PROS: Linear & Neutralish Signature, Highly Transparent Sound, FIBAE Technology, Very Good Performance for The Price
CONS: Upper-Mids Can Sound a Little Intense, Slightly Subdued Upper Treble
I would like to thank Custom Art for providing the FIBAE 7 IEM free of charge in exchange for a review.
FIBAE 7 is Custom Art’s new flagship sporting a 7xBA configuration. This is not Custom Art’s first FIBAE IEM so I won’t go into the details about it, but let me give you quick background. If you look at the impedance curve of a typical multi-BA IEM, it would not be flat. For reference, single DD IEMs and planar magnetic headphones typically have a flat impedance curve. The problem with IEMs that don’t have a linear impedance is, it can result in impedance mismatch if not used with the right source. The interaction between the Output Impedance (OI) of the source and earphone impedance will result in an altered frequency response if the impedance curve is not flat. So it is highly advisable to use multi-BA IEMs on sources which have low OI.
Now Custom Art’s FIBAE tech, which stands for ‘Flat Impedance Balanced Armature Earphone’ essentially solves this problem. As the name suggests FIBAE IEMs have a flat impedance curve, which helps keep the frequency response unaltered/intact, when used on a source with high OI. While it is fine to use Fibae IEMs with high OI sources, it is still best to avoid those desktop amps with OI higher than 10 Ohms. FIBAE 7 is available in both universal and custom versions for $1300.
Packaging and Contents:
The contents came in a black cardboard box. Inside the cardboard box, you get a pair of FIBAE 7 IEMs paired with Null Audio’s Aerete Cable, a Pelican 1010 case, a compact zipper case, 3 x pairs of silicone tips, 1 pair of bi-flange silicone tips, a cleaning tool, a dehumidifier puck and a welcome booklet. Nothing too fancy, but you get all things that you need to store, carry and maintain your IEM. The highlight other than the IEM itself is the tiny zipper case that is almost the same size as a mint box that you can easily stow in your pocket. It is a bit of tight fit for the FIBAE 7 with the Arete cable, but manageable. I will be referring to the FIBAE 7 as ‘F7’ for the remainder of the review.
Build, Comfort, Isolation and Cable:
The universal F7 is a tiny pear shaped IEM that sits comfortably in my ears. It sits flush enough that I could lie on my sides on a pillow without the IEM pushing against my concha. But depending on your ears the fit could be different. The build quality and finish is excellent. The nozzle of the IEM is long enough and slightly angled to reach my canal and seals securely, resulting in good isolation. I feel necessary to mention that the nozzle has a notch at the end to hold the ear tips in place, something that some manufacturers are still not incorporating in their universal IEMs.
The included Null Audio Aerete cable is a 4-wire design. The cable is neither on the thin and light nor on the thick and heavy side. It has a bit of memory, but is quite flexible. As for as ergonomics, it’s definitely passable, and far from cables like EA’s premium cables or the Dita OSLO. Despite F7 uses a standard 0.78mm socket, I wasn’t able to fit my Effect Audio and Dita OSLO cables. The fit was too tight that I didn’t want to risk bending the pin on the cables.
F7’s sound can be described as neutralish balanced. If you look at its measurement, it sits somewhere between the Harman Target curve and the Diffused Field Target curve, given the slight bass boost and the upper-mid bump. So in my books, it qualifies for being neutral on paper. In practice, it is in the ball park of neutral, and has the tendency to put vocals in the spotlight when the track has one. But it is not to an extent of being vocal-centric because, unlike vocal-centric IEMs, which typically can’t handle a wide variety of genres, F7 is actually quite genre versatile. For reference, Zeus is another IEM popular for its vocals, but it wasn’t great at handling genres like electronic, orchestral and pop. The F7 on-the-other-hand, handles those genres quite well. Another IEM that comes to mind when listening to the F7 is, the Etymotic ER4S. Unlike the ER4S, F7 has a more authoritative and resolving bass, plus a larger head stage with better separation and layering. The overall performance across the board is a step up as well.
The bass on the F7 is slightly enhanced and the warmth from it, helps offset the brightness originating from the 3kHz bump. While it is far from being one note and limp like that of ER4S’ bass, it still carries the bass characteristics of a BA. Simply put, it’s a well done BA bass. Nothing more nothing less. So there is good punch and slam in the mid-bass and the right amount of sub-bass extension and rumbles. This helps provide adequate foundation to the sound, but not draw too much attention to itself. People who prefer a sub-bass centric bass with leaner mid-bass might find the bass a bit on the fuller side.
Despite the signature being even handed and not being mid-centric, there is a slight emphasis in the upper mids, which is what puts the vocals and certain instruments in the spotlight. But the consequence is, in a track where a vocal is already emphasized, it makes the vocals shouty/stressed/intense and can tend to get fatiguing after a while. And on some tracks it can sound unforgiving if the track has a lot of energy in the upper mids. Except for this slight upper-mid emphasis, the midrange as a whole is very linear and carries sufficient body, which results in high level of transparency. So voices and instruments sound clear and correct for the most part.
The transition from the upper mids into the treble and the lower treble is one of the best executions I have heard to date in a multi-BA IEM. This makes cymbals and high notes of violins and pianos sound very accurate. But the roll off into the upper treble happens just a tad early, so sometimes the final overtones of cymbals can sound a bit subdued. But that’s me nitpicking. Upper treble is also a bit toned down, so some may find the sparkle and air a bit inadequate. Overall, it is a gentle treble that causes no harshness.
The presentation is a bit on the forward side than neutral. It isn’t forward to a point of sounding in-your-face, but it does present the vocals with intimacy/immediacy. The stage is quite spacious with good amount of width, which helps the instruments to pan out effortlessly without any congestion. Though the stage might lack some air, it is a clean stage. While its resolution, depth, layering and imaging performance are commendable, the performance is not on the same level as IEMs like the U18t. Where the F7 matches or does better than some of the more expensive flagships is the transparency because of its very linear signature.