FiiO F9 Hybrid 3-way In-ear Monitors - Reviews
Pros: Great extension both sides, Amazing Price, Excellent Comfort, Excellent Package, Excellent Overall Value, Fun V-Shaped Sound, Strong Bass, Good Sparkle in the treble, Clear sound
Cons: Not a direct con to F9, but F9Pro by FiiO is a great IEM as well, and not much more expensive
FiiO F9 - Emotional Affordable Audiophile

FiiO F9 is an amazingly good IEM produced by FiiO, while they tried to bring as much quality they could, at the lowest price point it was possible. After tinkering with many designs, they managed to create one nifty little IEM.


FiiO is a very well-known company from China, which has been known for years, for keeping their customers close to their hearts, for organizing tours for their amazing products, and for bringing some of the best innovations in the DAP world when they first created their FiiO X5 and X5ii models. FiiO started producing IEMs with their first few models, like FiiO EX1, which were made together with another great Chinese company named Dunu, but their latest models are produced by FiiO themselves, offering a good sight into what FiiO has been up to lately.

It should be noted that I have absolutely no affiliation with FiiO, I am not receiving any incentive for this review or to sweeten things out. This review is not sponsored nor has been paid for by FiiO or anyone else. I'd like to thank Sunny from FiiO for providing the sample for the review. The sample was provided along with FiiO's request for an honest and unbiased review. This review will be as objective as it is humanly possible, and it reflects my personal experience with FiiO FiiO F9. Every opinion expressed is mine and I stand by it, the purpose of this review is to help those interested in FiiO F9 find their next music companion.

About me


First things first, let's get the packaging out of the way:

FiiO has always been lovely with their package, and F9 is a standing proof of this. They packaged F9 in the same fancy package as they wrap their Flagship Devices, like FiiO X7mkii, which we recently reviewed.

F9 comes in a dandy-elegant-looking box, with a black and red color, and a smooth surface. You can find a beautiful rendering of F9 on the front of the package, along with some useful information on the back of the box. FiiO includes their authenticity sticker on the top of the box as well, ensuring you that you're always protected from counterfeit items, and that you're using the FiiO quality. The list of items included in the box is longer than most IEMs at this price point.

Inside the outer box, you can find a matte black cardboard box, which serves to protect F9 and their package. Within that box, you can find FiiO's carrying box, a beautiful, glossy box, made in the same style as the well-known and Pelican boxes. Next to it, there is a small cardboard compartiment that includes the 3.5mm SE cable, and the extra 2.5mm Balanced cable for F9.

Inside the Glossy Carry-Box you can find The F9 IEM bodies seated in a foam cutout, next to a wide selection of tips for F9. The inner part of the FiiO Carrying case is rubberized, so it does an amazing job at protecting F9 during transport.

The packaging is complete and has an amazingly high number of extras for a IEM priced as low as F9, making it an amazing unboxing experience and an amazing overall deal.

What to look in when purchasing a new IEM

Technical Specifications

Build Quality/Aesthetics/Fit/Comfort

After having experienced the fit and comfort of some of the world's greatest IEMs, I am happy to now feel what FiiO brings to their fans and supporters, especially since they had a lot of time to refine and develop F9.

Starting with their outer appearance, F9 is sleek and elegant, with a slightly matte surface, having a wing-like texture on the outer part of the IEM shell. The cables sport a tight and secure MMCX connection that has proven to be quite good at withstanding long-term usage. The inner part of the IEM body sports two tiny holes (vents) that help F9 breathe while in usage, defending against the typical void of only-BA setups. Since F9 has a dynamic driver in their setup, they require this vent for their dynamic driver to work its best.

FiiO F9 comes with two cables, one smooth, with a microphone / remote, ear guides, and ended in a 3.5 SE connector, and the other cable ended in a 2.5mm Balanced connector, being braided and feeling a tad supler than the SE one.

When it comes to the comfort, F9 is one of the most comfortable IEMs out there, having a somewhat deeper fit, excellent ergonomics, and a very good selection of tips included by FiiO.

Not only the comfort is excellent, but F9 also provides excellent isolation from the outside noise, being one of the few IEMs that can compete with fully sealed solutions without being one. The highlight of their comfort is their ability to just disappear in your ears, at the same time making you forget about your surroundings. F9 is a quite nice IEM when it comes to also staying in your ears for hours in a row, being comfortable even after five - six hours of continuous usage.

