CustomArt FIBAE 7 Unlimited


FIBAE 7 (Universal).

CustomArt FIBAE 7U vs FIBAE 7 2

They both have very different sounding signatures and upgradability will depend on what you personally like and prefer rather than there being an outright winner. Since I still love the original F7, I think it would’ve been great if CustomArt kept both F7 and F7U in their stable as options for people to choose based on the kind of signature they preferred.

Comparing the universal versions of both, where the original F7 was a bass boosted Diffuse Field target inspired IEM with warmer lower-treble and airy upper-treble, the F7U instead is a fuller and airier take on the Harman Target. The first thing that struck me was F7U’s upper-midrange pinna gain being significantly lower than F7’s. F7U’s bass boost is also around 2-3dBs more than F7’s, so F7U’s bass overall comes across stronger and fuller. F7U’s midrange overall sounds fuller than F7 in comparison because of lesser pinna gain. F7U has more treble quantity balanced with its warmer lower-end FR, with airy upper-treble character that is a bit like 64 Audio’s Tia driver style of upper-treble tuning. F7 is slightly darker in the treble area in comparison. Overall, F7U has a more fun-tuned W-shaped, slightly romantic, fuller signature whereas F7 has a forward upper-midrange based, much cleaner and leaner signature.

When it comes to technical performance, F7’s soundstage is slightly deeper but F7U’s width boundaries are a touch wider. F7U definitely has the more spaced out soundstage presentation with better separation between instruments left to right. Clarity is on par but because instruments in F7 are much more forward because of more pinna gain, they seem more defined in the F7. But at the same time, F7 can also come across shouty/peaky to people who like their pinna gain served on the easier side of the Harman or Diffuse Field target. Those people will definitely prefer the F7U over the F7 as it is a much easier listen. When it comes to perception of resolution while keeping the starkly different sounding signatures of both in mind, they are actually more or less on par once your ears have adjusted to their signatures properly. At times, one can have varied perceptions in quick back to back comparisons based on the IEM the ears have adapted to more, especially with IEMs that are tuned so differently.

Regardless, F7U takes the cake when it comes to a fuller W-shaped romantic take on reference signature and F7 when it comes to a cleaner, more reference sound signature. With that said, F7U is definitely more than capable of filling in F7’s shoes as CustomArt’s new flagship. If I had to chose with a gun to my head, I’d probably go for the F7U today. Can’t say about tomorrow. Lol!

Custom Art F7U Universal + Cable

Polish Bros Inc.

Having reviewed and being acquainted with 3 very cool Polish brands – CustomArt, Lime Ears and Craft Ears, I thought a Polish Bros Inc. comparisons section will be very interesting since they all have IEMs in this price range. BTW, Polish Bros Inc. isn’t a real thing. It’s just what I call these 3 brands collectively in my circle for fun. Ha!

Lime Ears Aether R (Universal).

CustomArt FIBAE 7U vs Lime Ears Aether R (Bass ON)

They are very different sounding signatures. I’ve used Aether R with the Bass switch ON in the comparison here because it’s a bit bright for me with it off. Aether R is a slightly bass boosted Diffuse Field-ish IEM. It is much leaner and brighter than the F7U with a very clean and open soundstage and forward instrument definition because of more pinna gain. F7U on the other hand has more bass presence – slam as well as rumble, plus fuller lower-midrange presentation which results in fuller and warmer instrument body. Aether R is significantly brighter in the 5k-8kHz lower-treble region whereas F7U is airier in upper-treble with better upper-end extension. Aether R is a detail oriented, clinical IEM whereas F7U is a coloured, fun take on a reference signature. Aether R has the cleaner and deeper soundstage but F7U’s width boundaries are wider. Aether R might come off as the one with better micro-detail retrieval out of the two at first because of its clinical signature but it is the F7U that has better clarity, instrument realism, resolution as well as layering along with a more versatile signature.

Lime Ears Pneuma (Universal).

CustomArt F7U Universal vs Lime Ears Pneuma Universal

Starting with bass, even with Pneuma’s bass switch OFF, its bass shelf is ever so slightly more than F7U but because F7U has better separation, especially left to right, it’s actually the F7U whose rumble and slam is heard clearer and better. Both have a slightly fuller lower-midrange presentation and similarly forward upper-midrange presentation but F7U has a more accurate pinna gain peak. Pneuma is brighter in lower-treble but then starts a gradual decline past 10kHz. That brightness in lower-treble adds on greatly to instrument presence but also a bit of glare with some brighter songs. F7U is much airier up top with a prominent 17kHz peak and because of that, its upper-treble peak always stands out in an A/B comparison until the ears adapt to it. Pneuma actually comes across more natural right off the bat until the ears adapt to F7U’s 17kHz peak. F7U does have a mid-treble dip but picks up from around 12.5kHz and has better upper-end extension of the two. Both have good macro detail retrieval but F7U has better micro detail retrieval as well as better separation and layering, primarily because of better upper-end extension. Pneuma is no slouch but falls a bit behind in that aspect. F7U’s airiness and upper-end extension also helps it have a wider and more open soundstage. Pneuma has sharper instrument presence but its soundstage width feels slightly closed in compared to F7U, mainly because of warmer upper-treble tuning.

Craft Ears SIX (CIEM).

