FiiO FH15

If Forrest Gump were a fan of In-ear Monitors (IEM), he would say, “Life is like an IEM from the FH line of FiiO. You never know what you’re going to get.”

Whilst the FD line (FiiO’s Dynamic Driver IEMs) is predictable with a Harman-inspired tuning, and a varying degree of a treble peak at 5kHz, the FH line (FiiO’s Hybrid IEMs) is pretty much a wildcard. There seems to be no pre-defined target for this line, and thanks to the flexibility of a hybrid multi-driver configuration, FH IEMs can be anything. Sometimes they surprise you in a good way (FH9), sometimes they are honky (FH3), and sometimes they are just downright … strange (FH5s).

What can you expect from the latest addition to the FH line, the FH15? Let’s find out.

Forewords​

• This unit is a review sample from FiiO (thank you!) FH15 retails for USD $230. You can find them at your local distributor or official FiiO store on Aliexpress.
• You should treat this review as the subjective impressions of an audio geek rather than an “objective truth” about the IEM. Your experience with any IEM would change depending on your DAC/AMP, music library, ear tips, and listening volume.
• I rate IEMs by A/B testing them against a few benchmark IEMs, regardless of price point. This approach ensures the consistency of the ratings in my ranking list. It means that if two IEMs score the same, they perform more or less similar.
• I believe that great IEMs are the ones that can achieve multiple difficult things simultaneously: (1) high resolution (meaning lines of music are crisp, clear, easy to follow and full of texture), (2) 3D soundstage with a strong sense of depth, (3) bold and natural bass with a physical rumble, (4) natural timbre, (5) relaxing and comfortable tonality.
• Ranking list and measurement database are on my IEM review blog.

Specs​

• Driver: 3BA (Knowles ED for Mid, Knowles RAD for Treble) + 1 DD (10mm carbon-based diaphragm)
• Connector Type: MMCX
• Impedance: 16ohm@1kHz
• Sensitivity: 112dB/mW@1kHz
• Gimmick: Interchangeable nozzles for changing tonality

Non-sound Aspects​

Ok, first thing first. FH15 is not the new flagship of Fiio’s FH line (that position is still FH9). It is the continuation of the FH5 line and the direct update of the FH5s model. Let me explain the organised chaos of FiiO’s product line:

• “FH” indicates FiiO’s Hybrid IEMs, meaning IEMs with a combination of balanced armature (BA) drivers and dynamic drivers (DD). If you are unfamiliar with “drivers”, they are simply speakers. BA are the tiny ones used in hearing aid devices. DD is the mini version of the loudspeakers.
• “1” indicates the first generation that uses the new naming scheme (meaning the previous FH5 and FH5s should be labelled as FH05 and FH05s if we want 100% consistency)
• “5” indicates that the current product is in the middle of the FH line. For your information, “1” and “3” are for the lower end, the “7” label is for the upper end, and “9” is for the top of the line.

(How do I know all of these? Because I have no life, of course)



As usual, FH15 comes in a thick cardboard box decorated with schematic diagrams and holographic logos. No anime waifu (yet).



Inside the box, you are welcomed with the usual two-layer presentation. The IEM sits on the top layer. The bottom layer is reserved for accessories.



As usual, accessories are both generous and practical. You have a box of ear tips plus a complete set of the new HS18 tips, which I adore. You are also provided with a cleaning brush, a new and more practical MMCX tool for disconnecting the cable, and additional nozzles for adjusting the tuning of FH15.

The cable is a departure from the usual 8-strand cable. At first, I was disappointed, from an aesthetic point of view, that it has only 2 strands. However, it works great in practice, so I no longer mind it. The cable is terminated with an upgraded interchangeable plug that debuts with FF5. The new interchangeable plug system looks the same as the old one. Still, replacing the plugs is easier than the previous version.



The ear tips collection of FH15 is extensive. You should try all of them and see which one works best for you since they all sound different. I choose HS18 tips, as they are the most comfortable, and they tighten up the bass response of FH15, making the sound generally nicer.



Let’s talk about the earpieces themselves. They have an old-school shape that is quite rare nowadays. Think of the famous Shure SE215 and Westone universal IEMs with modern nozzles rather than thin and long tubes.

The earpieces themselves are small but relatively thick. They have gold trims similar to the OG FH5. The car-like patterns on the faceplates of the FH5 have been replaced by a “dragon scales” design. I’m unsure about “dragon scales”, but the FH15 faceplates remind me of dragon eggs in Harry Potter or Game of Thrones. I was also a bit worried that the semi-open design of FH5s was gone. Luckily, the soundstage of FH15 is still formidable.



Before we move on, let’s quickly touch on the fit. The earpieces themselves are comfortable. You are unlikely to have comfort issues unless you try to deep-fit these, like wearing a pair of Shure or Westone. Interestingly, it is very tempting to deep fit, given how close to the conchas the earpiece can sit.

How it soundsPermalink​

Sources for listening tests:

• Fiio K7 (for all A/B tests)
• Shanling M6 Ultra
• Hidizs S9 Pro

Local FLAC files ripped from CDs or bought from Qobuz were used for most casual listening and A/B tests. My playlist for A/B tests can be found on Apple Music here.

Tonality and Timbre: 3/5 - Average​

Frequency response of FH15. Measurements were done with an IEC-711-compliant coupler and might only be compared with other measurements from this same coupler. Visit my graph database for more comparisons.



FH15 is a bass-focused IEM. But FiiO has executed this “fun” tonality with finesse and restraint. As a result, you can have an above-average amount of bass without sacrificing the naturalness of voices and instruments. At the same time, FH15 is never harsh or sibilance because FiiO controlled the bass boost well and thus did not need to increase the treble to compensate. The result is a thumpy sound signature with an open, natural-sounding midrange and gentle treble. It’s hard to hate the signature, but there are points to improve.

Let’s talk about the positive aspects.

Firstly, the ear-gain region is finally done correctly. Gone is the unfortunate “hump” at 1.5kHz from FH3 and FH5s that makes vocals and instruments honky, nasally. FH15 opts for a smooth, gentle raise from 1kHz, peaking at around 2.5kHz. The ear gain is only about 8dB rather than the usual 10-12dB used by Moondrop and Harman-targeted IEMs. It means that vocals and instruments are still loud and clear, but they do not get too loud to the point of “shouting” to your face. If you find modern IEMs too shouty, you might like FH15’s tuning.

Secondly, the infamous 5kHz peak that forms the “cat ear” tuning of FiiO does not exist on FH15. As a result, the attack side of musical notes, such as the pluck of a guitar string, does not feel too edgy and piercing. The subdued 6kHz region further smoothens the treble response of FH15, removing most sibilance and harshness. Of course, this tuning choice is a double-edged sword. I’ll discuss its negative aspects later.

Finally, the bass shelf is big and bold yet natural. FH15 has a sub-bass-focused shelf. It means that the bass goes up and up until 20Hz rather than peaking at 150Hz (mid-bass) and rolls off. When the bass drops, the sub-bass energy helps FH15 create a physical rumble in your throat and chest. For instance, when I listen to Skyrim’s main theme Dragonborn, I can feel the rumble with every beat of the war drums. The “boom boom” sound is not neglected either, unlike some other sub-bass-focused IEMs like Monarch II. With FH15, you hear the boom, and you feel it.



Let’s talk about some negative aspects.

Firstly, the treble. Yes, FH15 plays a bit too safe. Whilst the lower and mid-treble, up to around 8kHz, is subdued but still alright, I don’t quite appreciate the steep rolls off after 8kHz. One of the issues is that this tuning robs FH15 of some micro-details, particularly reverbs and decays, the sense of sound bouncing around the recording venue. This issue impacts older classical recordings the most because it hides a layer of information (and enjoyment) from the listener.

Secondly, FH15 tilt too far in the warmth and dark tuning. Whilst the graph shows a relatively clean bass shelf, in practice, the bass of FH15 “bleeds” into the midrange more than expected. Let me elaborate with an example: the One Winged Angel Themeperformed by Game Music Collective. FH15 renders the “boom boom” of the double bass quite loud. Moreover, the “boom” hangs around in the music too long, giving the whole orchestra a sense of “stuffiness”. When I swapped to the Aria (already a warm IEM), I breathed out with relief as if the windows of a closed and stuffy room had been opened.

Thirdly, the timbre of the instruments and vocals of FH15 is somewhat off. The problem is not too apparent with thumping commercial music or large orchestral pieces. The timbre problem appears with sparse music, such as the Chaconne in Bach’s Violin Partita No. 2 performed by James Ehnes, where there is nothing more besides the main instrument and the reverb of the room.

