FiiO FD5 – 5th dimension

If you're looking for an IEM that boasts one of the best soundstage at any price, features powerful, clean and quick bass with excellent control as well as a clear, open an articulate midrange and a well extended and engaging natural sounding treble then the FD5 is a no brainer! If you own a good copper cable I strongly suggest you plug it to the FD5 as it will be a more relaxed yet engaging listen and if you don't it's worth spending the extra money unless you enjoy a more energetic and brighter midrange. I would stick to the larger nozzle as the narrower brings most of the benefits a copper cable brings with the downside of making the soundstage smaller and penalizing the upper treble presence and the engaging lower treble.


  • Class leading soundstage with very natural presentation and preservation of vocal presence (with larger nozzle)
  • Clean, powerful well extended bass with excellent speed
  • Well extended, natural upper treble with good presence provides excellent air and resolution (with larger nozzle)
  • Clear, open and articulate midrange with excellent bite
  • Engaging and emotional female vocals
  • Precise imaging and excellent separation
  • Scales with better sources and cables
  • Tremendous value for money
  • Excellent build quality
  • Premium packaging and accessories worthy of flagship status at a reasonable price


  • Hints of sibilance (with stock cable – with a good copper upgrade cable like Hansound Zen 8 wire, strike this)
  • Energetic upper mids can’t lead to some harshness in hi hats and snares (with stock cable – with a good copper upgrade cable like Hansound Zen 8 wire, strike this)
  • Male vocals lack power (with stock cable – with a good copper upgrade cable like Hansound Zen 8 wire, strike this)
  • One set of tips (triple flange) only for the narrower nozzle

Product Page :
Price : 319$

Fit, Build & Isolation

The FiiO FD5 features a stainless steel faceplate and an unspecified chrome finished alloy that is probably aluminium to avoid the FD5 to be too heavy (thinking IER-Z1R there) and each units weight 11g and are very comfortable to wear.

The faceplate features a grille that is part of the semi-open design of the FD5, note that on top of the front grille the shell itself does have a small venting port at the base of the nozzle as you can see on the right unit below.

The FD5 has color coded MMCX sockets providing a visual cue that can prove helpful for people with poorer vision and that’s a nice touch I always appreciate.

A lot of thought has clearly gone into the FD5 design, and the FD5 also offer a unique couple of nozzle that have an impact on tuning (not unusual) but also on fit (with different nozzle diameter). FiiO calls them interchangeable sound tubes and as we’ll see it has an impact on how the FD5 sounds.

As you can see the narrower nozzle is much narrower than the default larger one which the FD5 comes mounted with. Note that aside from the triple flanged tips provided all the other tips are meant for the larger nozzle. I think this is an oversight and I would have appreciated more options for the smaller nozzle although it’s fairly easy to pick up SpinFits or many other brands of tips for the smaller nozzle.

Last but not least FiiO wasn’t cheap on the stock cable which is an 8 strands of monocrystalline silver-plated copper cable with a new interchangeable plug system developed by Fabrilous. As you can see it’s pretty easy to operate with a screw and click system. I always appreciate the ability to run an IEM balanced and I switched mine to 4.4.


There is no need for introduction as FiiO is so well know among audiophiles, suffice to say the brand is growing its upper end offering and putting a lot of effort into it the top spec’ed M15 DAP and the recent FA9 and FH7 IEMs as well as the EM5 earbud. The FD5 arrives as the dynamic flagship of the brand and I expected a higher priced IEM to be honest.

FiiO clearly put a lot of R&D effort into the FD5 design, not so much into the 12mm beryllium coated driver as it’s a common technology but rather with a pretty elaborate acoustic design :

The goal of both the rear volcanic field and front acoustic prism is to reduce distorsion and facilitate the flowing of the sound waves and ultimately sound quality. The semi-open design also alleviates pressure for a fatigue free listen.

The tuning goal of FiiO for the FD5 is clearly stated as based on Harman target response curve aiming at a relaxed and natural sounding IEM :

I have never been one to stop at frequency response curve to figure out how an IEM actually sounds as many things come into how an IEM sound that don’t reflect there (attack and decay of notes being one very important one, acoustic properties affect soundstage, etc…). On top of this there should be two response curves for each nozzle and I assume this is the response curve for the larger nozzle.

