individualize a voice or instrument"
"Separation is the ability to feel space between the various sound sources"
"Definition is the ability to perceive as much information as possible"
"Transparency is the ability to transcribe the nuances and subtleties of music"


My topic on Tellement Nomade here : http://www.tellementnomade.org/forum/viewtopic.php?p=671123#p671123

*This review was originally published on my blog.

Itsfit is a relatively new company based in Hanoi, Vietnam that manufacture’s custom in-ear monitors (CIEMs). Despite only recently opening for business, they’re already delivering on a level you’d expect from a well-established brand in terms of product quality and user experience. In today’s review, I’m taking a look at the Itsfit Fusion, a tribrid custom earphone with a magnetostatic driver plus a dynamic, musical and immersive sound.

Price $950
Website: https://itsfitlab.com/

This sample was provided for the purpose of an honest review. All observations and opinions here are my own based on my experience with the product.

Package and Accessories



The unboxing experience begins with a black box adorned with the Itsfit logo. This outer box was actually sealed in plastic; the first sign that I was dealing with a proper finished product and not just a branded DIY project.

Inside you’re greeted by a plastic carrying/storage case plus the rest of the accessories. What’s in the box:

• Itsfit Fusion in-ear monitors
• Hard carrying case
• Carrying pouch
• Cleaning tool
• Cleaning cloth
• Detachable 2-pin cable
• Warranty & documentation

So far, it’s a fairly standard CIEM package, however, there are some things that stand out, most noticeably the uniform branding and feel of a finished product. For a company that is just starting out, there is a high level of polish here.

Build Quality and Design



Let’s talk about the internals before we get to the actual design. Internally, the Itsfit Fusion has three types of drivers which were chosen for their optimal performance in specific frequency ranges. A 10mm dynamic driver was naturally chosen for bass reproduction, as they excel at moving air and creating authoritative lows.

For the core and upper midrange, a dual balanced armature driver was given the task; perfect for fast transients and instrument separation. Lastly, the most exotic of the drivers, the 8mm magnetostatic, which is in charge of the high frequencies.


Image courtesy of https://itsfitlab.com/
Itsfit uses 3D-printing technology which allows them to produce the shells with more consistency and with advanced features, such as 3D acoustic chambers.

In terms of build quality, the Fusion looks and feels fantastic. The shells have a uniform thickness thanks to the 3D-printing process and they feel fairly robust, although, you wouldn’t want to drop them of course. They come with recessed 2-pin sockets for extra durability as well.



Customization
When it comes to customization, there is visual product designer software on the website that lets you choose from a variety of colours and patterns for the shells and faceplates. You can also upload your own artwork or logo and you can communicate directly with Itsfit staff for even more options.

My unit came with the “Skeleton Leaves” heritage design complimented by cyan-clear and pink-clear for the left and right sides respectively. I’m delighted with the way they turned out. The skeleton leaves design is exquisite and of course, every leaf is 100% unique courtesy of mother nature.



Comfort and Noise Isolation
As always, the fit of your custom monitors relies on sending a good set of ear impressions. The website has a useful page with detailed instructions on how to get the best fit. It’s wise to print the instructions and share them with your audiologist.

In terms of size, my Fusion earpieces are about average among my custom monitors. They’re smaller than the LXear Pluto, slightly larger than my Empire Ears Bravado and are most comparable in size to my Custom Art FIBAE monitors.



The shells are beautifully finished and are very smooth all over. I can wear them comfortably for hours but again, your mileage may vary and is dependant on starting with a good set of impressions or 3D scan.

Noise isolation is par for the course in regards to modern 3D-printed customs meaning they block out a good 25-26dB of external noise passively so even playing music quietly will shut out just about all ambient noise unless you’re in an extreme environment.

Cable



The stock cable included with the Fusion was quite a surprise, as I was expecting to find the ubiquitous Plastics1 that comes with many custom in-ears. However, Itsfit includes their own custom cable and it’s a good one too.

It’s a twisted 4-core SPC (silver-plated copper) wire with glossy black sheathing. It’s thicker than the Plastics1 cables and handles really nicely. There is very minimal microphonics and the cable drapes comfortably without any springiness or kinks.