CustomArt F7U CIEM vs Craft Ears SIX CIEM

Even though F7U and SIX are both coloured, fun takes on the Harman target, they are very different sounding IEMs otherwise. SIX has a leaner, more detail oriented tuning whereas F7U has a fuller, more romantic tuning in comparison, with airy upper-treble being the common element between the two. Breaking it down, SIX’s RASEN bass has its focus towards sub-bass rumble whereas F7U’s bass has its focus more on the mid-bass boom and punch. Both have around 9db of pinna gain but F7U has a fuller lower-midrange presentation whereas SIX’s upper-midrange sounds more forward with stronger instrument definition. When it comes to treble, SIX comes off much brighter in comparison and its 16kHz also comes off more prominently compared to the F7U’s 15kHz upper-treble peak, primarily because F7U’s fuller signature adds more warmth. Both create a nice soundstage, with SIX having a more open, slightly diffused out presentation and F7U having a slightly fuller presentation because of it lower-end warmth but one with better pin-point precise imaging. Both are equally good at macro-details but SIX jumps slightly ahead with better micro-detail retrieval because of its brighter and leaner tuning, which is a double edged sword as it is not as versatile with brighter songs. F7U is no slouch and has excellent detail retrieval for its price while maintaining a signature that is the more romantically musical out of the two.

Custom Art F7U CIEM + Cable

Comparisons with some $2000 benchmarks.

64 Audio U12t (Universal).

CustomArt FIBAE 7U vs 64 Audio U12t (M15)

With the M15 Apex module, U12t has around 2dB more bass shelf than F7U and more sub-bass rumble and mid-bass boom as a result. But F7U has better left to right separation which results in better separated bass in the centre. F7U’s bass has sharper attack and quicker decay whereas U12t’s is softer as well as more boomy and gooey. Even though F7U has a fuller lower-midrange presentation than neutral, U12t has even more fullness because of more gain in the 400-1kHz region. Both have a forward upper-midrange presentation but F7U has a more natural pinna gain peak whereas U12t has a dippy-boosty upper-midrange with 2 primary peaks – one around 2.2kHz and the other at 5kHz. U12t has slightly more presence in the 5k-7kHz region where F7U has a dip, but then F7U is brighter in the 8k-10kHz region. Both are dipped in mid-treble and then have a significant upper-treble boost – F7U at 17kHz and U12t at 18kHz. Both have a very nice soundstage but I’ll have to give it to the F7U for better left to right separation as well as depth layering. Both have good detail retrieval but F7U makes for a more exciting and fun listen for me personally because of its slightly brighter and airier tuning. The U12t on the other hand can come across a bit too warm because of warmer 7.5k-17.5kHz region.

Softears RS10 (Universal).

CustomArt FIBAE 7U vs Softears RS10

RS10 is a reference tuned IEM and follows its sister company Moondrop’s VDSF target, which is based on the Harman Target. F7U has a slightly bigger bass shelf as well as fuller lower-midrange presentation. Both have a forward upper-midrange presentation because of similar amount of pinna gain. They’re similarly bright in lower-treble but with peaks at different frequencies. RS10’s treble is more linear and natural while the F7U is brighter post 10kHz as well as airier up-top, which makes it sound more W-shaped compared to the RS10. RS10 does come across more neutral with more accurate and natural tonality and timbre whereas F7U sounds like a fun, coloured take on the same. RS10 has a very natural soundstage with good width and depth but F7U has a wider and deeper soundstage, with a more holographic experience. RS10 has stronger instrument definition but F7U has better left to right separation as well as depth layering. Both are really good at micro-detail retrieval but F7U will probably come across a bit better to many in this area because of the brighter and airier signature.


CustomArt definitely has a winner in the F7U. Even though the original F7 was one of my favourite IEMs in its price segment – one that had a particularly nice soundstage and really good technical performance, I could definitely see it coming across a bit lean and shouty to people who preferred a fuller lower-midrange presentation and pinna gain on the easier side. That’s exactly what the F7U solves. F7U adds a V-shaped character to the original F7 by boosting a bit of bass, pulling down the pinna gain by a couple of decibels and then boosting the treble, resulting in a W-shaped signature with an exciting tuning and more than capable technical performance for its asking price. It especially does really well in musicality and has a very high engagement factor for me personally. With a very comfortable UIEM fit, one of the best CIEM fits I’ve had the pleasure of trying and some of the best in class artwork and designs on offer, it just makes recommending the CustomArt FIBAE 7 Unlimited even easier. Just the stock design itself is an eye catching standout in the IEM world but you can take it further and go berserk with custom artwork and design, and I’m sure CustomArt will be able to execute it to total satisfaction. They surely did so with my CIEM. Definitely give the FIBAE 7 Unlimited a shot if you’re looking for an IEM in the $1000-2000 price segment!

Gear used for testing and review.

  • DAPs – iBasso DX240 & DX170 | Lotoo PAW6000
  • Laptop – Apple Macbook Pro 15″
  • Phone – OnePlus 7 Pro

Artists I like and listen to.

  • Rock – Foo Fighters, Linkin Park, Switchfoot, Imagine Dragons, Daughtry, Green Day, MuteMath, X Ambassadors, Dave Matthews Band, Vertical Horizon, Our Lady Peace, Lifehouse, Fall Out Boy, Breaking Benjamin, Muse, ACDC, Audioslave, Rage Against the Machine, Biffy Clyro, I Am Giant, Normandie, Paramore, Slash & Guns N Roses, 3 Doors Down.
  • Pop Rock – John Mayer, Coldplay, Paul McCartney, James Bay, Hunter Hayes, Niall Horan, Keith Urban, The Bros Landreth, Bryan Adams.
  • Progressive Rock/Metal – Porcupine Tree/Steven Wilson, Karnivool, Tool, Dead Letter Circus, Periphery, Lamb of God.
  • Pop/Soft Rock – Ed Sheeran, Adele, Taylor Swift, OneRepublic, The Script, Gavin James, Magic Man, Maroon 5, Bruno Mars, Charlie Puth, Dua Lipa, The Weeknd, Oasis, Panic! At the Disco, TwentyOne Pilots.
  • EDM – Chainsmokers, Zedd.

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