So how does all those design features translate into real world listening and sound quality?
Is the FD5 consistent with its tuning goal of relaxed and natural?

Let’s check this out!

Note : All impressions are based on the larger nozzle and balanced tips by default, a note of narrower nozzle and tips influence on the baseline sound is specified and highlighted in italics.


The first thing that struck me was how massive the soundstage is : aside from the Audeze LCD-i4 (arguably not an IEM) or the IE800/800S I had not heard such a stage on an IEM. If you’re a soundstage addict then rejoice : it’s exceptional and among the top performers with astounding width, great height and excellent depth. Listening to the FD5 almost feels like a full sized headphone. Color me impressed. The stage size is more elliptical than spherical as I found depth to be a little less impressive than width and height but it’s not a minus to me. The stage is realistic and coherent and it also helps vocals remain clear and focused rather than hollow and distant. Imaging is very precise. Switching to the narrower nozzle, the stage is still excellent but not exceptional and you loose quite a bit compared to the larger nozzle.

The second thing that struck me was the bass power although it went from bombastic bass-head territory out of the box to a very powerful but not overshadowing bass after proper burn in. It’s a clean, tight and fast bass with excellent control but that was to be expected with a semi open design. Switching to the narrower nozzle, the bass clearly gains in power and presence with more slam factor that will rejoice bass heads.

Then the third thing was the upper mids energy and upper treble presence. This is where I feel the relaxed part of the tuning is a bit off but at the same time compared to the Harman target response FiiO advertised curve showed potentially some upper mids peaks were apparent as well as more treble presence. Also, depending on the source and cable this will be more or less sensitive. I immediately noticed the upper mids energy with the DX160 while the R8 was much smoother. Switching to the narrower nozzle the upper mids are less energetic : the FD5 is clearly brighter with the larger nozzle. Tips will also come into play and bass tips will be more relaxed than the balanced and vocal tips are more energetic. You also loose upper treble presence with explains the fact there is less air and smaller soundstage with the narrower nozzle.

Now, let’s dive a bit deeper!


The FD5 bass is definitely one of its highlight, and it doesn’t disappoint.

Sub bass extension is excellent with great presence, especially with the “bass” labelled tips that add just a tad more presence. Semi-open design don’t always fare well there but the FD5 has great physicality and a deeply seated sub bass that is never saturated. L’impératrice “Erreur 404”, just like Ayo “Throw it away” sub bass rythm are quite saturated in the mix and most IEMs will have just a bit too much exhibiting some blooming but the FD5 retained perfect control no doubt thanks to its semi open nature. Okvsho “Algoriddim” quick sub bass beats are snappy and controlled with impeccable rhythm and one of the most impressive portraying of that track. Switching to the narrower nozzle, bass presence is increased with a more physical sub bass but a bit less controlled with some hints of blooming and saturation.

Mid bass has good slam and packs a lot of details, drums in Fink “Resurgam” are every bit as hypnotic as they’re supposed to be and the FD5 really impressed me for this track is often a bit too darkly portrayed and looses some detail in the percussions. The sheer size of the FD5 stage also helped there with separation when the tracks get busy around the 4 minutes mark. Marian Hill “Differently” intro is an interesting track where quick heavy electric bass and sudden claps pop and vanish into thin air and clearly the FD5 shows how snappy its bass note attack can be and how clean and quick decay is as well. This track clearly stood out compared to the wide array of IEMs I have reviewed so far. Switching to the narrower nozzle, mid bass presence is increased with better mid bass slam but a bit less controlled and layered presentation. Bass feels less agile with less snap and overall speed. Rolling cable to my Hansound Zen 8 wire full copper cable the bass gains quite a bit of presence and depth.


The FD5 mids are clear, open and articulate. Looking at FiiO advertised curve I would have figured a fuller sounding unit as the lower mids were north of the Harman curve. It might be the semi-open design but while it’s not thin per say it’s certainly not a full sounding midrange with weighty notes and bold portraying of instruments. Overall timbre wise I found the mids are a tad brighter than what I consider neutral with a clear upper mids tilt. Instruments separation is superb, also thanks to its sheer stage size, and the FD5 has no issue with larger ensembles and delivering a very coherent message on those tracks.

