FiiO FD3 Review

The Fiio FD3 is the company’s latest IEM and features a single dynamic driver. The magnet has a flux density of 1.5 Tesla and it has a 12mm “Flagship-level” DLC (diamond-like carbon) diaphragm, front acoustic prism, semi-open acoustic design, interchangeable sound tubes and 2.5D film coating glass faceplate. Priced at $109, the FD3 is an affordable and value for money proposition aimed at the entry-level consumer market.

fiio fd3
From FiiO

The Packaging

Having owned several Fiio products, I have found that they are always very well made and presented. The FD3 is the first of their IEMs I have tried and it is no exception. The front of the box has a line drawing of the IEMs which has an iridescent effect. It opens like a book and inside the IEMs are presented in a foam cut-out with the cable attached. Below this is a simple black box containing the accessories which are stored in a clear plastic container with a hinged lid.

In the package, it includes: the FD3 IEMs, a 4-core single crystal copper cable, 3 “Balanced” silicone ear tips, 3 “Bass” silicone ear tips, 3 “Vocal” silicone ear tips, 2 Foam tips, 2 sound tubes, 1 bass, 1 treble, a cleaning brush, MMCX assist tool & a user manual. It is a very generous and comprehensive bundle and very attractively presented.

Build and Design

The IEMs themselves are very well made, solid and compact. The cylindrical metal body is finished in a glossy grey colour and there is a gold-coloured ring around the edge of the circular faceplate which has a marbled effect and a gold Fiio logo in the centre. The MMCX socket has colour coding for channel identification and there is a vented grille on the opposite side of the housing. There is a small circular vent at the base of the nozzle which is swappable with two sets of nozzles (sound tubes) being supplied. The bass tubes (red ring) were pre-installed. 

The cable is a single crystal copper type with a total of 120 cores. It has clear plastic ear guides which are fairly tightly curved, a metal Y-split which is Fiio branded and a black metal circular chin slider. The gold plated 3.5mm 90° plug is metal with a rubberised finish. 

Fit and Isolation

Using the stock cable and pre-fitted tips (Balanced, M), the FD3 proved to be very comfortable and provided a good level of isolation although it was still possible to hear some external sounds. The fit was snug and the earpieces did not protrude from the ears. The source used was an Xduoo X20 DAP and a burn in time of 100 hours was allowed. Adequate volume was obtained and I felt there was no need for additional amplification. After trying other equipment I did find the FD3 source sensitive and that the higher the quality source, the better the result. 

Sound Impressions


Auditioned with the pre-installed sound tubes and eartips, the FD3 displayed a prominent bass and a clear detailed treble with the midrange slightly recessed. The overall tonality was on the warm side, although the timbre was authentic, and the staging was a little narrow. I then installed the “vocal” (black) sound tubes and changed to the medium “vocal” eartips. These changes brought significant improvements for me with a clearer midrange, tighter bass and a significant enlargement of the staging.

The delivery was natural and unforced with a refined quality and the effect was now dramatic, powerful and expansive with a much better balance in the frequencies. The tonality still retained a touch of extra warmth which gave an attractive bloom to the presentation and the dynamic range was particularly notable, climaxes being handled effortlessly with plenty of headroom.


The bass possessed very good extension with the lowest frequencies reproduced with clarity and high resolution and with good transient attack. The timbre was very natural and there was a satisfying weight to the notes. This provided an excellent foundation for the rest of the spectrum endowing it with an attractive tinge of warmth without affecting the speed.

Orchestral bass drums impressed with their impact and depth with ambient information clearly depicted. There was a healthy dose of rumble in the sub-bass, a lively kick in the mid-bass and only a minor bleed into the midrange. 


The FD3’s midrange revealed a natural timbre with a warm cast. Cellos and pianos displayed an attractive woody tonality, brass came over with good bite and attack and woodwind instruments retained their individual character.

Strings were reproduced with a silky quality and very good separation with bodies of strings sounding as they should, as individual instruments playing together rather than one merged sound. Male vocals had the requisite warmth and female vocals were clear and well defined. Musicality and smoothness were the keywords here. 