At the top are gunmetal-coloured 2-pin connector housings followed by heat-shrink ear guides. A small metal Y-split and plastic chin slider are next and the cable terminates in a straight 3.5mm plug. Each of the components is the same colour and have Itsfit branding on them. This is easily one of the nicer stock cables I’ve seen with a CIEM but I would love to see Itsfit add options for 2.5mm and 4.4mm balanced terminations as well.



Sound
Portable sources used: Shanling M5s / Sony NW-ZX300 / Soundaware M2Pro.
Desktop source: Windows PC > Foobar2000 > FiiO K3.

Alright, let’s get down to the meat of this review: the sound. The Itsfit Fusion’s defining characteristics are its clarity, timbre, tonal balance and staging. Too vague? Stick with me here, I’m getting to it. The overall presentation is one of balance, where the trinity of bass, midrange and treble are all on equal ground. A touch of warmth is added for intimacy and naturalness which combined with the staging and cleanliness makes for one very interesting performance.

Technically, Fusion can go toe to toe with the best of them and surpasses many of those that are similarly priced. It’s supremely confident in its presentation without being brazen, not like the new kid on the team with something to prove but more like a player at the top of their game.



Bass
Itsfit have chosen a 10mm dynamic driver for the bass reproduction and it pays off handsomely. The bass is boosted a little north of neutral but governed and balanced with the mids and highs. There’s plenty of force in reserve when required though and the Fusion has sufficient impact to work across any music genres.

The Fusion’s bass is simply among the best I’ve heard on a CIEM. It seems to dig down forever but it’s not sheer grunt that makes it special; It’s the depth of its extension coupled with its resolution and definition. It also comes from the naturalness in its weight and tone plus the clean leading edge and the relaxed but never loitering speed of its decay.

Listening to Hans Zimmer’s “Gotham’s Reckoning“, Fusion recreates the dark foreboding tones of the synth bass with a physical rumble and the potent drums of war with all their vast grandeur while sustaining just enough restraint to keep them in check.

Mids
The Fusion’s midrange is a mix of clarity, body and naturalness. It has pristine cleanliness but blends it with a musicality rich with detail and nuance. Instruments are neutral in size so they never sound thick or clammy nor are they analytically thin. Stage positioning is also neutral, allowing you to take in the full scene but keeping you close enough to feel immersed in the sound.

Vocals are rich yet articulated, whether male or female, the Fusion’s midrange is rendered evenly without any area taking precedence in the overall presentation. Perhaps the midrange’s greatest asset though is it’s natural timbre. That cleanliness has an underlying warmth that is ever so inviting but never cloying. Fusion’s mastery of midrange timbre is evident in tracks like Above and Beyond’s “Sun & Moon – Live At The Hollywood Bowl“, where it renders the instruments, vocals and the crowd with vivid naturalness.

Treble
So now it’s time to see what the fancy magnetostatic treble driver can deliver; Is it merely marketing buzz or does it really add value to the sound? Well, I’m a believer, let me tell you. Fusion’s treble is crisp and lively with a light halo that adds a touch of softness and body. A brilliant extension gives it abundant airiness while its tastefully even presentation keeps it smooth and fatigue-free.

There’s sufficient sparkle and shimmer but thankfully no sign of sizzle or sibilance. Given its calm delivery, it’s striking how it can still be so precise, detailed and accurate. There’s no evidence of compression or steeliness either – timbre is another box the Fusion’s treble ticks off with zeal.

Soundstage
Fusion’s soundstage is stately in its dimensions and very stable by nature. While that in itself is an achievement, it’s made even more extraordinary by maintaining instrument and vocal note size and density. The result is a stage that is not only large but is holographic with precise imaging and spatial cues. Stellar instrument separation and a black background give the Fusion tangible layers of width, depth and height.

Comparisons
M-Fidelity SA-50



The SA-50 has long been one of my personal favourites. With 5 BA drivers per side, it has a balanced signature with great end to end extension and superb detail retrieval. SA-50’s bass is still my top pick for an all BA bass – it sounds so natural and carries itself with imposing authority. That said, it can’t bring the same level of impact as the Fusion’s dynamic driver although it does get very close.