As hinted in the general description, the lower mids are rather lean and the strong bass foundation is a good thing to bring heft to the FD5. This shows for example in how the FD5 is portraying the double bass or the guitar bass : the bottom is well seated but the attack is a bit weak and I find myself wishing for more fullness. This was quite apparent in Carlos Henriquez “Cuchifrito” or Blue Mitchell “Na Ta Ka” were I didn’t find as much enjoyment as I usually do with stringed bass on those tracks. Rolling cable to my Hansound Zen 8 wire full copper cable the mids are significantly fuller while not loosing any of the stage size and resolution, the missing weight is back to satisfying levels. Switching to the narrower nozzle with the stock cable things are also better with a fuller bodied presentation although it’s not thick or heavily weighted either it carries a bit more meat. On the flipside you loose quite a bit of separation, bite and the midrange is less articulate.

The FD5 upper mids play a big role in its signature as it’s among the more energetic part of the range along with the bass. This is a clear midrange with significant bite that stays on the safe side for me but might be a bit too much for some especially with the balanced and vocal tips. I know tracks like Hank Levy “Whiplash” sometimes cymbals and snares had me wince and bring me over the edge of my personal sensitivity. The bass tips will tame especially the hints of sibilance that can occur on female vocals and with the default nozzle the bass tips has been my preference. On the flipside the FD5 has delightful crispness and alto saxophones and clarinet have delicious bite and brass instruments in general are lively as they should with excellent reproduction of timbres. This works wonders on Jazz. Electric guitars are just as satisfying and I enjoyed Spin Doctors “So bad” and The Pixies “Where is my mind” a lot on the FD5. Rolling cable to my Hansound Zen 8 wire full copper cable the mids are significantly smoother while not loosing bite, even Hank Levy “Whiplash” is perfectly safe : peaks are smoothened out.

Vocals on the FD5 are very clear and pack a lot of details with good emphasis. As hinted before, the vocal positioning is forward relative to the stage size depth is not as important as width and height although it’s relative positioning : it’s not an intimate vocal positioning either. Given the upper mids tilt and safe lower treble, female vocals and higher pitched male vocals (like James Blake “Vincent”) are more engaging with proper intensity and energy while the lower register male vocals (or female like Itzo Fitzroy) lacked power and grit at least to my taste (Jack Savoretti “Written in scars” certainly sounded a bit hollow). Sibilance is generally not an issue especially with bass tips but the FD5 is not exempt of sibilance for example Gabrielle Alpin “My mistake” or Hollidays “Sensible” or Freya Riding “Lost without you” exhibited some hints of sibilance although to be honest not a deal breaker for me. This was more sensitive on iBasso DX160 than Hiby R8 and Lotoo PAW S1. I think the FD5 will pair well with warmer and smoother sources. Rolling cable to my Hansound Zen 8 wire full copper cable the male vocals are much improved with more power and grit and the FD5 is quite a different performer there.


The FD5 treble is clearly aimed at providing air and resolution with its upper treble tilt. Lower treble has good energy but it’s not that lively and it’s quite safe. A wise choice given how powerful the bass and energetic the FD5 upper mids are, any other choice would have made the FD5 tiring.

Lower treble is conservatively tuned in the sense that it shows restraints in terms of its energy, while presence is good. It’s an engaging lower treble but not an exciting one, and again the semi-open design has its downsides : I wouldn’t have minded a bit more weight to the treble notes especially on piano notes. This also shows in Stan Getz “Maracatu-Too” where Jose Paulo and Luiz Parga chime like percussions are beautiful but I would have liked a bit more treble energy and weight which would have made it more engaging.

The FD5 upper treble has great presence and is very well extended and its decay is very natural with excellent transient speed. This is a big factor into FD5 excellent air and very good resolution as well as its precise imaging. Jack Johnson “Staple it together” was a testimony to the FD5 speedy and well extended treble as well as Fleetwood Mac “Never going back again”.