The FD3’s treble was deceptively extended. For an earphone with a warm tonality its treble performance was more detailed than expected and there was a total absence of harshness, peaks or sibilance, resulting in a relaxing and smooth delivery which was musically satisfying, even though it did not present details in a more overt fashion as a brighter model might.

The separation and timbre were very well judged and I never got the feeling there was anything missing. I found it was easy to sit back, close my eyes and enjoy the music. 

Soundstage and Imaging

This was perhaps the best feature of the FD3 with a wide, three-dimensional and almost holographic effect filling the space between and indeed, beyond the ears with a broad panorama of sound and atmosphere. Layering and separation were very evident and imaging precise with a good representation of stereo movement.

This cinematic style of presentation suited large scale classical works and electronic soundscapes very well but at the same time, more intimately recorded pieces received an appropriately concentrated performance, drawing you into the music.

From FiiO


Whizzer HE01 (£60)

The HE01 employs a 10.2mm DD with a 1.2 Tesla magnet, composite metal film/polymer diaphragm and the HDSS, a copper ring device designed to improve transparency and atmosphere. The sound is open, clear, and detailed with a warm tonality. The overall profile is mildly V shaped and broadly similar to the FD3, but the soundstage is not as extensive and the FD3’s midrange is more forward.

Timbre in the two is similar with the FD3 just edging it in quality. The bass quantity is similar but the FD3 is faster. The FD3’s treble is a little smoother and more detailed with a more expressive character and its delivery is more exciting and lively. 

HZ Sound Heart Mirror (£35)

Although not in the same price bracket as the FD3, the Heart Mirror’s outstanding performance justifies its inclusion here. Armed with a 10mm dynamic driver with a carbon nanometer diaphragm and clothed in a shiny silver finish, it also looks the part. It has a neutral/bright profile with superb transparency and clarity and excellent detail retrieval.

The FD3 has a warmer, more bassy profile and a larger soundstage, reproducing music with more impact. The two are very different in character, with each having its merits. Technicalities go to the Heart Mirror but both present music in an appealing way from a different perspective, the Heart Mirror more analytically and the FD3 more romantically with its heart on its sleeve. 

Moondrop Aria (£60)

The Aria employs a 10mm DD with an LCP diaphragm. It has been tuned to Moondrop’s “in-house” profile which is based on the Harman shaping but with a treble plateau set a little higher in frequency. The Aria’s timbre is less affected by warmth and is, in this respect, arguably more accurate than the FD3. There is a transparent quality with “etched” detail and, subjectively, a more extended treble.

The overall tonality is cooler and it is adept in technicality whilst remaining eminently musical. Build quality is on a par with the FD3. Honours in the bass go to the FD3 which goes deeper with more impact but the Aria has a tighter delivery resulting in a more neutral sound.

In contrast, the FD3 has a “bigger” sound and has the “fun factor” so once more, it is a contrast of personalities, with both having their considerable merits. 


Some time ago I wrote a review of an earphone with a bold and dramatic sound which brought to mind the song “Glorious Technicolour, Breathtaking Cinemascope and Stereophonic Sound” from the film “Silk Stockings”. The FD3’s character fits that description with its broad cinematic delivery and rich, vibrant presentation and has a natural sound majoring on enjoyment and entertainment.

Beautifully made and presented and furnished with generous accessories, it certainly impresses, and with a choice of tuning options, it is also versatile, adapting itself to a variety of genres. 

The FD3 is an attractively-voiced IEM which demonstrates what a well-tuned dynamic driver can do and above all, it places musical enjoyment as its priority, which is as it should be.  

Fiio FD3 Specifications

Impedance: 32Ω
Frequency Response: 10Hz-40kHz
Sensitivity: 109dB@1mW

Available from:

About Post Author

Author: Lynn Gray

Lynn has been interested in audio since the 70s when his brother brought him his first ever Hi-Fi system. Since then, he has developed an interest in portable audio when the first Walkman came out. He has been testing products for a number of years and enjoys experiencing new technology.

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