Simply put, the violin sounds boxy, as if it has too much “boom” in the lower end and high notes are muffled rather than being freely projected to the room. The sense of micro-dynamic, the subtle variation in volume, is also unimpressive. I can’t say whether these issues are due to the subdued treble or the “BA timbre”, but I don’t want to listen to Bach’s sonatas and partitas with FH15.

Conclusion: 3/5 - Average/Acceptable. FH15 is not fatiguing and sounds relatively correct most of the time. If you don’t listen to much acoustic music, you might not find any alarming problems with FH15.

Tuning filtersPermalink​

FH15 is packed with 3 tuning filters that you can screw onto the nozzles to modify the treble response. The treble nozzles, which FH15 uses by default, contain only a metal mesh to protect the internals from dust and debris. The balanced nozzles have acoustic filters to tame the treble. The bass nozzles include thicker filters to further reduce the treble.

Do they work? Yes, definitely. And if you combine them with the provided ear tips, you can have many different tunings.

However, I would argue that only one combination works if you want the most clarity, soundstage, and details from FH15: treble filter with HS18 ear tips. The balanced and bass filters tilt the tonal balance too far toward a warm and dark signature. Music notes become too thick. Details start to be masked. The soundstage shrinks and becomes congested.

Resolution, Detail, Separation: 4/5 - Good​

Resolution is a fascinating subject due to the difficulty of pinning what it really is. To me, “resolution” can be separated into “macro” and “micro” levels. The “macro resolution” is synonymous with instrument separation. In general, if note attacks are very crisp and precise, musical instruments in a song would be distinctive even when they overlap on the soundstage. The “micro resolution” dictates how many details you can hear at the note tails. Many IEMs are good at macro- but mediocre at micro-resolution. A few are vice versa.

The macro-resolution of FH15 falls squarely at, or even slightly above, the “good” level, represented by the venerable Blessing 2.

Let’s take the One Winged Angel Theme performed by Game Music Collective as an example for analysing. At a glance, FH15 seems to be at Aria level (3/5 - Average) rather than Blessing 2. This impression is due to the boominess of the double bass and timpani drums. However, back-to-back A/B tests made it clear that FH15 renders instruments with more clarity and more separation than Aria, even when FH15 was held back by the boominess.

Similar observations can be made when comparing FH15 and Blessing 2. At a glance, Blessing 2 feels clearer. In A/B tests, they are on the same level regarding how they highlight and separate overlapping instruments in complex musical phrases. Again, FH15 does so whilst being handicapped by the boomy bass.

The micro-resolution of FH15 is slightly below the “good” level held by Blessing 2.

Let’s take the beautiful Rasputin cover by AURORA as an example. Blessing 2 highlights AURORA’s vocal in the mix and brings all the nuances, the “breaths”, to the surface. On the other hand, FH15 adds a slight warmth to AURORA’s voice, pushes her back to the mix, and lays a “veil” over the fine details. Don’t get me wrong, the details are there, but you need to look for it harder than with Blessing 2. However, FH15 is better than Blessing 2 at separation, allowing me to follow individual instruments and the backup vocals easier.



I did some A/B tests of the FH15 against Andromeda 2020 and the EA Gaea for fun. The mid-fi IEM managed to put up a decent fight against Andromeda but ultimately lost out in the crispness and nuance in the treble and the separation of instruments. And it should be noted that Andromeda is not an outstanding performer regarding resolution. Against the detail-focused Gaea, FH15 is not even in the same postcode.

Conclusion: 4/5 - Good.

Percussion Rendering: 4/5 - Good​

Percussion and bass rendering reflect how well the tuning and technical performance of an IEM work together to recreate realistic sound of drum sets and bass instruments. Good drum hits have a crisp attack (controlled by frequencies from 4kHz to 6kHz), full body (midbass frequencies around 200Hz), and physical sensation (sub-bass frequencies around 50Hz). Good technical performance (“fast” driver) ensures that bass notes can be loud yet detailed. IEMs that cannot control bass very well tend to reduce the bass’ loudness to prevent muddiness.



A reader recently asked me whether the ancient Final Audio E5000 is still a competitive bass cannon in 2023. That’s when I realised a well-done dark, bassy, gigabass IEM is still a rare breed.

FH15 can change that.

As I alluded to above, FH15 has a very potent bass response. For instance, the war drums in Skyrim’s main theme Dragonbornproduce noticeable pressure and rumble at every beat. The good part is you don’t lose much clarity and details to enjoy that bass. You don’t need a beefy source like you do with E5000.

Let’s listen to Eye of The Tiger and discuss how FH15 renders the rest of a rock band. Firstly, the separation between the kick drum and bass guitar is excellent. I can follow the bass line of the guitar easily whilst feeling the solid and deep punches of the kick. Snare drums feel tight and snappy. Drum rolls sound great. The low and mid-frequencies of the band are good.

However, I think the treble is a bit too subdued. For instance, cymbals and hi-hats are barely present in the mix. I can hear their faint ticking sound, but their nuances are lost. Is it a problem? It depends on how much you like (and tolerate) cymbals and hi-hats. If you listen to harsh music for hours, the subdued treble response may be a blessing.

Conclusion: 4/5 - Good.

Stereo Imaging (Soundstage): 5/5 - Excellent​

Stereo imaging or “soundstage” is a psychoacoustic illusion that different recording elements appear at various locations inside and around your head. Your brain creates based on the cues in the recording, which are enhanced or diminished by your IEMs, DAC, and amplifier. Some IEMs present a wide but flat soundstage. Some show a “3D” soundstage with layering, depth, and height. In rare cases, with some specific songs, some IEMs can trick you into thinking that the sound comes from the environment (a.k.a., “holographic”)

If there is one bright spot in FH15’s performance, it’s the soundstage imaging.

Take the organised chaos G.O.A.T. by Polyphia as an example. FH15 projects a large soundstage that often seems just outside my ears and around my head. Within this stage, instruments are arranged in layers from closer to further away rather than a blob of a flat plane. This presentation immediately puts FH15 above the “good” level, represented by Blessing 2.

Does FH15 reach the elusive 5/5 soundstage imaging? Let’s take the Andromeda 2020 out for an A/B test and find out. I found that both IEMs are nearly identical regarding the 3D placement of instruments. Both present a strong, distinct centre image with complex guitar and drums right in the centre and the ambience thrown far to the background, both the sides and in front of me. This presentation is highlighted clearly around 1:04.

The Andromeda is noticeably crisper across the frequency range, especially the treble and the airy ambience in the background. As a result, it has the upper hand when separating and highlighting the details of the chaotic guitars in the centre of the image. But, even though the Andromeda is more detailed, I wouldn’t say it projects a larger or more 3D soundstage than FH15.

Conclusion: 5/5 - Excellent

Source Pairing​

FH15 is not picky. I have great results with the built-in DAC/amp of the Nintendo Switch. The soundstage does open up a bit when I switch to my K7 DAC/amp or my Shanling M6U music player, but I don’t feel the need to use these better sources.

Conclusion​

Despite my quibble about tonal balance and timbre, it is clear that FiiO successfully achieves a fun bassy sound signature with FH15. Suppose you have been yearning for a bass cannon with a slightly subdued midrange like E5000, but with better clarity and not as tricky to drive. In that case, the FiiO FH15 is a good candidate.

Pros:

• Large and deep soundstage with good layering
• Big and deep-hitting bass
• Fun tuning that works well with commercial music
• No harshness across high frequencies
• Good sense of macro-details and separation

Cons:

• Tonality tilts a bit too far in the warm and dark direction
• Timbre and tonality of acoustic instruments are not entirely correct
• Micro-detail retrieval is only average

Updated: March 4, 2023

Fiio FH15 ($229)​

Intro​

I recently purchased the Fiio FH15 from Amazon US for $229 for the purposes of a review as well as my unending curiosity for what is out there in the great Audioverse. I am a blind buyer and I do not advise anyone to do the same. It doesn’t always end positively. Anyways, about the FH15, it is another in a long line of ‘FH’ series of iems. Fiio uses the ‘H’ in the name to define that this particular set is part of their ‘Hybrid’ line of iems.

Well, we shall see how Fiio’s newest hybrid fares against the ever-growing sea of quality iems within the price point. In all truth, I wanted to find out if the FH15 could best even some within Fiio’s own lineup. I want to thank anyone who chooses to read my thoughts and I do hope this helps you in making a purchasing decision.