The midrange of the SA-50 is more in line with its bass and treble as its whole presentation is very linear across the board. Vocals are more upfront on the Fusion and they’re positioned more forward too – the SA-50’s stage position is further back.

Both iems share a similar treble quality with excellent timbre and airiness. The SA-50’s treble sounds slightly more feathered and the Fusion extends a touch further. When it comes to stage dimensions, the SA-50 is wider but not as deep. Therefore, stereo imaging is stronger on the SA-50 but the Fusion has more clearly defined layers.

Itsfit’s Fusion is the first custom monitor that has challenged the SA-50 for the top position in my collection. Thankfully it’s different enough to compliment the SA-50, rather than having to compete directly with it.

LXear Pluto



The LXear Pluto is a 4BA iem and has a bold and upfront presentation with a strong emphasis on bass. Tonally, it’s much warmer than the Fusion due to the underlying bass colouring the sound from top to bottom. How the Pluto performs really depends on the amount of bass in each individual track. In bass-heavy songs or music, it tends to become congested and stuffy while the Fusion is able to maintain its lightness and separation regardless of the recording.

Both iems have a similarly upfront vocal presentation but the Pluto doesn’t have the same separation or layering ability and as a result, it has a less convincing stage that is surrounded by heavy, rounded bass notes.

It’s a similar situation in the treble too. Even though Pluto’s lower treble is more forward it’s mainly there to compensate for the powerful bass and the stage still ends up being darker than the Fusion.

These have starkly opposing approaches and each one would no doubt appeal to different listeners. The Pluto would be ideal for musicians as a stage monitor or people who want a more upfront performance with a wow factor. The Fusion, on the other hand, has more of what is commonly known as an audiophile tuning that concentrates on details and nuances rather than sheer fun factor.

Empire Ears Bravado



The Empire Ears Bravado is a dual-driver hybrid with one dynamic driver and one balanced armature. Its sound signature is more L-shaped and less mids-forward than the Fusion. Its extra bass presence brings with it more warmth and body. In contrast, the Fusion’s bass is tighter and has better definition but has less overall impact.

Bravado’s midrange sits further behind the bass and goes for more smoothness over absolute clarity. Furthermore, the treble is more laidback and doesn’t have the extreme extension that the Fusion has.

A direct result of the relaxed treble and rounder bass is the Bravado’s smaller stage, although it is still excellent for such a warm iem. The Fusion has more pinpoint imaging thanks to its detailed treble and tighter bass plus clearer air between notes gives it stronger instrument separation.



Conclusion
I have to admit that I was not expecting to be affected in such a manner by the Fusion. While it’s not unheard of for a new brand to enter the market with an excellent product, it is uncommon for one to manifest with such a level of completion. The Itsfit Fusion feels whole in every sense; from the coherency and maturity of its sound to the branding, packaging and build quality.

The Fusion has a golden ratio of bass, midrange and treble that creates the perfect mystic blend. No single IEM is going to please everybody as personal preferences in tuning and musical tastes vary too much but it’s hard to imagine most people not loving the Fusion. Not only does it excel on a technical level but it has a tuning that is lavishly musical and impassioned. With its fun but tight bass, liquid midrange and spectacular treble, it is simply outstanding.

Specifications

• Driver configuration: 1 Magnetostatic driver, 2 Balanced Armature drivers, 1 Electro-dynamic: low
• Freq. Response: 4Hz – 40kHz
• Sensitivity: 98 dB/mW @ 1kHz
• Impedance: 13.1Ω @ 1kHz
• Isolation: -26dB
• Price $950
• Website: https://itsfitlab.com/

I got to try the universal version at their shop in Hanoi last week. They remind me of the 64 Audio U12 Adel but with a more organic/natural sounding bass. Like the U12 these have just a bit too much bass for my taste not that it overwhelms the mids, the bass is just a bit too boosted for me. I prefer the 64 Audio U10 profile. That said, they did sound really great. The mids and highs were nice with nothing missing, the highs were nice and crisp. Back to the bass, it was not bloated nor muddy, I was hearing things from Tony Levin's stick and bass in King Crimson's Discipline album that I had never hear before. The team at Itsfit say the bass can be tuned to match my preference which is good to know. At the price of $950 they are really an amazing deal considering they sound as good or better than items costing much more.