Select Comparisons

If you’ve read my ISN H40 review but also most reviews and impressions you know ISN H40 is one of the kings of the price segment and the best value for money I reviewed last year along with Penon Orb. The H40 is a warm, engaging, fun and punchy IEM with a huge soundstage and good resolution. It’s certainly the contender for the FD5 in terms of soundstage and bass.

Soundstage wise the H40 is a very good performer, this is a huge soundstage with a coherent image and remarkably wide but more importantly unusually tall and deep stage. But the FD5 is just in another league yet and that’s only fair given its semi open nature. Stage size is yet bigger reaching elite levels but the image is more precise thanks to much better separation. There is simply more space around instruments and on top of it resolution is higher on the FD5.

Bass. This is the showdown you’ve been waiting for. The H40 boasts massive bass presence with very good sub bass extension but the FD5 goes lower. It has a more physical presence than the FD5 but that was to be expected given the closed nature of the H40 versus the semi open FD5. On the flipside the FD5 is in another league in term of control but also it has a significantly faster bass and is able to keep up with faster paced music. The H40 has good control but the FD5 is just sublime there and both sub and mid bass are cleaner. The H40 has a bit of a more “romantic” bass, with a softer attack and a bit longer decay. The H40 has richer textures, but the FD5 offers more detail there.

The H40 mids are probably the main differentiator with the FD5. The ISN H40 midrange is full bodied, with strong lower mids foundation that definitely give it a significant warmer tilt. The upper mids while not recessed are a bit dipped and lack a bit of bite but then rise again to provide good sizzle on cymbals and crispness to snare drums. The FD5 have much leaner lower mids and more bite, making it a brighter proposition. The H40 is smoother, thicker and mellower while the FD5 is more open, articulate with better separation.

Treble wise the H40 extension is fairly decent and there is good upper treble presence, providing air and refinement to the treble presentation with nice overtones. The lower treble avoids sensitive areas while providing good energy, in fact a bit more than the FD5 and also the note weight is greater on the H40 making the lower treble both more energetic and articulate. The FD5 on the other hand is much more extended and the upper treble has more presence which makes the FD5 more open, airy and with more precise imaging as well as significantly more resolving.

Meze Rai Solo
The Solo is a natural comparison to the FD5 as it’s a dynamic, in the same price segment. If you’ve read my Rai Solo review you know it’s a clear, energetic, open sounding IEM. The Solo has superb brushed stainless steel build that feels more sturdy than the FD5 as contrary to the FD5 who only has stainless steel on the faceplate, the Solo is full steel. Brushed steel is also much less prone to scratching, the FD5 are more shiny but also more fragile as hinted by the shell divider on the FD5 carry case.

But let’s get down to sound. For the sake of the comparison I used the FD5 cable and the same tips on both units. The first thing that struck me is how bigger the soundstage of the FD5 is compared to the Solo. Not that the Solo is narrow or small, just the FD5 has a much bigger stage in all direction but height and depth are just so much bigger on the FD5. The Solo sounds almost intimate by comparison.

The Solo has well textured, highly detailed bass with a fair sub bass extension but it lacks physicality and for a dynamic is a bit disappointing. It’s more of a reference bass, in your head rather than in your gut. The FD5 on the other hand packs very good sub bass extension with a lot of power and control. It has similar level of detail but much more presence in the sub bass but also mid bass. The FD5 has a better sense of rhythm, more slam and toe tapping factor.

The Solo’s mids are clear, articulate with very good separation and air, timbre is accurate and the presentation is forward. Lower mids are not thin, but do take a back seat to the more prominent upper mids. Although it’s a similar philosophy, the FD5 has a less pronounced tilt towards upper mids and the Solo has yet more bite and is therefore the brighter of the two. Again the FD5 has more separation and articulation by way of its immense soundstage and will be better suited for larger ensembles.

The Solo’s treble is definitely key to its signature, it has very good extension and provides good air and very nice resolution as well as great energy. This is one key difference to the FD5, lower treble energy is greater on the Solo providing more excitement but also notes have more weight and I felt the Solo did a better job on piano tracks. On the flipside the FD5 has more upper treble presence but also is more extended. There is more air and resolution is one step up. The FD5 retrieves more detail and its transients are faster although the Solo is no slouch.

