FiiO FD15 HiFi IEMS – Magnalium Dynamic Driver Rise
FiiO FD15 is a $159 USD pair of IEMS or In-Ear Monitors with a Magnalium diaphragm DLC gasket driver at the heart, Deep bass and Midrange voicing, coming with a 1.5T Magnetic Flux for the driver magnets, and 316L Stainless Steel Shell to impress you with their sound. Today we will review the FD15, going in-depth with the analysis of their sound and whether they make a compelling purchase at the moment of writing this review.
Introduction
FiiO has always been a popular brand but these days their popularity has skyrocketed, as the company is now releasing DAC/AMPs that look like Cassette players, Vinyl players, and even speakers like the SP3 BT that we reviewed recently. Thanks to their popularity, FiiO products are available for purchase from a multitude of sources, including electronics stores, local shops, Hifi shops, Amazon, Aliepxress and basically every single location you can think of. It is a good idea to purchase from Authorized dealers for warranty purposes, so Amazon and Aliexpress are preferable. As an Amazon Influencer, I earn from qualifying purchases, and using the purchase links in my reviews helps me maintain this website and Youtube Channel. Huge thanks to FiiO for providing us with the sample for this review.
PROs – Cohesive sound, with a warm and bassy tuning, strong and powerful male voices as well as soprano female voices, strong bass guitar reproduction and rendering with a bloomy low-end and musical guitar rendering. Excellent build quality and a top notch cable that is modular, along with a superb package.
Cons – Contralto female voices are a bit recessed, bass can be a bit too bloomy at times.
Product Link
Amazon – https://amzn.to/3NMMTke
Aliexpress – https://s.click.aliexpress.com/e/_DcQTpgd
Build Quality/Aesthetics/Fit/Comfort
While when reviewing products from certain companies I can’t find enough info, FiiO designs their IEMS in-house and their marketing department knows that there is no reason to keep secrets, so we get to know every intimate aspect of FD15 from the product paperwork. Starting with the driver at the heart of the beast, we have 13.8mm dynamic drivers, with a high-end diaphragm, and a W-Shaped gasket, which increases the movement area by 30%. There is a frontal acoustic prism which has adaptive phase adjustment, enhancing high frequency diffusion. The driver has a 8.6mm voice coil, which is 40% longer than that of the predecessor, and this boosts their driver power by 78%.
The magnet volume is 69.5% larger, having up to 1.5T of magnetic power, and compared to FD5, the effective diaphragm area has been increased. The Tesla Valve Bass enhanced acoustic technology is also implemented, and FiiO uses Magnalium Diaphragm DLC Gasket, which is a blend of magnesium, and aluminum, offering a high hardness and low distortion.
FiiO implemented a smart acoustic design, with their F.T.B.S Tesla Valve Bass Enhancement, a special selection of tubing and shapes inside of the IEM that alternate the airflow from the outside and from the inside to allow the internal pressure to be equalized quickly, but the sound to flow from the inside to the outside like a viscous substance, creating a deeper and more powerful bass. FD15 is designed to be voice-centric, having a noticeable boost on the midrange compared to the bass and the treble, in the measurements taken by FiiO.
FD15 has a 6.7 degrees of nozzle angling, to achieve the best comfort possible, and FD15 features curved MMCX connectors, and optimized frontal contact surface. The shell of FD15 is made of stainless steel, and it is a 316L medical-grade stainless steel, with PCD electroplating, while the cable is a Furukawa Monocrystalline copper + Furukawa Monocrystalline Silver-Plated Copper braided cable, with detachable jacks, supporting both 4.4mm balanced connectors, and single ended 3.5mm connectors. The cable is the same as the separately sold LC-RC 2024 cable. FiiO put two colors on the market, Obsidian and Racing Silver, and to further allow customisation, FD15 comes with two nozzle options, red for luisher and warmer sound, and the Black Nozzle for a brighter, more brilliant sound.
At the technical level, FD15 sports 12 grams of weigh per IEM, and a Sensitivity of 112dB/m@, with an impedance of 32 OHMs. Subjectively, FD15 is substantial, the IEM shells are amde of metal and they feel a bit heavy inside my ears, but they are made very well, the angling of the bore along with the cable provide an excellent comfort. As per my usual review formula, I have replaced the default tips with a pair of transparent sounding eartips – ddHiFi ST-35, as FD15 sounds really natural and feels natural with them. The default ear tips are of a good quality, but are on the solid and hard side of things. The passive noise isolation is excellent, between 20 dB and 30 dB, while the leakage is almost zero.
Sound Quality
Pairings – To drive the FiiO FD5 I have paired them with a large collection of sources, including iBasso PB5 connected to iBasso D16, HIDIZS S8 PRO Robin, Creative Sound Blaster AE-9, iFi Hip-Dac 3, Kaei TAP-1 DACs, Burson PlayMate 2, and HIFIMAN EF400. All of those sources can drive the FD5 just fine, and I found them to be more than suited for FD15, it is an IEM that’s ultra easy to drive, there’s no need for too much power, but FD15 is sensitive to noise and a controlled, clean source would work best.