Sound Quality

FiiO F9 has quite a vibrant, revealing and lively tuning, with an emphasized low end, that has a natural decay to its bass, a slightly recessed midrange, and an enthusiastic top end with a bit of an added sparkle in the 7-8kHz area. Their resolution is fairly good for this price point, being able to reveal quite a bit of the hidden details in your music, all while having a very good timing and keeping a fair naturalness through their signature.

F9 tends to have excellent extension on both ends, especially for this price point, having a signature that is to fall in love with.

All sonic impressions have been taken with FiiO X7mkii, which we reviewed here:


The bass of FiiO F9 is quite deep and goes down low, the sub-bass being able to truly rumble the listener, without bleeding into the mids or overtaking the sound. The bass is slightly enhanced in the mid-bass, giving good weight to each musical note, and adding a bit of impact to the sound, once again, without bleeding into the other sonic aspects and without taking over any other part of the song. The bass feels balanced with the rest of the sonic spectrum. One can easily start to shake their head or entire body while listening to FiiO F9, the bass having a tendency to enhance the listener with a sweet emotional response.


FiiO F9 has a sweet and delicious midrange that places an emphasis on the emotional connection and the lively feeing of each song, being excellent at giving music a vivid and lively feeling. The lower midrange is slightly recessed, giving F9 a bit of space to breathe, all while keeping the whole signature full and rich. The texture of the midrange is quite excellent, F9 being good at providing a look into the detailing and textures of the music it is playing. The upper midrange is slightly more elevated in comparison to the lower midrange, giving music an excellent emotion and portrayal, F9 giving both female vocals and violins a bit of magic with its emotional sound.


The lower treble of F9 is quite nice as well, having a nice resolution and quite amazing revealing abilities. It grows a bit more enhanced at the 7kHz area, giving cymbals a bit more bite, and acoustic music a bit more magic, a bit like how RE800 from HIFIMAN does. This doesn't make F9 harsh or sibilant in any way, and that lower treble enhancement stays within what is quite enjoyable with most music, especially if one enjoys a bit more sparkle in their music. This little peak can easily be EQ'ed with most sources, being something that can be attenuated if the listeners prefers a smoother sound to their music.

The upper treble extends fairly well up top, providing enough air for instruments to breathe, having a nice resolution, especially for this price point.

The treble makes micro-details quite evident, and it gives a slightly longer trail to cymbals, providing a very clear and accurate sound. Acoustic guitars have a really nice bite and definition, especially when it comes to metal-strings acoustic guitars. Metal music is fully enjoyable and most music sounds rather lively and lovely through them.


The soundstage of F9 is quite good as F9 is not an intimate IEM, their soundstage instead extending in all directions, providing really good spatial cues. The soundstage has a bit more width than it has depth, giving F9 a wide feeling to them, while not being the most accurate in describing the depth or distance from which a sounds comes from. Even so, most music is quite enjoyable, and especially electronic music gives an amazing 3D experience with F9, and considering the comfort and the isolation, the final result is extremely enjoyable.


The ADSR/PRaT characteristics of F9 are quite good for this price range, music having a fairly good attack and decay for each musical note. Fine textures in synths are revealed nicely, and for the price point there is absolutely nothing to complain about.

Portable Usage

FiiO F9 is extremely portable, not only because they don't require any extra amplification above a typical smartphone, but they are extremely comfortable and portable as well. Having their own dedicated high-quality transport case surely helps F9 stay fresh even while in unfriendly environments, and the excellent comfort and isolation make F9 one of the best IEMs to take out on a walk.

There is a nice sense of value FiiO adds on F9 by adding a high-quality balanced cable, and that one is quite portable as well, being braided and quite flexible, just like their default cable.

The provided selection of tips are enough to fully enjoy F9, thing which is quite rare as I usually prefer using SpinFit tips.

The volume requirements of F9 are within what most smartphones and tablets can output, but their sound is quite a bit better while using a dedicated source.


FiiO F9 vs Dunu DK-3001 - Starting with the bottom end, F9 has similar amounts of bass when compared directly to DK-3001. The midrange is quite similar in presentation as well, while the top end tends to be somewhat similar as well, DK-3001 having more extension, resolution, detail and being a tad smoother in the long run.

FiiO F9 vs FiiO F9Pro - F9Pro is the bigger brother of F9, with improved Knowles Drivers, although they are almost double F9's price. F9 Pro has the same dynamic driver inside, so the bass amounts and qualities are quite similar with F9, but the midrange and the top end feels more vivid and lively on F9Pro, the high end extension being quite noticeable better on F9Pro.