Fiio is now what you could call a “storied company” as they have been around long enough and are certainly more successful than most. As for me, I have owned many Fiio iems and audio devices. One thing you can count on with a Fiio set is the fact that they will always strive to go ‘over the top’ with their quality per the price. Most of the time their tuning is pretty spot on as well. They have had some ‘not so great’ sets but have also had quite a few fantastic sets as well. Fiio seems to always bring a premium vibe with great build quality and a striking appearance with the majority of their iems. In this case, the FH15 is no different. With that, let’s get into my full review of the Fiio FH15…



Later Comparisons: Fiio FH5 / Aful Performer 5
Review can also be found HERE

Gear Used​

–Shanling UA2
–Moondrop Dawn 4.4
–Ifi Go Blu
–iBasso DX240 with Amp8 MK2
–Shanling M6 Ultra

Packaging ​

Oh Fiio…you just know what we like. We like stuff and stuff is what you give. Let’s start with the packaging. The box is a larger rectangular shaped black box. Upon the box you’ll notice there is a sleeve. On the sleeve is a graphic of the FH15 themselves as well as an intricate blueprint type drawing of the Internals within the FH15.

Slide off the sleeve and you get the actual box which has a flip top. Open the top and there is some reading material. Under the reading material you finally see the gorgeous FH15’s in plastic cut-outs. Pick that level up and you are met with the carrying case, nozzle tuning filters and a very nice plastic case full of tips. Inside the carrying case is the cable along with the connectors, nozzle brush & mmcx tool. The presentation is very well laid out. In fact, not many companies do it better.

Carrying case​

The case provided is the exact same case you’ve seen a thousand times from Fiio. I expected nothing else. The case is similar to the popular Pelican style cases. This one in particular is made of very hard plastic and is extremely durable and watertight. These actually are very nice cases to throw in a backpack as your iems will never get crushed and will be perfectly protected anywhere you go. Not much more on the case other than it is always a nice addition. Of course, I have about ten of them now and truthfully, I don’t use any of them.

Tuning Nozzles ​

I always love to see tuning nozzles. I don’t really have a good reason for that except that I love to switch up the sound to suit my desired taste at any moment. As for the tuning nozzles provided with the FH15 you get a nice little stainless-steel slab with four holes which are all screw tapped so that you have a place to store the nozzles themselves. The tuning nozzles are either “Bass”, “Balanced” or “Treble”.

What gives? ​

I have to comment on this; I own the Fiio FH9 (My FH9 Review) and I complained about the tuning nozzles that came with that set because they are FREAKING TINY!! Fiio what is the deal?! They are so miniscule that simply screwing them into the slab is like prepping for surgery. I’ve grown up fixing things, I was a pipefitter, steel worker, welder and finally a Mechanical Integrity Inspector and I fancy myself very mechanically inclined. However, these filters are so small it’s hard to even get your fingers on them, let alone having to actually align the threads on the filters with the tapped threads of the base! Seriously Fiio?! Why would you add filters that are so miniscule? Okay I’m done…Moving on.

Change or no change?​

Anyways, the filters don’t make the greatest difference in the world. Yes, the bass filter seems to add some sub-bass judder, and the treble filter slightly opens up the lower treble region, and yes, the balanced filter is somewhere in between. That said, the difference is very slight between them all. I choose the treble filter only because the bass isn’t affected, and it does help to give a teeny bit more air up top. I don’t foresee myself changing back to the other two for any reason.

Eartips​

Fiio is awesome. Name another brand that just throws quality tips at you the way they do. In total you get 16 pairs of eartips. Three pairs of “Vocal” tips, two pairs of bi-flange tips, three pairs of “Balanced” tips, two pairs of “Bass” tips (basically KBear 07’s), two pairs of memory-foam tips and three pairs of Fiio’s “HS18” Vocal tips. Phew…That’s a mouthful. Anyways, I won’t go into detail about the tips, but I will say that Fiio only provides quality tips which absolutely help to dial in the tuning of your earphones.

I actually decided to use a different set of tips which seemed to work best for me. I went with a shallow fit wide bore eartip of unknown origin. You see them all over the chi-fi world and its likely you may have a set like the tips I have pictured. Anything to bring down the low end a bit and open these bad boys up will help, in my opinion of course.

Cable​

I love a good cable and love when I don’t have to purchase an extra cable. I love even more when that nice cable is a modular cable. First off, the cable that Fiio provides is a 152 strand Silver-plated Monocrystalline Copper 8 core cable with a Litz braiding.

Fiio provides both a 3.5 single ended jack as well as a 4.4 balanced jack which gets pushed into the modular housing on the cable and then screwed tightly in place. It is actually a great system for a cable such as this. However…

Fiio chose to negate the 2.5 balanced which I suppose is in line with the industry but if I’m paying over $200 for a set of iems with a modular cable… just add the 2.5. As if 2.5 balanced connections do not exist anymore… Fiio?? How much are you saving by not including said 2.5 modular adapter? Anywhoo, not a big deal, unless of course your beloved balanced source is 2.5! Instead, you have to purchase a 2.5 male to 4.4 female adapter when the 2.5 adapter could have easily been added for a couple measly bucks, Fiio… Do better. Honestly people, I don’t really care at all…Lol.

Moving on, the cable is very nice, but I do have some small complaints. First, the jacket which covers the cable is that stiffer plasticky material, it isn’t very soft at all. The problem is that there is some microphonics which occurs very easily every time the cable rubs against your shirt. Obviously when music is playing the sound is muted to a small degree but, it’s still there. Another thing I don’t completely enjoy is when rolling up the cable for storage it does tend to have a mind of its own. Like a spring there are times it just doesn’t want to stay all nicely rolled up and almost “PINGS” out of shape. That’s it. Those are my complaints. In truth it’s a very nice cable.

Build / Design / Internals / Fit ​

Build​

The Fiio FH15 is very well constructed and typical to a Fiio set of iems. Built entirely out of five-axis CNC machined aluminum, the FH15 is a bona-fide STUD in the build quality arena. Of course, this is a common theme with Fiio products. The FH15 however is the culmination of four years of tinkering in the build, design, as well as the internals. As far as the build is concerned the FH15 has a very solid, yet smooth and premium feel when in hand. Fiio added female threads to the nozzle to screw on the different tuning nozzle filters which I spoke on earlier. Also, Fiio did add red and blue rings around the mmcx connectors to help in determining which side is which. I’m sure that will help some newbies who may need it.

Fit / Isolation​

Fiio’s build team did a wonderful job of creating an almost perfectly ergonomic shape which sits perfectly in my ear. The Fiio team machined this set perfectly smooth and comfortable for long listening sessions. The shape is much like some older Fiio iems; the Fiio F9 and F9 Pro and the FH1. The FH15 really does sit perfectly in the ear which aids in getting an appropriate seal, at least for me. This also aids in isolation from the outside environment as the passive noise isolation is very good. Sound leakage is not an issue either as very little can be heard from others as you jam away to your music. I also really enjoy how light the FH15 are. Honestly, once this set is in your ear you will forget about them as they feel like nothing at all.

Design​

The FH15 is a fantastic looking iem in my opinion. Incorporating a Dragon Scale theme carved into the faceplates gives the FH15 a very bold, very masculine and very bad-ass look. The FH15 are all black except one golden colored ring accent which circles the dragon scale faceplates. Very dope!

Internals​

Fiio decided upon a four-driver hybrid system. That is, one 10mm Carbon based diaphragm dynamic driver to cover the low-end. Fiio states that the material used is 9 times harder than steel and ¼ lighter than beryllium. Producing the midrange is one custom Knowles ED balanced armature, while the treble is using two Knowles RAD balanced armatures.

Fiio patented designs​

Fiio also opted to use their patented S-Turbo design for the DD. This was a work-around that Fiio designed to get away from using a LC Low-pass filtering circuit which takes up quite a bit of space. This design reduces frequency response overlap helping to better divide the spectrum cleanly. Another design choice was a custom-built notch filter system which uses a Helmholtz resonator in conjunction with the mid frequency Knowles ED driver. Think of blowing air across the top of an empty glass bottle. The basic principle is capturing the air resonance in an empty space. The notch filter system adopted by Fiio is similar to this understanding. Said to improve the 1k through 4k area of the mix by giving denser mids, richer vocals and is meant to add more of a realistic timbre and weight.

Drivability ​

The FH15 is not a difficult set to drive at 16 ohms with a sensitivity of 112 db’s. Using 3.5 single ended on the Shanling UA2 the FH15 sounded very well composed and I truthfully saw no real issue sonically. In fact, the FH15 sounds great with lesser power. Now I don’t have a phone with a 3.5 jack so I can’t report how the FH15 sounds using such a device. I can tell you this, if you feed the FH15 from a better and more sonically gifted source, the FH15 will reward you. From the Ifi Go Blu, to the Moondrop Dawn 4.4, to my daps, the iBasso DX240 and the Shanling M6 Ultra, the FH15 sounded highly dynamic. I would say the FH15 does seem to scale to the quality of the source and not necessarily the output power.

