Custom Art FIBAE 7 Unlimited (F7U)

The FIBAE 7 Unlimited is the top model from Custom Art, which is based in Poland. Custom Art was founded in 2012 by Piotr Granicki and now has 12 years of experience in the field of IEMs. The first top model was the Harmony 8 in 2014, which was continuously improved to become the Harmony 8.2. At some point, the generation of FIBAE models was introduced, culminating in the FIBAE 7 Unlimited. The name is derived from "Flat Impendance Balanced Armature Earphone" and was the first system in the world to ensure that an IEM always maintains the same frequency response on DAPs and source devices with different output impedance. This eliminates the problem of always experiencing a slightly different sound with different DAPs, as these usually have a slightly different output impedance. The usual range is between 0.1 Ohm and 2 Ohm.




The FIBAE 7U is available as a Universal and Custom IEM. I am testing the Universal here. As the name suggests, the FIBAE 7U is equipped with 7 BA drivers. Two for the bass range, one for the lower mids, two for the upper mids and two top-firing tweeters. You can tell from the size of the IEM that there are no 12 or more drivers on board, which has a positive effect on the weight and, above all, the comfort. The part is so light and comfortable that you forget you're wearing an IEM after a short time. The workmanship is fantastic and the design contributes to a high-quality overall impression. Other designs are also available on request.

The scope of delivery includes a hardshell case from EVA which was specially designed for Custom Art. And finally a case is included that also fulfills the practical part. Because in addition to an IEM, I also want to store my other accessories such as cables and eartips together. Other manufacturers usually provide small round storage boxes made of metal or leather, which offer very little space and you always have to stuff the IEMs with cables into them. Custom Art has solved this better with this case!




In addition to a cleaning brush, silicone eartips in 3 different sizes, a pair of double flange eartips and a warranty card, a high-quality copper cable from Null Audio, namely the Arete model, is also included. You can choose between different connection variants for the cable. I received the 4.4mm Pentaconn version.

With the 7U, Custom Art has taken the feedback from customers and reviewers about the first FIBAE 7 (without Unlimited) to heart and further improved its tuning. The result is more sub bass, a slight reduction in the mids and improved treble through the use of an improved crossover with a specially 3D-printed waveguide. The aim of this model is a neutral tuning that tries to find a good balance between neutrality without sacrificing musicality and fun. And I can say that it has definitely succeeded!

For the test I also use my iBasso DX320 MAX Ti, which I only have to run in low gain with the FIBAE 7U, as the Custom Art IEM with its 12 ohms and 122dB sensitivity is very easy to drive.



With a price of 1500€, the FIBAE 7U is certainly not a cheap IEM, but its sound and technology are similar to those of the U12t and Cadenza 12, making it a lot cheaper than the competition!

The tonality is similar to the U12t when using the M15 module. The U12t has slightly more bass and sounds a little warmer. The Cadenza 12 sounds a little punchier at the bottom thanks to the DD drivers, but doesn't have the same quality as the other two. Overall, the FIBAE 7U is a bright IEM that never sounds too sharp in the treble for me. Of course, the eartips and the cable also play a role here. The SpiralDots fit the FIBAE 7U like a glove in terms of sound and deliver a frequency response that is absolutely coherent. The copper cable supplied also fits the Custom Art very well. I cannot recommend a pure silver cable for this IEM. I briefly tested my Lavricables Grand Line IEM and then went back to the copper cable. It is not necessary to get more out of the soundstage or the resolution with the 7U. It's already great as it is!

The bass range is as good as it can be with BA drivers. There's enough sub bass, the kickbass punches you in the ear nice and dry and crisp and the audibility is really fascinating. A U12t can't quite keep up with that and neither can the Cadenza 12. It also trumps both in terms of speed. I have to get out my Multiverse Mentor, which shows everyone where the hammer hangs in terms of BA bass. The texture and feel of the bass then goes to the Multiverse Mentor, which also uses a BCD to help.

I also really like the mid-range. Voices and acoustic instruments are emphasized with a minimal presence and you almost think the vocals and instruments are playing right in front of you, they are so vividly presented.

The fact that this minimal boost in the mid-range is not distracting at all ensures the wide and deep imaging of the stage. Alongside the bass, this is another highlight of the FIBAE 7U. In terms of instrument separation, it beats the U12t and Cadenza 12 and is only beaten by the Multiverse Mentor, which for me has the most holographic stage imaging in the IEM sector.

The treble has endless resolution. Here it plays along with the really big IEMs. In addition, the treble never tends to be sibilant if you use the right eartips. The high airiness is also a feature that needs to be emphasized.

Overall, I like how this entire tuning seems coherent and in flow with each other. Perhaps the use of fewer drivers in contrast to the U12t and Cadenza 12 also contributes to this overall presentation. According to the motto "Less is more!".

My own collection of IEMs also consists primarily of IEMs with umpteen drivers. I have always lost sight of one attribute and that is comfort. Now that I have an S15 and now also a FIBAE 7U as a comparison to the IEMs with 12 drivers, this significantly better comfort is of course immediately noticeable. And if you really listen all day with IEMs, this is something you should always keep in mind. For me, however, I usually don't listen with IEMs when I'm out and about, but rather enjoy 1-2 albums at a time at home. The transparent fit of the IEMs doesn't play the biggest role here.

For 1500€, Custom Art has launched an outstanding neutral IEM that doesn't have to hide from higher-priced models. I like its sound even better than a U12t or Cadenza 12 and it is therefore my new reference in the field of neutral IEMs. I can warmly recommend the FIBAE 7U to audiophiles who are looking for an acoustic magnifying glass that teases everything out of a recording without neglecting musicality and fun. In the current price structure of IEMs and in view of its technical capabilities, I can even call it a bargain!