FiiO F9 vs iBasso IT01 - iBasso IT01 tends to have similar sub-bass amounts when compared to F9, IT01 has considerably more mid-bass amounts, sounding fuller and warmer than F9. The top end is smoother on IT01, although it also has a nice bite and definition. The soundstage is deeper and wider on IT01. Both are excellent IEMs at this price point. F9 being more V-Shaped with a less thick sonic signature.

FiiO F9 vs MO MZero - MO MZero is a full sized BT Headphone that is priced at a similar price point as F9. The comfort is slightly better on F9 for my ears since MZero is a bit smaller in its pads. The sound of MZero has more bass amounts, with more impact, and a thicker sound in general. The midrange is similar, with more clarity and emphasis on the upper midrange for F9. The treble is more enhanced on F9, being smoother and having less extension on MZero. Of course, they are different products, but given their price point, MZero makes an interesting competition for the 100$ Market.

FiiO F9 vs Astrotec AM850 - AM850 makes a serious rival for F9, having a somewhat similar signature, with a slightly less recessed midrange, with more sub-bass hit and a larger soundstage, sounding a bit brighter as well. F9 is a tad more comfortable in the long run, having a better package, and having detachable cables, along with a 2.5mm Balanced cable included in the package.

FiiO F9 vs Kinera H3 - At this point, Kinera H3 is slowly being phased out for the newer H3Plus, but H3's comparison with F9 might be quite interesting to quite a few readers. Starting with the bottom end, Kinera H3 has a tighter bass, a more recessed midrange, and a considerably more enhanced top end. The package is quite good for both IEMs, H3 also having detachable cables. H3 has 2-Pin connectors, thing which we wished for to be included in more IEMs, the MMCX connectors on F9 being still extremely good. In the long run, H3 is much brighter, but that brightness might also lead to more revealing abilities. F9 sounds more balanced, more even and smoother in direct comparison.

Recommended Pairings

FiiO F9 + iDSD Nano BL - One of the best pairings out there, as iDSD Nano BL is as portable as F9 is, making any Smartphone or Tablet a truly enjoyable audiophile experience. The depth of F9's soundstage is amazing with this pairing, along with the definition of each musical note, and with the general detail and resolution of F9. iDSD BL has more than enough power to properly drive F9, and it has proven to be one of the best pairings they can get.

FiiO F9 + X7mkii - X7mkii is one of my favorite flagship DAPs, also made by FiiO. Although not exactly in the entry-level price area, X7mkii gives F9 a vivid, open and dynamic sound, with excellent soundstage width and depth, all while giving them all the sparkle they need through their sound. Being quite portable, the pairing is very nice to take on a trip, X7mkii being able to drive F9 even at pretty low volumes. X7mkii's instrument separation are top notch, along with the general life and emotion they place in F9.

FiiO F9 + HIFIMAN MEGAMINI - HIFIMAN MEGAMINI is yet another excellent DAP which has proven itself through time, like most of HIFIMAN's devices, driving F9 with excellent authority and giving them a very wide and powerful sound. There is a slight trace of hiss at times, but the whole Megamini + F9 package is well worth its asking price, considering how nice both items are. Megamini tends to make F9 even wider than they are in general, giving them a slightly more forward sound, absolutely welcome for Metal and more aggressive music.

FiiO F9 + Shanling M2s - Shanling M2s is another well-priced DAP, this time focusing on features, having APT-X, and other bells and whistles, rather than sound alone. It can drive F9 quite well, giving them a slightly thicker sound, with a slightly smoother top end and giving them more depth to the sound. The focus of this pairing is its potential and wide array of usage scenarios, making F9 quite a lovely solution for your music needs.

FiiO F9 + HIDIZS AP200 - AP200 is a great source to drive F9, giving them a vibrant and vivid sound, with a wide soundstage and a fairly good instrument separation, along with excellent timing and impact to their sound.

FiiO F9 + Opus #3 - Opus #3 is one of the higher end sources one might use with F9, and it helps them gain ground when it comes to the air they have to breathe and to the general impact and vividness of their sound. Instrument separation and reveal abilities are also quite enhanced by Opus #3.

FiiO F9 + FiiO X5-3 - FiiO X5-3 is a great source for F9, and actually recommended with them as it tends to smooth out their top end a bit, giving them a slightly more relaxed and even presentation.