Source​

I do think that better source pairing of the FH15 will make a noticeable difference. The FH15 is warmer and lusher and so finding a source which has a tilt to the neutral or analytical side does help the sound quite a bit. For myself, I found the best synergy with the more neutral Moondrop Dawn 4.4 as well as the iBasso DX240. My Shanling M6 Ultra isn’t overly warm but it does have a more robust low-end and it shows itself even more when paired to the FH15. I would simply be aware of that if this is a set that you are looking to purchase.

Quick Sound Impressions ​

The words which spring to the tip of my tongue when describing the Fiio FH15’s auditory ability are rich, full and BOOM. The sound of the FH15 is simply full. However, if I am to break it down a little further, I would call the FH15 a very hearty sounding, but rather light V-shape to almost an L-shaped sound signature. There is very good coherence between all the drivers as they melt into each-other very well. I hear a more natural sound across the spectrum minus the more colored low-end.

The bass is a BANGER! The FH15 hits hard and does so with good authority. The midrange has a very rich and weighted timbre that is more forward than it isn’t. The treble rolls-off quicker than usual with decent body and comes across nice and smooth yet also isn’t deficient in the details arena. If you want a full-bodied representation of your music then I may have the iem for you, with one caveat… You can’t be scared of lil bass. There are definitely some subjective issues that I have but all things considered Fiio did a pretty good job here.

Fiio says that they took some cues from the legendary Fiio FH5, as the FH15 is supposed to be a follow-up. I honestly don’t see it completely, or, shall I say, hear it. That said, in some ways the newer FH15 is a step forward or possibly a step back depending on what it is that you prefer. I will compare the two later on. That said, let’s take a look at each 3rd of the spectrum.

​

Bass​

Fiio added about a 10 dB rise in the bass section and it shows. On paper the FH15 definitely has a sub-bass emphasis but really the sub & mid-bass do well to share the spotlight down low. No doubt this set hits with deliberate potency. I hesitate to call this set a basshead iem because of the immediate stigma attached to the mantra but… the FH15 can bang! There is this unpliable and rigid density to the bass region that comes across nicely separate from the mids and highs. This is where Fiio’s patented “S-Turbo” tubing design seems to show its worth. Of course, the FH15 is not very well balanced with the rise in the low end which skews everything and tilts the replay to the warm side of things. Personally, I would’ve liked to see a few db’s less in this region but… I’m not everyone else.

Either love it or hate it… ​

For those of you who enjoy a bigger bass, then I would say you’d be hard pressed to find many better at or around this price point. For the large quantity, the FH15 is well in control as the bass is pretty agile and clean. However, if you value a more balanced approach with tighter and snappier bass then I would assume the FH15 isn’t for you. I suppose I can begin to really enjoy the FH15 when I listen to it… for what it is.

Now, if I were to draw out my perfect tuning, I would like a hair less bass rise down low but since it’s there… It isn’t hard to enjoy. Nobody ever said that this audio game has to be one thing or one “audiophile” template which all others should aspire to. I simply want you (the reader) to be aware of what you are getting here.

Sub-bass​

The FH15 has substantial haptic vibration with good depth and weight. “Elevators (Me & You)” by none other than Outkast begins with that legendary bass line… the FH15 does its perfect justice. Each bass drop hits hard but comes and goes relatively quick. It’s clean for its purpose. Its tight for its size. The sub-bass is dense with a well-adjusted transient response to my ear… PER THE TUNING. I find the sub-bass rumble to be very rewarding for Hip-Hop, EDM, Metal, R&B and even Pop, but it doesn’t fit all genres perfectly.

The sub-bass is perceivably dexterous and nimble yet hard layered. Like in the jam “Never Left Memphis” by Austin Jenckes. I can feel the bassline judder and jive through the melody with good cadence for its size. Or “I Love” by Joyner Lucas. The sound is so deep in pitch, which adds this other dimension to the bass. Very hard and solidified with a guttural thrumming when called upon and with very nice extension for fans of deep bass.

Mid-bass​

The mid-bass follows the lead of the sub-bass and really has a nicely rounded slam that keeps it very well in control. In “Billie Jean” by Weezer the kick drum is pretty tight, and it booms with depth and fantastic tactile surface texture. Nothing even remotely fuzzy or pillowy on the surface while the fundamental frequency of the kick drum is flat out bulbous and water-logged with density. This song on the FH15 has a hard-edged cleanliness that not all iems can duplicate. This is why I always use this track for my reviews. The FH15 really does well with this one.

Another good example is the bass guitar riff which begins the song “John Wayne” by Whiskey Myers. The FH15 is flat out angry on this track as it growls with purpose. There is this robust & gravelly-grunt to the sound that grabs my attention. There’s a very gradual decline from the sub-bass to the mid-bass which leaves plenty of presence for instruments like bass guitars, kick drums, lower snares as well as deep baritones etc. etc. I possibly would have liked to see the mid bass begin its roll-off a hair sooner with slightly less rise in the sub-bass, but Fiio did a decent job at presenting a bigger than average bass which sounds very kempt, tight and clean for its size.

Acquired taste ​

There are some downsides as well though, I am 100% positive that many will think this is too much in quantity. In fact, it is a hair too much for me at times. The bass can be over-reaching and almost coat the rest of the mix in a very slightly weighted blanket of warmth. The warmth added from the bass section cascades throughout the whole of the spectrum and without a doubt carries the greatest emphasis. I would almost call the sound L-shaped, but I do think it stops just short of that. Not everyone enjoys a warmer and heavier sound, in fact, the FH15 has been an acquired taste for me. I can stretch my love of audio to many different sound signatures, but I don’t think that everyone will share my enthusiasm.




The whole of the midrange on the FH15 is pretty forward with an almost wet and lush presentation. There is great body to all voices as well as instruments whose fundamental frequencies live in this area of the mix. This is not the most detailed mid replays I’ve ever heard, but it is very clean with okay resolution. You won’t hear anything dry or analytical or thin and you won’t hear any annoying sibilance either. There isn’t anything shouty or anything which would be considered glaring and peaky as I hear a more gradual pinna rise. You will hear a non-fatiguing midrange that still has good energy and presence. Yes, there is a warmer hue to the delivery but there is a certain charm to the sound that I enjoy.

Lower-midrange ​

Male vocals are very well sculpted. From baritone to tenor the weight of each voice is evident with great texture to those voices. The note definition is decent with clean lines and a robust sound. “Travelin’ Soldier” by the acapella group Home Free presents every different pitch of the male voice (5-member band) and I just think the FH15 nails them all. It’s just like I wrote earlier, from deep baritone to tenor, there is a certain life-like weight to go along with a smoother and richer sound. The intonation of the different male voices rising and falling to the melody shows off on the FH15, as each voice is rendered distinct and separated from each other. The baritone has that clean and deep droning crispness to his voice while the higher pitched males sound more slender and airier with a nice, contoured note outline.

Upper-Midrange ​

The upper midrange is where most female vocals are heard and with the FH15 there is a very musical and full nature to female voices. “Mariana Trench” by Gabrielle Aplin sounds fantastic. Listening with the FH15 I hear that well-articulated melody within her sweet voice. There is a light shimmer in her harmonics that never goes overboard, always stays in control and is very resolute. The FH15 catches the softness and the smooth character and gives off a fully emotional sound with depth and musicality. I realize it seems I am just throwing out different “audio” words, but the truth is, I’m simply describing what I am hearing the best I know how. Lush, smooth, clean, musical… I suppose I could’ve ended this paragraph with only those words and saved some digital ink in the process. That said, females sound great on the FH15.

As a whole… ​

The midrange is not one which caters to the finest of details and in my opinion that is its strong suit. There isn’t that dryness and thinness which detail oriented iems seem to invoke. Instead, I hear a melodic & rhythmic midrange with a penchant for the dramatic from a pretty quick driver that handles this area with lush finesse. I am actually surprised at how well the ED Knowles BA takes care of the mids. You have that thicker timbre with a nice marriage of smooth and crisp that makes the FH15 pretty agile and easy to listen to.

I should add that Fiio didn’t completely negate the finer details within a song. They are there and some tracks display them better than others. More complicated songs with more moving parts and commotion will obviously stress these drivers a bit but that goes for any set short of some well-done Planar iems. Or songs which have more pronounced low-end activity, the FH15’s bass region might blanket some of the minutiae. The FH15’s midrange is actually quite good at illuminating some micro details, especially for how this set was tuned, which certainly wasn’t to be a technical marvel. Mostly macro but at times… there’s some micro too.




