Closer Examination

FiiO made a big deal about the customization options with the FH5s, which begin with the cable itself. Specifications aren't much to complain about. This is a braided litz cable with four strands of 120-core silver-plated copper, with the use of monocrystalline copper for larger conductor size and potentially lower resistance. On the source side comes a 3.5 mm TRS plug to begin with, which is on a large aluminium housing with a knurled finish on the end for grip and a polished surface that has the "born for music" slogan etched in. The grippy surface helps unscrew the connector and pull it off, revealing four pins inside that go into the equivalent replacement plug should you now want to go to, say, a 4.4 mm Pentaconn connector for a balanced cable. This is a nice way to get around using adapters, but ultimately hurts the electrical behavior by adding resistance at the junction, negating all the good from the core design.


The cable uses a polyurathane (PU) insulation rather than the polyvinyl chloride (PVC) that cheaper cables do, with many psychoacoustic beliefs about PU being better than PVC for headphone and IEM cables. I personally have yet to really encounter that, but the insulation gets a silver finish that looks really nice in person. The four strands split into two past the marked splitter with the FiiO logo on it, and a cable minder helps contain the two splits where you want another fixed point closer to your head. A thicker, transparent plastic sheathing comes up closer to the ends, where we see it formed similar to memory wiring for the cable to naturally fit around and over your ears. The physical connection to the ear buds is an expanded MMCX connector on each end, housed inside a see-through plug case with blue and red rings to denote the left and right channels. I would have preferred 2-pin connectors myself, but there is still a use case for MMCX paired with a removal tool compared to some 2-pin cables that can bend the pins easily. All the plugs, including the replacement ones, are gold-plated for oxidation resistance.


We get to the main event now, and FiiO managed to surprise me with the design. These are not closed IEMs as you would expect by default, instead adopting what the company calls a semi open-back design. FiiO is quite proud of the shell design, going as far as dedicating an entire YouTube video to it. The bigger dedication, at least to me, was spending the resources on a new CNC tool to get the triple-layer faceplate design FiiO calls its third-generation ergonomic curve. Using a magnalium (magnesium/aluminium alloy) composition, it is sturdy and light (~8.8 g each) while allowing the smoother curves. FiiO says the material composition also blocks off unwanted harmonic resonances, but that is to be expected of any established material design used for IEMs.

The exterior layer is effectively the faceplate and not completely closed off. This allows for a look at the gold-colored secondary layer with an air-guide mesh akin to an open-back set of headphones, which is what the semi-open-back design refers to, which FiiO calls the dragonscale design. The black and gold colors combine nicely, if I may say so myself, although I think the silver and gold will do even better, especially paired with the silver-colored cable. The gold is also more of a copper than the color you may think of and continues on a trim on the outside as well. The MMCX connector expanding outwards from the housing makes for a weird-looking protrusion when examined by itself, but helps with the installation and removal of the cable a lot, especially with FiiO's provided tool, to where the benefits outweigh subjective appearances.

There is a large cutout on the side we will examine below, and no dedicated vents beyond the several already seen, which simulations showed FiiO are good for balanced air pressure throughout. L and R markings on the inner surface going to the ear confirm which one goes to which ear, though the ergonomic design makes it obvious enough. At the bottom is a relatively cylindrical nozzle with a bore size of ~5 mm, where we see a mesh filter to keep contaminants out. A small notch in the nozzle holds ear tips in place, and I would have liked this widened slightly since some of the included ear tips were not very snug over time.


The large cutout on the side of each ear bud is to access three dip switches small enough to where the tapered end of the cleaning brush tool comes in handy. By default, all three switches are turned to the off position (switch at the bottom), with B, M, and T markings underneath standing for bass, mids, and treble respectively. These tuning switches are thus to customize the already tuned IEMs to cater to those prioritizing the lows, mids, or highs by simply turning on the respective switch for an emphasized response in said region. All three turned off is balanced mode thus, and this hardware EQ tuning should work better than software equalization if FiiO has done the job well. Note that turning on more than one switch at the same time is not recommended since it can make the tuning deviate dramatically from the base curve.


Two size M silicone tips come pre-installed out of the box, and I personally think they are terrible. They dry out easily and do not conform to a fit inside the ear canals over time—I don't see a reason to use them since FiiO includes application-specific ear tips already. The double-flanged ones also work much better as general-purpose tips, although your mileage may vary. In fact, I would say the foam tips are even better, but of course with the usual potential caveats of increased wear, extreme isolation, and skin incompatibility. Once you have finalized the ear tips of your choice, carefully plug the cable in by pressing in the MMCX connectors with both ends touching each other and the housing not flexing or bending anywhere. Matching the channels is key as well, but the MMCX connectors may be rotated 360° around the connecting point, so you can orient the cable as best as possible around and over the ears. The provided replacement plugs are also handy for source-based customization, and I typically stuck with the 3.5 mm TRS plug for my testing. I know there are many who prefer using IEMs throughout, but I like using over-ear headphones when sitting down and IEMs/TWS earbuds on the go. In the absence of other options at this time, I hence chose to use them primarily with my trusty FiiO E17, which of course needs to be shown for the family photo above.