Value and Conclusion

FiiO F9 is priced very fairly, at around 100 USD, being one of the most accessible IEMs with a good quality to their sound and with an excellent build quality. They come packaged in one of FiiO's amazingly complete and comprehensive packages, and they come with a lot of extras, like two cables, one from which is balanced, and with a wide selection of tips.

The carrying case also adds a good value to the whole package, making F9 a complete package for outdoors usage.

At the end of the day, if somebody is searching for a balanced, to slightly V-Shaped, with a little sparkle in the top signature, FiiO F9 is one of the most comfortable options out there, with excellent ergonomics and build quality, being one of the IEMs I can recommend the most.

If there is any downside I should mention to readers interested in them, the 100$ IEM market is very crowded, with a lot of excellent offerings, which we will be reviewing in the future, and even FiiO F9's bigger brother, F9Pro, might be quite the excellent option in the long run, but as things stand, F9 is one of the best equipped, best priced IEMs with excellent ergonomics, and easily accessible IEMs from a reputable company!

The design and sound are surely worth their 100$ asking price, and if you're looking for an amazing experience at this price point, F9 should totally be in your shopping list!

I hope my review is helpful to you!

Stay safe and remember to always have fun while listening to music!

Link to the review on Audiophile-Heaven:

Link to the official Thread on Head-Fi:

Link to the writer’s head-fi page:

Audiophile Heaven:

Audiophile Heaven on Facebook:
Pros: Great packaging, material quality, price and performance, comfort, sound quality
Cons: Treble peak, sound type is nor for everyone.
Before start to review, I would like to share technical aspect and package details.


  • Headphone type: over-the-ear
  • Frequency response: 15Hz-40kHz
  • Drive type: 1 dynamic + 2 balanced armature drivers
  • Impedance: 28Ω
  • Sensitivity: 106dB/mW
  • Maximum Input Power: 100mW
  • Plug: 3.5mm straight gold-plated stereo jack/ 2.5mm TRRS straight gold0plated stereo jack
  • Cord length: 120cm
  • Single Earbud Weight: 3.76g
  • Detachable cable design: Yes (standard MMCX connector)


· Fiio F9

· 3.5mm single-ended cable with in-line controls

2.5mm balanced cable

· 6 pairs of Silicone ear tips

· Carrying case


Design & Isolation :

When I get the F9, I really liked the design and quality. The workmanship on the body is pretty solid and feels very good. The comfort is decent. The body of the F9 is quite small. It’s kind of Westone-like body and that is very comfortable in design. When you wear it, you do not feel any pressure or pain in the ear. I really liked the package and contents. There are 6 set of tips and it has Pelican style like case solid black case.

F9 comes with silicone tips and that’s provide a good isolation. I think that it has provided sufficient isolation to the outdoors.

Also, it has 1 SE cable and 1 balanced cable. Fiio done a really great job.

The F9 comes with a replaceable MMCX socket and that feels quite rigid and solid.

Sound Type:

If you look at the sound character; F9’s slightly V shaped and mids positioned further backwards. General presentation is energetic and hot treble with upper mid boost. Bass is prominent and tight.


One of the biggest improvements in hybrid design is that the bass is usually noticeable. At F9, it is not a dominant when viewed from the general character. Sub-bass are not very deep, but the overall presentation is sufficient. The bass is tight and good slam. The bass are not hitting from a wide area, it’s hitting more central. As I said before, the amount of bass is not much powerful but you can hear it when it calls.

Quantity of the bass is average. When I compare with my AAW A3H Pro V2, bass is two steps behind. But the F9 tighter and faster. The A3H Pro V2 hitting a much wider range, much deeper and more resolving but A3H PRO 2 slower than F9 and it feels more uncontrolled. F9 is better on sharp and quick passages.


Mids positioned one step backwards to the top and bottom frequencies. The presentation is not in your face. There is a quite distance. The instruments are accompanied by vocals in the middle. Space between instruments pretty good. Clarity and detail level is in this price range quite impressive. Mostly, I listened with my Opus #1 balanced output and every single detail came up clearly. I liked the timbre of stringed instruments. Male and female vocals are above average in terms of transparency.

The overall character of the lower mids a little bit thin. If you love mild, bold mid presentation, F9 is not for you. Also, upper mids a little energetic and sparkling can be harsh a bit in bad recordings.


Trebles are slightly bright, energetic and hot.