The treble area is very easy going. Fiio did not overly emphasize this part of the frequency and I’m sure for many this will be a point of contention. Definitely this will not appeal even remotely to any treble Heads. However, the treble does follow suit with the rest of the mix in that it is very smooth and full sounding. What I don’t hear is that nicely energetic treble which could offset the low-end a bit more to add some levity and more air to the sound. Part of my issue with the treble region revolves around the puzzling idea to begin the treble roll off around 6k-7k. However, the dissent is a very gradual slope which still adds info further out. Just not as energetic as I would like, and I am sure that many people will feel the same.

I say all of that, but I will also say that the FH15’s treble area isn’t devoid of details either, and there is still decent enough energy up top to not “totally derail” the FH15. Yes, it is more relaxed and attenuated from other sets within the Audioverse but it is also clean and pretty nimble. Fiio decided on using two RAD Knowles BAs to handle the treble and what they succeeded in was not giving off an incoherent, tinny, or metallic sound in this area.

Held Back​

“Don’t Say it’s Over” by Gaz Coombes has some treble activity which I feel could use a bit more vibrancy as those areas is supposed to support and enhance this track. What you get is a more subdued version of the song, or a more relaxed version. Understand I don’t think it is bad by any measure as what you do hear still has good body and isn’t grainy or flat and the timbre isn’t out of whack. It’s simply held back some and I feel that you lose out on some of the most important info. This is kind of a running theme, but it isn’t always the case on every track. I suppose much will be determined by what genre you mainly listen to.

Could use some air​

The secondary harmonics of cymbal strikes is again, a bit held back, but in the same breath those cymbals aren’t tizzy or unnatural which tilts the scales in the favor of the FH15 in my eyes. However, in tracks with a bit more commotion, those same cymbals will be quite attenuated. Obviously, this relaxed sound is more noticeable in tracks which have more activity in them from the low end but there is a number of songs in my test tracks where I don’t notice this as much. However, as a whole, the treble could most certainly use some air. This is something that I can at times overlook when I’m wrapped up in a casual listening session but I’m positive that others will not be able to overlook this.

What’s nice about this treble is that you won’t come across any sibilance or anything peaky. There aren’t any awful spikes, and nothing comes across as peculiar, or irregular, or completely unnatural. I don’t think that the treble is so relaxed that I would call the FH15 “Dark”, but it is warmer and that most definitely is in relation to the lack of rise in this area.

​

Technicalities ​

Soundstage​

The soundstage is represented with very nice depth to the field of sound which adds to its ability to layer those sounds. The width isn’t the widest that Fiio has ever produced but I also don’t think it’s abnormally small or closed in, just not super wide. Height is about average and also isn’t overly enhanced. I say all that to say that the stage size comes together very well with an appropriate replay of my music.

Separation / Imaging ​

Separation of elements within the imaginary stage is actually quite good. Not perfect, but good. The separating of instruments and voices goes hand-in-hand with the FH15’s ability to image well. In fact, imaging is also pretty good, as it should be. Perceived driver speed, depth of stage, clarity, decent resolution and multiple drivers working in tandem help to achieve a nice psycho-acoustic image of a stage. However, I could argue that there is the slightest veil which impedes the FH15 from being even better.

Details​

I’ve partially covered this section throughout this review, but I will reiterate what I’ve said. The FH15 isn’t tuned to pick up every breath in a mic or hiccupping audience person 10 rows back in your favorite live jam. It simply isn’t tuned to take on the detail monsters within the audio world. Yet still, it isn’t bad at all. I can say without batting an eye that you can find much better in this area for far less money. However, that’s not why you would purchase this set though. You purchase the FH15 for the fun factor and whatever other descriptive words which describe auditory joy. You wouldn’t pick up this set because of its hi-res ability to capture micro-details. It’s about the fun factor, or the guilty pleasure for some of you audiophile folks.

Comparisons​

*Note: For the comparison portion of the review, I want you to know that these are never a duel to the death. I try to use other iems as a tool for explaining (to a degree) the set that I am reviewing. I hope by explaining some of the differences that it will help in this task. Also, I present some very general differences and will not go into great detail explaining myself. Most comparisons take me around an hour or more of constant back and forth A/B’ing between sets using the same source always.

Fiio FH5 ($150-$250)​

The Fiio FH5 was the first iem that I ever purchased for over $250. I absolutely adored the sound of this set and guess what, I still do. Yes, there are issues but what fun is an iem without issues? Don’t answer that, it was a very stupid question. Anyways, the FH5 comes equipped with a total of four drivers (why wouldn’t they name it FH4?). It has three Knowles Balanced Armature Drivers as well as one 10mm Polymer Nano-Composite Ferromagnetic Dynamic Driver. That was a mouthful. The FH5 is built like a tank, it’s beautiful and it still holds up. So how does it handle its much younger sibling?

Low-end​

Starting off with the bass region, the FH15 and the FH5 are very close in terms of quantity down low. I do feel the newer FH15 is perceivably tighter and sounds a hair more robust. The FH15 has much better texture with cleaner note definition. Granted, the FH5 sounds fantastic but this newer DD that Fiio is using (in the FH15) is flat out more precise with a speedier approach while slamming harder. No fuzz on the FH15 to slight fuzz on the FH5. That’s what almost five years of driver innovation and implementation gets you.

Mids​

Male vocals on the FH15 and the FH5 are very close in tonality but I do notice that there is a slight bit more of a full sound on the newer model. The leading edge on male vocals is a hint crisper on the FH15 but both come across clean and well bodied. The FH15 does sound a hair warmer as well. Female vocals on the FH5 are slightly thinner but a pinch more shimmery too. They sound just a little bit more resolute than on the FH15. However, the FH15 has a more emotional pull to the sound with a lusher presence. I like them both as they take a different approach to a slight degree. Both sets do very well in vocals, and I honestly feel this is a draw.

Treble​

The treble on the FH5 is more pronounced and slightly dryer to the relaxed and bodied playback of the FH15. Details are illuminated a bit better in the older model mostly due to having more energy in this area. Truthfully the note definition within the treble of the FH15 is just as good yet with a more subdued approach. That being said, the FH5 does add that last little bit of luster up top which changes the overall tonality of the mix to make it just a hair less warm and more vibrant.

All things considered… ​

Both sets are very well coherent, and both represent my library just fine. I feel the FH15 stands out a little bit by offering cleaner note outlines across the mix. It also has a more emotional sound with tighter and beefier bass drops and more grunt with bass guitars. It’s close though, as these two are not miles apart. I do like the overall tonal temperature of the FH5 and do wish that Fiio would’ve either dropped a few dB’s in the bass or elevated the upper-mids and treble a bit more on the newer FH15. So, these two are not tuned exactly the same and they don’t sound completely alike. I do not understand how Fiio can say that the FH15 was designed after the older model when there are apparent differences. Oh well, I like them both.

Aful Performer 5 ($219)​

What a set! The Aful Performer 5 or “P5” as I’ll call it Is a wonderfully tuned iem within the same price point as the FH15. The P5 is an almost neutral sounding U-shaped set with nice balance across the spectrum and honestly… the P5 is an over-achieving golden child in my book. Sorry FH15. However, it makes complete sense for me to add the P5 for comparison’s sake. Both sets are relevant and newer, both are around the same price point, and both are DD/BA hybrids. The P5 has 1 Dynamic Driver as well as four custom Balanced Armature Drivers. I still have yet to review the P5 but that will be coming soon. Please check out Mahir’s review of the Aful Performer 5 HERE.

Low-end ​

The FH15 comes with much more slam and definition in the bass region. The P5 in comparison is the slightest bit more pillowy while not “pillowy” persa. The FH15 has a cleaner sound on bass drops but also has a hint more in overall bass mass. I say that but the P5’s bass makes more sense to the whole of the mix whereas the FH15 almost adds too much warmth and gusto down low.

Midrange (Male vocals) ​

The P5 is simply more natural and organic replaying male vocals, which is saying something because I feel the FH15 does a commendable job at presenting male vocals. The FH15 has thicker note weight and is much lusher and fuller. Still the difference shows itself most in tonality and timbre of the P5. The P5 has better levity in the replay, and livelier energy with a more detailed midrange. Both sound great and both make an argument here but as far as my time goes during this comparison… The P5 sounds better to me most of the time. I did say most. There are some deeper male vocals that sound a pinch better to my ear on the FH15 but those are rare. However, as a whole I’d say that the P5 has the more balanced, detailed and natural sound here.