This is a review of Poland based Iem manufacturer Customart’s latest TOTL product, F7U ( Fibae 7 Ultimate) which according to Customart is a fully reworked F7 for more musicality and engagement. I haven’t heard their previous model F7, so my comparisons would be based on Customart’s highly regarded old TOTL iem Harmony 8.2.

Please note I am just a listener not a reviewer but will try my best to explain my impressions.

I’ve spend a week with the F7U and paired it with both Sony WM1A and Cayin N6ii with R01 module. Most of my listening was done on N6ii. In the first listen itself, I realize F7U is a huge upgrade over my previous Customart Harmony 8.2 universal. This is my first ciem and boy I feel like ciem is the way to go, fit and isolation is excellent!



Opting for a ciem was a challenge. I had to trust Piotr’s tuning skills and place the order blindly, which was pretty much taking a chance because I haven’t experienced any newer Customart iems. My previous Harmony 8.2 was released back in 2016, so it’s been a while, and since then Piotr was quite busy releasing a bunch of iems on the Fibae lineup.

Initially I was just going to reshell my trusty H8.2 to customs, but going through Customart website and headfi forums, my plans changed and I was looking for an upgrade to one of the newer CA Fibae models. I was not specifically looking for any particular model, I wanted something that mainly handles extreme metal music very well but without sounding too analytical, I wanted some musicality. Piotr was very helpful in choosing the right iem from their entire lineup. After months of back and forth with Kamil and Piotr I went ahead with their latest release F7U.

I have to mention how easy it is to work with them, we exchanged close to 100 emails over the course of last four months lol (this is the most I’ve spend on an iem and that too going blindly so well..) they both were very patient and understanding, never pushed me for a quick purchase. Even while going through the designing phase, they provided me with a lot of options to choose from with the face plate. I was very particular about the wood grain and texture and they had to change it couple of times but never hesitated and made sure I got the best result.



Sound wise F7U has very natural timbre, tonality is not as neutral as H8.2, it’s a more fun and engaging sound with a good balance overall. F7U has boosted low end with good body and presence. This was one of the first things that stood out for me, I am no basshead but tried some bass heavy music and wow, the impact can be felt! There’s day and night difference here when compared to H8.2 and at times the mid bass felt a bit too much for my personal taste with bass heavy music. This genre of music is not my cup of tea but for my library which is mostly metal/rock the impact and speed is perfect. I’d say the bass here is a perfect balance between impact and speed. Its punchy and well controlled. F7U easily kept up with blast beats no problem. It’s not as fast as H8.2, but I am enjoying the extra weight on the mid bass here. Kick drums have solid impact on a track like 'Slayer - South of heaven' Dave Lombardo’s snare, particularly skin tone sounded pretty accurate as well, something you typically experience on a DD. 'Negative Plane - The Pact' is one of my favorite recent release, I really enjoyed following the bass guitar through out the record, it’s got a nice weight. Most of metal music doesn’t go all the way down to sub bass, but with Psychill music like Hinkstep, Shpongle.. I can feel the deep low rumble. There’s plenty of sub bass here for my ears. I prefer the bass on F7U over Sony IERM9 which can be a bit too much at times for my taste.

Mids are excellent, there’s a touch of warmth on lower mids which gives vocals nice weight and body to excellent singers like Peter Steele (Type O Negative) or Mike Patton (Faith No More). I am sensitive to upper mid peaks so I did a sibilance test with Rob Halford’s (Judas Priest) screams on tracks like 'Painkiller' or 'Screaming for vengeance' and Geddy Lee’s (Rush) 'Cygnus-X1' where he hits the highest note at the end of the track or the masterpiece '2112' none of these tracks sounded harsh/shouty, in-fact It sounded quite smooth even on poorly mastered 80/90s metal records. Many of these early extreme metal records are produced with treble forward sound which ruins the listening experience especially on bright iem’s but with F7U’s non fatiguing sound I was able to enjoy many of my favorite records. Heck, I could even sit through some late 80’s early 90’s lo-fi black metal which is an achievement if you are aware of early black metal production quality. As much as I love this 1st/2nd wave of black metal they had the shittiest production, every band back then competed to make the worst sounding record. I really love how guitar cuts through the mix on F7U, listening to chunky down tuned old school death metal riffs from bands like Entombed, Dismember to Gatecreeper sound excellent! (BOSS HM-2 fans you know what I mean.)

Highs are more pronounced compared to H8.2, there’s more energy but it’s not overdone. It is more detailed without sounding bright and this was very important for me. I am very sensitive to bright sound and F7U doesn’t come across as a bright set (I have to disagree with the headfonia review). It sounds very smooth and non fatiguing with excellent micro details. I don’t think it’s easy to achieve this kinda sound, kudos to Piotr.



Separation is excellent, even with a busy track like 'With all disrespect - Cattle Decapitation' I was able to hear everything in the mix, even the bass guitar in between all of the chaos. There’s good sense of space in between instruments, especially on well mastered tracks which is very evident coming from H8.2.

Soundstage and Imaging are much better here. Certain records that showcased F7U’s excellent stage/imaging capabilities were Roger waters - Amused to death, Supertramp - Crime of the Century and Dead can Dance - Spiritchaser. I felt a very 3D-like presentation with these records. It’s not the most wide soundstage I’ve heard, but F7U is a huge upgrade over H8.2 and my other set, Shuoer EJ07.



F7U was able to handle everything in my library from extreme metal to world music leaving me with a smile every time. I had a few goosebump moments as well. Imo Customart F7U is a winner and the best I’ve heard till date.