When I first removed it from to the box, the treble tones came up a little bit harsh. Then I decided to burn-in at least 100 hours. Now, treble is nicely tamed. Cymbals are audible and relatively well separated. Before burn-in, fast passages it caused complications, but after a burn-in it showed seriously relief. There is still a bit of aggression in bad record, but I have not come across a sibilance yet. In terms of resolution is pretty good. But I would recommend to use with warm source (Dap/Dac-Amp)


The soundstage of the F9 is neither very wide nor too narrow. The instruments are doesn’t overlap. Soundstage quite wide enough to make happy many people, and average in depth. The amount of distance between each instrument better than everything I have heard in this price range.


When I consider the price of the F9, package contents, quality of the material, the sense of durability it gives, sound signature and comfort I can easily recommend. I find it to have a pretty great value. Fiio getting better and better.
Pros: Pronounced & clean bass
Super clear mids
Beautiful non sibilant highs
Plenty eartip options
5N OCC Silver plated 2.5mm balanced cable
Cons: MMCX connectors a little stiff
Could have provided a better quality single ended cable
Ok, here goes my first impressions on the F9 Pro. Please note that I only listened to the earlier F9 for a brief time and found that to be a little sibilant and a tad too bright for me.

Build quality of the F9 Pro is stellar and the new titanium color which is exclusive to the Pro is nice. The 3.5mm and 2.5mm cables are the same as the previous ones but the Pro comes with 6 additional pairs of tips, so in total there are 9 pairs of silicon tips and 3 pairs of foam tips. To recap, you get 3 pairs of foam tips, 3 pairs of wide bore tips, 3 pairs of medium bore tips and 3 pairs of narrow bore tips. You also get a new carry case in addition to the hard case as per my pics above.

Sound quality out of the box is very nice. I don’t hear the unwanted brightness i mentioned about in the earlier F9 and the treble seems much smoother and easier on the ears. I tried switching the tips between the large, medium and narrow bore tips and for my listening preference, the narrow bore tips gave me a well rounded sound reproduction and the snuggest fit in my ears. The narrow bore tips also increased the bass presence a little but didn’t effect the mids and highs significantly. The sound signature is very pleasant and I found that i hear much more detail than any other IEM i have tried including the TFZ Exclusive 5 which i own as well. Staging was brilliant and much wider than the TFZ. Separation was very good and even on rock songs, it sounded a little mushy on the TFZ but sounds fantastic on the F9 Pro.

I’m not a professional audiophiler but i know good sound when i hear it and to sum it up, the Fiio F9 Pro is the best IEM i have ever set my ears upon. It’s fun to listen to, doesnt favour any frequency, has good bass when needed and sub bass is very present and very evident in songs that have the extensions well laid out. Mids are pronounced and super clear, and the highs are just beautiful, Not sibilant and nowhere near the dark sounding TFZ Exclusive 5. The Fiio F9 Pro is not the brightest sounding IEM, nether is it dark sounding. To me, it pushes all the right buttons and would satisfy the majority of listeners. It’s a very balanced sounding IEM.
I used the Fiio X3iii (balanced output) and an iPhone 6s (single ended output) as the music sources. The balanced connection from the X3iii produced much better separation and a tad more clarity to the already stellar sound signature of the F9 Pro.

I love the F9 Pro and am sure you would too.!


Pros: Amazing value for money
Punchy bass
Satisfying mids and highs
Enclosure made of aluminium
A lot of accessories included
Cons: Did not me as well as Shure SEXX5 series
Not as much external noise isolation with the included foam ear-tips as Shure SEXX5 series
Enclosure size is larger than Shure SE535 - F9-Pro stick out of my ears more

Amazing value for money. If F9-Pro is your first IEM, you will not be dissapointed.
Punchy bass, satisfying mids and highs.
Great job FiiO!

Long version of short-term review

I would not describe myself as audiophile. I just like listenning to music and value precission.
The review below is based on my personal feelings which might not be similar to yours.

My background
I started with Shure SE215 a couple of years back. Then I switched to Shure SE535 and was using those for the last year.
My audio source for a long time has been Spotify (320kbps) on iPhone + some kind of Bluetooth receiver. For the last couple months it has been the FiiO BTR1. The combo iPhone7 + BTR1 + Shure SE535 has worked quite nice up until now.
For the audio cables I have been using the stock Shure EAC64BK cable, FiiO RC-MMCX1s and SAEC SHC-100FS (PCOCC-A type conductor) interchangebly.
Ear-tips for the IEMs for me always have been memory foam tips (for the isolation and comfort). Also tested the F9-Pro with the included foam tips.
Music ranges from bass intesive Dubstep/Deep-House/EDM/Techno to Classic-Rock/Instrumental/Symphony/Piano/Chill.