Female vocals​

Females are exactly the same story. The FH15 is richer, bolder and even has more of an emotional tilt. Still, there is shimmer on the P5 that the FH15 cannot replicate due to the treble roll-off. Now on some tracks the FH15 actually does fare better and that especially shows up on more acoustic style emotional songs. However, those are also few and far in between. The P5 has that natural and earthy controlled sheen that still has body as well as an easier time catering to the accentuation and cadence within a woman’s voice. It isn’t miles apart though, because the FH15 does vocals very well.

Treble​

This will be short. The P5 is simply better. The choice of Fiio to forget about the treble is a dagger to the heart when compared to a set like the P5. The P5 has a wonderfully smooth, organic, energetic and technically astute treble region. The FH15 has body, decent extension and pretty nice details and is 100% non-fatiguing but the P5 just does it better. Obviously not all genres and tracks use a ton of treble activity but for the most part just having the boost in the P5 up top helps other regions perk up a bit. Now, if you are one who loves and adores a warm, subdued, yet clean replay with a completely non-offensive sound then look no further than the FH15. Everyone else… the Performer 5.

All in all… ​

I knew what this comparison would look like the second I decided to compare the two. Maybe it wasn’t fair. Maybe I should’ve gone with the TRI I3 Pro instead, which is a warmer sound as well and would have been a relevant set to compare the FH15 to. Anyways, I suppose I could also simply Chalk this comparison up as a preference battle. They are far enough apart from each other tonality wise that it would all really come down to your preference anyways. Do you like Bassy, warm, lush, smooth and pretty clean. Or do you like neutrality, naturalness, resoluteness and details with effortless musicality? At any rate, I do hope it helps in comparing the two.

​

Is the FH15 worth the asking price? ​

Absolutely the FH15 is worth the price…if…the description I’ve tried to lay out sounds like it fits your preferences. If you are a neutral lover or treble head then the FH15 should probably cost about $15, and that would only be because of build quality and accessories. However, if deep and penetrating bass that is just as clean and taught as it is big and robust sounds like a dream, well, I would say the FH15 is well worth the money. If a smooth, easy listening and non-offensive treble with some of the most rich and milky midrange vocals in its price point sounds appealing, I would say the FH15 is well worth the money. So, to answer my own question… Maybe.

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Conclusion​

I have to be honest, the FH15 juuust misses the mark for me. It isn’t that I don’t enjoy this set either, as I actually do enjoy it quite a bit. Ya know, for these reviews I really have to bend the scope of what it is that brings me enjoyment. I do so because no matter the product out there, somebody loves it. I really try to retrain my mind to find enjoyment in any sound signature. For all intents and purposes, I normally am able to do just that. It doesn’t hurt that my library of music is quite literally all over the place.

Truth be told, I had to do just that with the Fiio FH15. However, the FH15 is simply lacking that last bit of treble air for me. Can I enjoy the sound? You bet! A large chunk of my music sounds fantastic on the FH15. Also, I am sure that there are many of you who will absolutely adore the sound here. Keep in mind, when I say “miss the mark” it doesn’t mean that I think that the FH15 isn’t a good set. It is good. Maybe it isn’t perfect for me, but it will be to somebody.

To conclude this review, I want to first ask anyone reading to now go find another review of this set, and then another. I can promise that I give my absolute honest opinion and do the leg work every time I write a review, however, we are all different. We may have different gear, different likes and dislikes, different hearing abilities and we all haven’t been on the same audio journey. So please do yourself a favor and check out some other views. I can’t thank you all enough for spending your time reading anything that I take the time to write. The process is a long one but very rewarding and I do hope it helps even one person. So, thank you everyone, please take good care and stay safe.

The review sample was kindly provided free of charge in exchange for an honest review.
I didn't receive monetary or any other kind of compensation and I don't use affiliate links.
The price of the FiiO FH15 is $229 and you can order it from here.



FiiO FH15

The FH15 is FiiO’s new hybrid in-ear monitor that introduces the company's brand new naming scheme that is a little bit confusing to memorize.
This is literally the successor of the FiiO FH5 and FH5S.
You can read about the new naming scheme in the following illustration.



Anyway, back to the FH15, the configuration consists of 3 BA drivers together with a single dynamic driver.
Equipped with a brand-new 10mm dynamic driver with carbon-based diaphragm, the FiiO FH15 features excellent transient performance. In this device, the carbon's lightweight, strong rigidity and high internal resistance means that the dynamic driver can quickly start and stop movements when responding to changes in the input signal.
For mid frequencies, the FiiO FH15 employs a custom Knowles ED BA driver which works in conjunction with specially placed tuning holes in the shell.
Treble is handled by 2 Knowles RAD BA drivers, which are capable of high treble resolution and capture every last detail in the music, for a truly airy sound.
The FH15 also features a custom-made notch filter.



A Helmholz resonator is designed to work with the mid-frequency drivers. When the soundwave is at a particular frequency that the Helmholz resonator is designed to work with, the volume of sounds with this frequency is enhanced as the resonator concentrates and resonates that frequency. Additionally, the resonator is connected to a thin opening to eliminate any unwanted resonance peaks and overlapping frequencies produced by the different drivers, in order to achieve better coherence among the drivers while also eliminating sibilance.
The FH15 also employs FiiO's S.Turbo patented design and comes with three interchangeable sound filters for a slightly different sound signature.
Red filter is for enhanced bass, black for balanced sound and green for exquisite and highly resolving treble.



Design, fit and build quality

The FH15 utilizes an aluminum alloy construction, which when combined with the dragon scale design elements allows the shells to have a unique and exquisite look.
This new type of housing is an evolution of the one found in the F9 Pro (do you remember them?) and has a relatively low, rounded profile that follows the contours of the ear offering a very comfortable, stable and stress free fit that is aided by the lightweight construction.
The new design is much better looking and comfortable than the previous generation housings of the series while the closed back design offers very good passive noise attenuation.
Build quality is simply excellent, the finish is flawless and smooth while the earshells look super durable.



Cable

The FH15 comes with a 152-wire silver plated monocrystalline copper cable featuring 8 strands of Litz-braided wire and MMCX plugs.
The Litz braiding specifically reduces the skin and proximity effects, leading to reduced eddy current losses and thus improved high-frequency resolution.
Additionally, the audio plugs are swappable, and included are 3.5mm and 4.4mm plugs but not a 2.5mm that is still commonly used.
The cable is of high quality with aluminum plugs and splitter, it has very low microphonic noise and it doesn't get tangled.



Accessories

As always with FiiO you get a great assortment of accessories.
Except for the cable and the sound tuning filters you also get a standard plastic carrying case, a MMCX removal tool and a cleaning brush.
The ear-tips include the brand new HS18, balanced, bass and vocal in three pairs each, two pairs of dual flange and two pairs of memory foam ear-tips.
An all inclusive and pretty amazing package for the price.



Driving Efficiency and associated gear

The FH15 has a 16Ω of rated impedance with 112dB/mW of sensitivity so they are very easy to drive and you can use them straight out from your phone's headphone jack.
Of course you can do much better with an entry level DAC dongle like the FiiO KA1 or for the best results you can use something like the FiiO KA3 or M11S because the FH15 scales pretty well and will reward you with great sound.



Listening impressions

The FH15 is a smooth, balanced and full sounding IEM with a touch of cozy warmth and a rather forgiving treble.
It is very musical sounding with natural timbre and great sense of realism.
There is great sub-bass extension followed by a tastefully emphasized bass that extends into the mid-bass but not too much as to severely affect mid-range clarity and presence.
You can tame the bass a little bit by using the treble filter and the HS18 ear-tips but the latter will also affect the weight of the texture with the result of a drier and leaner sounding bass which otherwise is full bodied and visceral.
The bass is dynamic, contrasted and impactful with plenty of punchiness but it can sound a touch hollow and a little slower than ideal.
Nonetheless, it is mostly controlled and tight with plenty of shading and excellent definition for the category.
Simpler classical works will sound good but with more demanding symphonic works where the bass line gets busy and complex, the FH15 will sound a touch one-noted without too much layering and definition.
The tonality is not that off-pitch, you can equally enjoy bass heavy and acoustic tracks without too much coloring.

The transition from the upper-bass to the mids is smooth without veil but there is a certain lack of transparency and clarity that disappears as we climb higher the range.
The integration between the two drivers is coherent and the mid-range doesn't sound detached relative to the bass.
The tuning is balanced and natural with a convincing tonality and a lifelike quality to the voices and the instruments.
The overall clarity is satisfying, the mids sound articulated, full bodied and present with good refinement and plenty of harmonic wealth albeit not that well defined and airy for critical listening.
The FH15 has an easy tuning without frequency exaggerations, it is easy to the ear and warm without sibilant or shouting vocals.