Overall Signature – Sonically, FD15 is a warm-natural sounding IEM with a big and warm, silky bass, a natural voice that’s sweet and pleasing to the ear, and a smoother treble. At louder volumes, the bass dominates the sound a bit more, while at lower volumes, the sound is more balanced. As I write this review in two separate instances, I came back to write about the sound two weeks after writing the technical part (a little bout of otitis was involved and this was not a voluntary decision), but I completely forgot that FiiO actually described the sound of FD15 accurately, it is a bass and mid centric IEM with a strong voicing and a warm bass.
Bass – The low-end of FD15 is deep and warm, similar to that of FH19, but FH19 is deeper and more powerful, while FD15 has a slower, warmer bass that is a bit bloomier. This creates a fairly warm and fuzzy, romantic presentation. Most of the bass energy is found around 60 Hz, with the bass on the lower end having less presence and focus than this upper bass. The sound and presentation of FD15 has a tendency to give all instruments a strong presence, body and a powerful sound. This is relevant especially for bass guitars which sound extremely detailed and present, more audible than with most IEMs in the price range.
Midrange – We have a good balance between the lower and upper midrange, as FD15 emphasizes both male and female voices equally, and gives both a strong color, pleasing sound and a smooth, natural texture. Guitars are on the blended side, as the texture is not analytical and does not stand out too much. Sharp and high-pitched female voices sound sweet and brilliant, while deep male voices sound powerful, with a little dip being apparent in the middle part, as contralto voices have less strength than soprano voices. The two resonance mechanisms inside of FD15 are quite apparent and the bass resonance, along with the lower midrange resonance is stronger than the middle and so is the sharper treble resonance, which is to be expected from the dynamic driver.
Treble – I often think it is not that useful to judge the treble performance with the brightest songs I have, but with FD15 this may just be necessary as with smoother songs, or even natural sounding music, the treble is softly rolled off, which means lower in presence than the midrange, without a hard roll off. This means there is extension and air, but it is not as loud as the main midrange presence. Air is present and so is extension, as FD15 has the ability to create a fairly crisp cymbal crash when the song requires it, but it will not be enforced by default and most music is quite fatigue-free.
Dynamics – I decided to replace the dynamics composite part of my reviews, with a separate part dealing with dynamics and handling of busy complex tracks. This is because a dynamic range is different from dynamics handling and FD15 struggles a bit when the song is busy and when the mix is too loud / dynamically compressed. This being said, it is still very enjoyable, thanks to a fair instrument separation and natural blending of the instruments for classical and rock music.
PRaT / Textures – FD15 has a fairly natural-relaxed texture presentation, with the most texture and clarity being present in the bass, as FD15 reveals a lot of body and low-end presence for all instruments it plays. The midrange texture presentation is fairly smooth and silky, while the treble texture is crisp, but the treble volume is low and you never hear too much of it, which means the textures are also fatigue-free.
Volume Control – FD15 tends to become slightly more forward with higher volume, but it doesn’t register an increased distortion or a lower resolution when you pump the volume, instead always having a really clean and fatigue-free sound. The THD is particularly low for the price point, as you can literally pump the volume up to 120 dB with very little added THD.
Soundstage – A big part of purchasing FiiO FD15 is the wide and holographic projection of the instruments, while keeping the instruments blended and not too cut apart. This whole tuning creates a fairly cohesive sound, and the single dynamic driver has the same speed and tonality for all instruments, creating what can be considered a warm, cohesive image with a wide soundstage.
Value and Conclusion
There’s just so much competition in the entry-level range, but FiiO always manages to stay competitive, and FD15 has extreme value, it comes with a modular cable, excellent comfort and build quality, and plenty of resolution / sonic performance for the price point. A good cable costs more than FD15 costs with a modular, high-quality cable.
At the end of the day, if you’re looking for a pair of IEMs with a natural – warm – bassy sound, a wide soundstage, good comfort and a reliable build quality, along with a beautiful design, FiiO FD15 is your metallic companion and will serve well across any music style you may pump into it.
Product Link
Amazon – https://amzn.to/3NMMTke
Aliexpress – https://s.click.aliexpress.com/e/_DcQTpgd
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Full Playlist used for this review
We listened to more songs than those named in this playlist, but those are excellent for identifying a sonic signature. I recommend trying most of the songs from this playlist, especially if you’re searching for new music! The playlists are different for Spotify, Tidal and Youtube, and based on the songs I enjoy and are available on each!
https://www.youtube.com/playlist?list=PL_cjBXGmwSHSdGcwuc_bKbBDGHL4QvYBu
https://open.spotify.com/playlist/5J3oloz8Riy9LxEGenOjQ0?si=979ba4f082414be7
https://tidal.com/browse/playlist/330fd544-8e5b-4839-bd35-676b2edbb3d5
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