Audio quality
Oh boy, the bass on the F9-Pro.. Compared to Shure SE535 it is way puncher, deeper and more pronounced. Even compared to Shure SE215, the F9-Pro wins in the bass department. Very nice. Now the bass on my Shure SE535 feels very flat. Even my girlfriend, who listenes on Shure SE215 every day, said that F9-Pro provide more bass :)
Now the mids and the highs. Well, here I have mixed feelings. In this area F9-Pro feels way nicer than Shure SE215, but not as nice as Shure SE535. The Shure SE535 feels brighter, more soundstage, more details. The F9-Pro does not feel as detailed as Shure SE535, but also not as muddy as Shure SE215. I would say it is a mix of both. Maybe the bass in the F9-Pro overpowers the other frequencies a little. I might need to spend a little more time with the F9-Pro, maybe I am just surprised and astonished with the bass they provide :) And have in mind that the price of Shure SE535 is almost 4 times than of F9-Pro - so it not a completely fair comparison.
And no hissing on the BTR1 - yay!
And mind you that Shure SE535 sensitivity sits at 119dB/mW and F9-Pro at 106dB/mW.
p.s. I mostly use this track to test the sound signature of earphones: alt-j - Breezeblocks. Try it yourself and give some feedback.

I am strong user of foam ear-tips. I like the isolation and comfort they provide. The included foam ear-tips with the F9-Pro are adequate. They do not provide as much isolation as Shure SEXX5 series. And they do not go as deep as Shure foam ear-tips. And it is quite obvious when taking out the IEMs out of the ears: F9-Pro go out way easier than Shure SE535.
The body of F9-Pro is surprisingly large (relatively speaking), I honestly thought F9-Pro would be smaller than Shure SE535, but it turned out quite opposite. And the F9-Pro, at least after couple hours of usage, does not feel as comfortable as Shure SE535. Granted, I have been accustomed to Shure SEXX5 series for a couple of years now, it is not a fair judgement now. But the F9-Pro do stick out of my ears more. And with F9-Pro I discovered that my left ear canal form is different form my right one. Because F9-Pro fit a little differently in both ears. I did not notice that before with my Shures. Interesting discovery.
Sometimes I like to sleep with the IEMs and I feel this will be more difficult with F9-Pro because they stick out more than Shure SE535.
But then I noticed that F9-Pro feel cold when putting them into ears. And I thought, could the housing be made of metal, and of course - I read through the description and the outer shell is made of aluminum. Somoehow missed that the first times I read the descriptions. Impressive to say the least and that feels that F9-Pro will last way more and be more resistant to wear-and-tear of every day life. I am always very afraid that my Shure SE535 will be damaged somehow and break.

Impressed on how much stuff FiiO provided with the F9-Pro. Nice and professional packaging - unboxing experience is very nice. Two cables - unbalanced and balanced - very impressed with the twisted-balanced cable - it's a shame I cannot use that. It would be nice to get the same quality cable for the unbalanced version (what do you say FiiO?). The amount of ear-tips is quite astonishing also. And two boxes for carrying - amazing. Well done FiiO!

All-in-all I am quite impressed with the F9-Pro. For the price you get quite a lot. I really feel this product defines a new market segment that the other manufactures will somehow have to match. The sound reproduction, the quality of the manufacturing, the included accessories (two cables, two boxes and boatload of ear-tips) - all that makes for an unbeatable user experience. You will not be dissapointed!

p.s. I will add some photos later of physical size comparison between Shure SE535 and F9-Pro.
Pros: Build quality, fit, isolation, detailed and engaging sound
Cons: No MMCX cable feature on the SE version

f9 (4).JPG

Fiio Website

F9 Series

  • Driver Type: Dynamic (9.2mm) & Dual Balanced Armature
  • Frequency response: 15Hz ~ 40kHz
  • Sensitivity: 106dB/mW
  • Impedance: 28Ω
  • Plug: 3.5mm L-shaped gold-plated stereo jack (CTIA standard)
  • Cord length: 1.2m
  • Weight: 3.76g

Price (MSRP): U$D 99

f9 (2).JPG

  • 6 pairs of single flange silicone eartips in 3 sizes (S/M/L), in two styles
  • Carrying case
f9 (3).JPG


The F9 is the first hybrid from Fiio and has a strict over-ear fit design with a very solid build quality, smooth finish and nice looks as well. The material used for the shells is all metal, lightweight and smooth to the skin. The pieces look very well assembled and the form factor is still compact enough. The so ergonomic oval shape is highly comfortable and with the not too large nozzle the earpieces sit fixed on the ears. The nozzle has a metal filter on it.