The same qualities apply to the treble which is quite safely tuned for a smooth and forgiving listening experience but without sacrificing in extension and resolution.
The FH15 is in no way veiled or dark sounding, there is plenty of energy and crispiness to keep things moving, detail retrieval is very good for the category but there is a certain lack of endgame resolution and transparency.
This is not necessarily bad because not all people like bright, analytical and treble forward sounding earphones so if you belong to this category you will be well served.
The treble filters make for a crispier and more energetic treble performance but they also add a couple of peaks that induce some kind of harshness and I ended preferring the balanced filters but your mileage may vary and you are welcomed to experiment.
Something of special mention is the excellent implementation of the drivers that don't sound detached or out of phase with the result of a very cohesive frequency response.
The FH15 unlike its predecessor, the FH5S, is of a closed back design so the soundstage can't reach the openness and wideness of the latter.
Still this is an open sounding earphone with a moderately expanded soundstage which is not by any means narrow or claustrophobic while it has a very satisfying positioning and separation.
The FH15 served me pretty well for non-critical everyday listening of classical music, especially with less demanding material like Mozart's early string quartets.



You can fine tune the FH15 with the HS18 ear-tips that when used will make the bass response a little more neutral sounding and not as emphasized in the mid-bass.
They also add some air and energy in the higher frequencies but they will also make the FH15 to sound considerably leaner, thinner and drier with less body and impact.

Compared to the FiiO FH5S ($250)

The bulkier and open back FiiO FH5S wasn't received very well because people weren't patient enough to allow plenty of time for the dual dynamic drivers to break in.
Sadly, because after that it is an excellent sounding earphone with a high quality, neutral, extended and technically strong bass, an engaging and transparent mid-range and a touch of forward and very energetic treble response with fine resolution and plenty of clarity.
Not to mention the super wide and spacious soundstage with the laser sharp imaging and the ability to fine tune the sound signature with the aid of the electronic crossover.
As you can probably understand these are two earphones that step into different sound directions with opposing sound signatures and it is not that difficult to pick your favorite one.



In the end

Musical, engaging and organic sounding with a nice touch of warmth, great tonal balance and good technicalities for the category, the FH15 is addressed to all of you who are treble sensitive and want an easy listening and non fatiguing earphone suitable for everyday listening with all types of music.

Test playlist

Copyright - Petros Laskis 2023.

Fiio FH15

The new Fiio FH15 is a renewal, revival and an update to an older aluminum alloy CNC machined shell shape similar to that of the old F9 and F9 pro but with all the advancements from the FH series of hybrids. Adding to the newer developed FH15 are newer customized Knowles BAs, dual BA for trebles, single BA for mids and a newly developed carbon based 10mm dynamic for bass. Fiio also incorporated a hodge podge of their design techniques to get the sound to what they had in mind. A notch filter incorporating a helmholtz resonator to work with the new ED Knowles BA to improve the mid frequencies from 1K-4Khz. In utilizing a dual BA for the trebles. More control and better articulation for the important treble region. S.Turbo bass tech allows for a full beefy bass end to work in conjunction with the rest of the frequencies.

So you can say the FH15 design is a culmination of a lot of what Fiio has learned from their prior offerings and this is a statement about their commitment to bring the best of what they know to a newer design. The FH15 also gives a bit of a tuning choice as it includes 3 nozzle filters for varying degrees of upper mids to treble dampening for a more personalized sound balancing. Add in a plethora of tips with a very nice monocrystalline copper cable with 2 types of modular connectors single and 4.4mm balanced and you get a very compelling offering from Fiio.

With that I would like to thank Fiio for providing a sample of the FH15 for review purposes. My views of the FH15 are based on a lot of hearing time and how they compare to the competition that I have personally heard or own at the price range. The score rating is also based on how well the IEM I am reviewing does at the price range. Obviously a budget set will not sound as good as a mid fi or upper-level set of IEMs. You can read more about the FH15 on their aliexpress sales pages here. The FH15 was burned in for a period of a weeks' time. Tested on my sources. Fiio K9Pro ESS, IBasso DX300Max, Fiio M15, BTR7, Shanling M6pro, IFI Gryphon, IFI Signature.

Progressive tuning and design.
That word progressive means there are ongoing design techniques to how Fiio brings out a new IEM and in this case the utilization of past techniques to bring forward something new. All their IEM cables have modularity. They include an astonishing 16 pairs of usable tips and always come with a nice quality carry plastic hard case. The IEMs themselves get the best of what was achieved and then implemented into the new FH15. Then they take it one step further and give the consumers some better drivers for the sound and then tunes the IEM with what was popular in the past but then adds a newer take on it. In a nutshell the FH15 is a forward thinking hybrid IEM. They remind me of a mix between the older F9 shell design, FH5 sound tuning and the FH3 bass for their sound make up. From how I understand it. Fiio takes their most popular IEMs sold in the past and then reinvents them, I think most IEM makers will do this but Fiio usually gives the consumer a clear reason to upgrade.

Build
Fiio uses more CNC machined aluminum alloy builds for their IEMs than using plastic or resin for IEMs. The rock hard aluminum chassis is a compact strong yet light, is a familiar tear shaped design with a new dragon scale motif for the outer shells. The shape is recognizable for its ergonomics and is regularly used for IEM designs but the build is about as good as you would expect from Fiio. I think Fiio did a great job in the way they look and how comfortable they are in the ear. It's not a physically big design but has some girth to the shells that houses all the drivers. Fiio likes to stick with mmcx builds and that is ok. The majority of IEM manufacturers are looking more and more into 2 pin builds vs mmcx nowadays but the good old mmcx if made right works just as good. The only issue with mmcx is that the shells have a tendency to spin or move around the connections. Otherwise I have no complaints about the build or the design of the FH15 and you're certainly going to get a wealth of quality accessories included.

Sound.
In reading the descriptor of the FH15 the tuners for Fiio mentions taking what was popular from their former FH5 and incorporating that into a new FH15 tuning design. I have to agree just from memory there is some FH5 DNA involved with how the FH15 was tuned, specifically how vocals shine for the FH15. The tuning is modified harmon based tuning with an elevation for its bass and mid trebles. You can say it is Fiios take on the harmon tuning but tuned more consumer friendly.

Fiio states they used all sorts of techniques, notch filter, tuning holes for the ED mids Knowles BA. Newly developed carbon based dynamic for bass using turbo s tubing ect. The end results? One of the better bass infused cohesive sounds from a hybrid and this one is more musical and forward and full bodied in presentation than your traditional v shaped IEM that has some type of recession. Its stage is also done well. Not exactly as wide as their current flagship IEMs the FH9 but the stage is somewhere between a reference wide to a moderate medium. More importantly there is absolutely zero confinement to any of the sound coming from the FH15. Spacious full bodied, richer in tonality than most Knowles based IEMs and most importantly versatile in how it sounds. However there are some issues with its bass presentation which I will get into in the sound descriptors.

Treble
The RAD treble Knowles BAs two of them in conjunction are used for the FH15. The idea of using two BAs vs one. Arguable if that gets you extra performance but it does give better control for the trebles with a side effect of getting better precision. This is the reason why the world's leading IEM manufacturers use more than one BAs for treble tunings. The RAD Knowles is a specific tweeter BA that gives very good details with a realistic presence to trebles and here we get two of them working together. Unlike the treble tunings of Fiios past, here we get zero treble spikes in the treble region and overall sounds more smoother for the treble vs something that seems artificially enhanced. At the same time trebles sound clean and have a very good handle for macro details and its precision is very apparent. Trebles has just a slight elevation for its mid trebles but again no grating 8Khz spike from the get go. This is the reason why Fiio includes their treble nozzle filter out of the box.

Nozzle filters affect trebles and upper mids of a tuning more than mids or bass end of the tuning. Hence we get a slight reduction of the trebles using the red balanced filter which focuses the tuning a bit more for its mids and vocals. The black tuning filter reduces the treble and upper mids even more so than the red filter giving the FH15 a warmer bass tilted L shaped sound. Some might prefer this but in all honesty there was a reason why Fiio left their green treble filter on the FH15 from the get go. This configuration sounds the best balanced to my ears vs the other two. So most of my review was based on the included open green filter.

Treble overall has a refined tonal quality to it with nothing really sounding forced. A more natural take on the treble presentation is always appreciated and hence the FH15 overall sounds like a much more refined FH5 as a result. Its transient qualities are nicely done with that clean precision that is neither too apparent or under-represented. Fiio finds a nice middle ground for ability and presence with this design and hence it sounds more refined. Treble tunings can make or break an IEM and here we get just the right touch of a nicely resolving treble tuning for the FH15.