Overall the FD5 is more balanced than the Solo, for starters its bass presence alone gives it a better pace, rhythm and timing than the Solo but it also balances the upper mids and treble. The FD5 is more grounded and physical. The Solo invites a more analytical less engaging listen bass wise. The FD5 midrange is fuller, with more lower mids presence and less prominent upper mids as well as less forward vocals providing more stage depth. Treble wise the Solo is more energetic and engaging but also more fatiguing of the two. The FD5 is more relaxed but also more refined.


I have reviewed quite a few IEM but it’s my first FiiO product review although I used to own a X7 II back in the days and am familiar with the brand. The FD5 had a lot of interesting aspects to me as I am a dynamic driver aficionado and I must say the semi-open and advanced acoustic design and the tuning goal as well as reasonable price had me impulse buy the FD5.

Did the FD5 hold its promises? Yes, and then some in terms of value for money. Soundstage alone makes the FD5 special, as I said aside from the LCD-i4 or IE800/800S I haven’t heard something like it. That’s pretty select company. The FD5 also boast impressive technicalities in the price range, with excellent resolution and imaging. The only minor gripe I have is while the tuning is definitely natural sounding it’s not relaxed at least not in my book : the upper mids energy and bite alone means the FD5 will command your attention and depending on sources, tips and cables it could be too much. While the stock cable is great in terms of build and performs well, in my opinion it brings too much upper mids energy and switching over to a good copper cable like Hansound Zen 8 wires was a revelation. The FD5 gains yet a bit more stage size and bass a bit more power, but more importantly the midrange is both fuller sounding and more relaxed restoring balance to the mids that is much brighter with the stock cable.

If you’re looking for an IEM that boasts one of the best soundstage at any price, features powerful, clean and quick bass with excellent control as well as a clear, open an articulate midrange and a well extended and engaging natural sounding treble then the FD5 is a no brainer! If you own a good copper cable I strongly suggest you plug it to the FD5 as it will be a more relaxed yet engaging listen and if you don’t it’s worth spending the extra money unless you enjoy a more energetic and brighter midrange. I would stick to the larger nozzle as the narrower brings most of the benefits a copper cable brings with the downside of making the soundstage smaller and penalizing the upper treble presence and the engaging lower treble.

Listening notes
I spent approximately 60 hours with the FiiO FD5, listening on Hiby R8 and iBasso DX160 using the stock cable and Hansound Zen 8 wire upgrade cable balanced. 

The FiiO FD5 are a paid unit purchased from FiiO Store at retail price.
As usual, this review is my honest opinion.


  • HB5 Hard carry case with divider
  • Set of 3 balanced, 3 bass, 3 vocals, 4 foams and 3 triflange eartips
  • cleaning brush
  • 8 strands of mono crystalline silver- plated copper cable, Cable length : 120cm, Connector: MMCX, Plug Terminations : 4.4 mm TRRS Balanced, 3.5 mm TRS Single-Ended, 2.5 mm TRRS Balanced


  • Driver : 12mm Beryllium-coated diamond-like carbon (DLC) dynamic driver.
  • Frequency response : 10 – 40000 Hz
  • Impedance : 32 Ohm
  • Sensitivity : 109db/1mW

7 thoughts on “FiiO FD5 – 5th dimension

Add yours

  1. Hello. Nice review! Could you kidly compare soundstage, imaging capability and detail retrieval of Fiio Fd5 with Dunu Sa6 and Tansio Mirai TSMR-5?


    1. Hi Keyk, I have a big backlog but in a nutshell though : SA6 is fuller sounding with a warmer tilt than FD5, FD5 has a much bigger soundstage than SA6. On resolution SA6 is better although FD5 pushes the detail with more upper treble presence. Imaging SA6 is more precise but FD5 has a bigger image making for increased separation.

      Vs TSMR-5, FD5 again has bigger soundstage and I would say imaging is a close call although bigger stage and increased separation. FD5 has better resolution but not by a big margin.

      Hope this helps!


      1. Hello. Thank you for reply. Some more questions 😉 Which one, FD5 or SA6, sounds better for you from ibasso Dx160?

        Do you think that Yinyoo or KBEar copper cables could work with FD5 in the way you have described for Hansound Zen?


        Liked by 1 person

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