On this simpler edition, the SE has exchanged the detachable MMCX cable feature for a fixed option. However, the cable connection to the earpieces is very solid, and the cable uses long earguides without a memory wire, but still soft and easy to wear. The cable itself consists of 4 wires softly twisted from the plug to the shells. The plug is quite sturdy too, and while the cable slider is missing, the F9SE still features the cable wrap originally presented in the Dunu early IEMs.

With the over-ear design and rather sealed and ergonomic design, the isolation level is very good, regardless the eartips in use.

f9 (1).JPG


For their first own hybrid model Fiio goes for the hybrid fashion, and right from the start with the nowadays common triple configuration of one dynamic and dual armature drivers. A few years ago having a triple hybrid setup like this was quite unusual at this price point, but today is quite a standard than can be found even on low budget IEMs.

The sound itself is very well achieved. A nice tuning for a balanced, full sounding and well weighted presentation without having a too much emphasis on any frequency. Eartips’ selection is important here, and while the included ones are fine, personally I don’t find them to be the best match for the F9SE, so ended up using the SpinFit and also Sony and RHA single tips. Not a serious improvement, but did help to clean up the sound and certain peaks on the overall sound.

The signature is fairly warm, sweet and engaging. Bass quantity is definitely north of neutral, but not as obtrusive as could be expected for a hybrid setup; both the EX1 (ii) and F5 have a much stronger bass presence and higher bleed into the lower midrange. The F9SE offers better definition, layering and smoother texture, and equal sub and mid-bass balance. Speed is good, properly matching the BA counterpart as should.

Midrange is slightly forward, not too thick yet well bodied. Well articulated as for a balanced armature style, with a fairly sweet texture, speed and good separation. Plays well for any genre, from classic, pop, rock, jazz or electronic. Lower vocals are full, as well as upper vocals, though it can show a little sense of grain when reaching the lower treble. Sibilance can be present with the wider stock tips, although not an issue with other eartips.

Treble is balanced with the mids and lows. Not too bright, though a bit peaky at times (again, mostly with the stock eartips). Extension is a bit limited for could be expected on a dual BA; these are not TWFK BA sounding like the DN-1000/2000 or B2/R-50, but more similar to the LZ A3 and A4 hybrids, so easier to like, besides the treble-heads. Micro detail is very good, less forward than the GR07 Bass edition, for example, but very easy to pick.

All in all, the F9SE has a very musical presentation, with a very little laid-back touch, that makes it both detailed and enjoyable. The only drawback might be a lack of transparency and air. The stage dimensions are not too large for what can be found on hybrid sets, though it has an excellent coordination and coherence from both drivers. Dynamics are not best as single full range dynamic driver IEM can do, like the new Pinnacle P2 from MEEAudio, Vsonic GR07 or even VSD5s. It is still well rounded with good depth, and both the well designed fit and sound make it a good option for long listening session.

Unlike many triple hybrids, the F9SE impedance is more standard with a bit less sensitivity. This doesn’t make it really demanding or hard to drive, and actually shows less hiss issues and easier synergy with any portable source. Even though, the use of some extra power from a portable amplifier is very favorable with the F9SE. With the Topping NX5 (very overlooked amplifier, btw) the gain in detail, speed and resolution is quite impressive and the bass boost works as wonder, too.
How would you compare the F9 to IT01?
IT01 has more bass: more bass body and definition. stronger mid-bass emphasis but also more sub-bass presence and extension. deeper and slower decay (more natural) too.
F9 has still strong impact, but more balanced with the lower midrange, and softer sub-bass.
midrange is more forward on the F9, sweeter and better for vocals. IT01 is more v-shaped with more distant, and bit thinner mids.
lower treble is more emphasized on the F9, while IT01 more linear/balanced on the whole highs
stage is wider on the IT01
Pros: Excellent clarity, Great midrange resolution, Fantastic design and build, Comfortable, Nice accessory set
Cons: Somewhat artificial midrange and treble, Bass a bit sloppy
Introduction –

Though best known for their sources, Fiio have augmented their new devices with a line of accompanying in-ear earphones that each offer sensational value at several conservative price points. I’ve personally reviewed them all, from the humble F1 to the excellent EX1 and F5. And, through aggressive pricing and partnership with audio guru Dunu, none have failed to impress with excellent price/performance ratios combined with build quality that belies their meagre asking price. The F9 is the latest extension of Fiio’s F-series in-ears and perhaps the most technically impressive to date.