Mids
Is where the old FH5 made a mark in the industry. Fiio loves to tune with mid presence and it is difficult to hear a Fiio made IEM with clear recession for its mids. Mids are more than just present for the FH15 it is definitely featured. The slightly forward mids presence seems to be the hallmark of what made the FH5 so popular and we get that with the FH15. A single ED Knowles was used to its mids presence and I have to say this particular BA made for Fiio shows some signs of its competition. I am talking about Sonion BAs. Knowles BAs traditionally are not necessarily known for their richness in tonal character but this particular Knowles BAs shows some of that in its sound character. I can believe this particular BA was chosen for its vocal properties and it clearly shows.

Vocal lovers rejoice; these are what you should look into. Fullness and present vocals be it male or female sound stupendous for the FH15. There is a sound correlation from Fiios sources and how the FH15 here sounds. I recently did a review of the K7 dac/amp and I can almost describe how that source sounds to the FH15 sound presentation. Having a substantial body of note for vocals and instruments is something I am appreciating more and more as I age. Nothing to me is more of a turn off for sound no matter how detailed it is than having a thin note weight on a sound. Thankfully the FH15 has none of that going on. If anything this is my idea of what musicality for IEMs should sound like. The FH15 has more than just a detailed signature, it has a substantial note weight involved as well. Its full bodied sound is something you're going to appreciate.

Instruments sound more accurate with greater note weight. It is not just the impact of the strings or the initial burst of auditory information. It's about having the right body, tonality a bit of an added richness with a clean separation of notes. BA timbre and all. These sound very natural for the mid bands and clearly stand as a strong aspect for the FH15. If musicality is an aspect you are looking for in a hybrid IEM. That is clearly how the FH15 was tuned. It isn’t an analytical set or are their detail aspects world class. It is at its sold price at the very upper edge of budget offerings, almost borderline mid fi category. In that sense I feel these offer the type of enjoyable sound tuning that a lot of folks will gravitate to.

Bass
The FH15 gets a newly developed carbon based 10mm dynamic handling the bass, a stronger yet lighter material used for its tactile and agile bass ability. Fiio is then channeling its bass energy using what Fiio calls S turbo tech, a type of focused tubing from the area of the driver that throws out the most bass to reduce crossover in the lower mids area giving the bass a cleaner separation from the mids and trebles. This works to a certain extent as bass has an enhanced focus for Fiios Hybrids including the FH15 but at the same time, the bass was tuned with more than a bit of moderation. The end result is a woofer like bass presentation that will accentuate the bass notes to a greater degree. If you have owned Fiios entry level FH3. The bass elevation on the FH15 seems to be similar from memory.

However, It is due to that strong bass presence on the FH15 that tips will play a very crucial role in how you are perceiving the sound of the FH15. Fiio provides a good variety of tips for the FH15 but I would actually try all the included tips and also look into your tip jar to find the one set that will provide the sound to your liking to balance out the sound. Tips do make a crucial difference from my testing so don’t be afraid to tip roll. It's probably something you will do anyway but I strongly encourage finding the one set of tips that will work. It will be the difference in a bass first sound to a more balanced sound.

Another aspect of the older FH5 hybrid was that it had a strong bass foundation and we get that with the FH15. I think Fiio got the most amount of impact and sub bass rumble out of the dynamic driver here but comes with a bit much in emphasis. It can sound like that if you're not using the right tips. Bass emphasis is not greater than what Fiio has tuned for their prior hybrids theFH3, FH5, FH5s,FH7s and FH9 but it seems the authority of the bass note seems a touch more forward in the overall balancing vs being more balanced. Bass can sound a touch bloated at times with not the best tightness. Don't know if that is the result of the S.Turbo tubing they incorporated. This tubing seems to create a horn effect for bass. Which, if you're a basshead than this will appeal to you but for folks that demand a certain level of finesse, refinement and articulation for the bass. These can come off a bit too much in the balancing.

If you're a bass fan that likes them some burly bass these will most definitely appeal to you. But for folks that want quality over quantity these might not cut it for you for its bass presentation. Its big bass presentation can hit any bass note with ease and digs deep in the process. Rumbly bass is a given but its texture seems a bit hollow. Depending on the type of music your listening to seems to be a touch forward at times and brings a bit more boom and bloom to the bass notes than what the sound engineer had in mind. Your sources play a key role here as well. I noticed sources that clearly have bass enhanced presentations seem to really bring out the bass more than what I consider a well balanced sound. A more neutral source seems to jive better with the FH15. I think for folks that love bass genres, how the FH15 presents bass will be welcomed, but for folks that are looking for a more accurate bass note and want a cleaner mids and trebles. The FH15 is not the best due to just how much bass is included for its make up. Having a healthy 10 dbs of bass is substantial for any IEM and controlling that bass will be a task for any closed-in hybrid IEM design. What I would have liked to see is a slight reduction of its emphasis by 2dbs.

I recently did a review for Fiios FH7S and those have an equal amount of bass but somehow the bass presentation on those seems better balanced with the overall tuning, possibly due to having more room in the housing with a semi open vented design? Possibly due to a better tuning? Or a combination of both. To be fair the FH7S is almost double the price of the FH15 so in that regard one would expect a more refined sound. Its just that the FH15 mids and trebles seem to be of a higher quality vs its bass end. But again this is all subjective, if you like yourself a substantial bass infused sound signature these will be ideal for you.

FH15 shows control for its bass but with tracks that are not recorded well it will clearly show a type of bloom with a slower decay that makes the bass note not sound as defined as it should be. If a bass note is emphasized the FH15 has greater emphasis for it than what was intended. Hence not exactly an accurate type of bass you're getting. The bass end shows the most coloration for the FH15. Just my take on it but for this closed in shell design of the FH15, Fiio could have lowered the bass emphasis by 2-3dbs for better balance and still have plenty of impact and rumble. As they are, it is mighty close to basshead territory if not actually there.

A different angle to this big bass foundation is that Fiio infused a bit of fun for their hybrid. The bass end here reminds me more of the FH3 closed in design for bass vs their higher end FH7S or FH9 hybrids making them better suited for street use.

Folks that don't mind a bit of a big woofer style bass the FH15 has that in spades so it will depend on how you like your bass. Its bass emphasis is not the tightest or the best defined. It has some beefiness to its note but has a bit of fat around that beef. In other words it is more quantity vs quality. Closed bass designs will be bigger and beefier by nature so know this before signing up for a FH15.

Overall
The FH15 is an improvement vs their prior FH5 which the tuning is loosely based off of. It has a vocal forward sound signature much like the FH5 but re-tunes that signature for the new FH15. Its weighty roomy sound is musical and has a good technical foundation. But the bass end is clearly elevated to the point it skews the sound balancing to its bass end at times. Having this much bass emphasis is nothing new for Fiio but at the same time are we going for a balanced sound? Or a bassy one? Doing both has some issues in a closed cavity.

Non bassy tracks you can hear just how good the mids and treble BAs are working together for the presentation. It is nicely detailed, rich, full weighty and musical to hear. To be fair EDM and bass genres sounds great on the FH15 which seems to be why it has the bass end it does but in going for a versatile universal sound, the FH15 seems to have a higher end mids to treble presentation with a street consumer style bass end. This works great for eclectic music listening but ends up not being the best suited for music that requires finesse and accuracy for the lower notes. A lot of folks will be more than OK with this presentation. They will enjoy it and if that was the idea behind its design, than it will be successful but somehow I wanted a bit more from the balancing of the FH15. All it would have taken was a bit of a reduction of its emphasis to be better balanced. Taken as they are, the FH15 is more of a musical fun bassy set that shows glimpses of a higher end sound. Its bass end can be enjoyable depending on the genre of music you are listening to but on the other hand can be a bit distracting on the same token.

In the grand scheme of things the FH15 is priced according to where they sit in the hierarchy for Fiios very popular hybrid line. I know it sounds like I am being very critical of the bass end here but it's just that it is ever so close to pulling off one of the best sounding hybrids for its price point. I appreciate that Fiio incorporates a universal design that tries to design the best it can be at the given price points. If you take them on a more casual, fun listening angle I think they are more than competitive and down right engaging showing they can compete with the best of the best at the price.

These will appeal to bass fans in general but somehow I feel it could have actually set the bar at the price point if it had a bit better balancing. The FH15 are clearly made for enjoying music vs analyzing and that is not a bad thing. Everyone deserves a well made beefier bassy set and there are times when I actually want a bassier IEM to listen to, especially when I am out and about. These will be excellent for those times when you want to be immersed in your music, getting your thump on wherever you may be. In that regard they will be yet another hit by Fiio. Thanks for taking the time to read.