Featuring a triple hybrid driver configuration, it represents a considerable step up from the Fiio’s single dynamic driver based models. In addition, the F9 retains the removable cable of the F5 but trades its shallow semi-open form factor for a meticulously sculpted monitor style housing. Combined with a balanced cable from factory, the F9 is without a doubt, Fiio’s best built and best sounding in-ear to date but also their most expensive at $100 USD. Let’s see how the F9 competes in a price range teeming with excellence.

*Of note, Fiio have released several variants of the F9. Initial batches of the F9 had tighter MMCX connectors and smooth cable connectors where newer batches have ridged connectors and slightly looser connectors. The new batches also have a larger angle between the connectors and housing which enables cables with wider connectors to be used. Fiio have also released the F9 SE which is acoustically identical but has a fixed 3.5mm cable. A higher priced Pro model with revised armature drivers is in the works and will be released at a later date.

Disclaimer –

I would like to thank Sunny from Fiio very much for her quick communication and for providing me with the F9 for the purpose of review. All words are my own and there is no monetary incentive for a positive review. Despite receiving the earphones free of cost, I will attempt to be as objective as possible in my evaluation.

Accessories –

It’s almost unbelievable how far Fiio has come since their first iems. The F9 is very professionally packaged with attractive renders and a very fully featured accessory set. Inside the box is Fiio’s excellent pelican style hard case that contains the earpieces and 6 pairs of silicone ear tips. The tips are quite interesting, there are 3 pairs of regular tips and 3 eQ tips that enhance the bass response, similar to that employed by the Simgot EN700 Bass.

During listening, I found them to provide very noticeable tonal adjustments with the red tips offering my most preferred sound. A small box just above contains two cables, a regular 3.5mm cable with a 3-button smart remote and a very nice braided 2.5mm cable for use with a balanced source. It’s a nice inclusion that is very uncommon at this price point and the inclusion of a remote cable is thoughtful for those that intend to use the F9 with a smart device.

Design –

The F9 is a striking earphone with a beautiful rippled design and two-piece aluminium construction. They are easily among the best-constructed earphones around $100 if not the best with finish and solidity that matches earphones costing several times more. Further yet, their smooth satin finish serves to accentuate the fascinating quality of their undulating outer face, creating a stunning visual package that belies its asking price.

Fiio have also carefully considered ergonomics when designing the F9. Though not especially compact, the F9 is a far from a large in-ear, about the same size as the Shure SE215, with long but low-profile housings that make them perfect to sleep on. The earphones also generate little wind noise when outside despite their rippled design.

Through smooth sculpting and longer nozzles, the F9 achieves nice fit depth and great stability in the ear. They were perfectly comfortable for me even after extended listening, forming no hotspots. That said, due to two internal vents, the F9 doesn’t quite isolate as well as some competing models like the Rose Mini 2 and Pinnacle P2 but they still block more noise than the semi-open F5, K3 HD and EN700 bass and will be sufficient for public transport.

Up top, the F9 utilizes a removable MMCX cable. Fiio were quick to note that the MMCX connectors are much tighter than those on the F5 before and that newer batches of the F9 have a slightly larger MMCX connector angle that permits the use of 3rd Party cables (where initial units were a bit too tight). This enables users to swap the cable in the event of damage or upgrade to a superior unit in the future. That said, the stock cables are quite good, the remote cable is rubbery but serviceable while the balanced cable is genuinely compelling.

Both have well-formed pre-moulded ear guides that I vastly prefer over memory wire and the balanced cable has a nice loose braid that is exceptionally supple and soaks up microphonic noise. The cables also have an integrated strap that keeps everything organized. Otherwise, the cables are mostly well relieved, more so than the cables that came with the F5 and the connectors are tight without intermittency.

Sound –

Tonality –

The F9 is a clearly V-shaped earphone with a slight emphasis on treble over bass. That said, mid-bass is present, providing a solid foundation for the rest of the sound while mids are clear and extended but less forward. Lower treble is spiked creating a rather uneven high-frequency presentation though this can be altered via eQ and tip choice. Of note, I did prefer the red tips to the black ones, they were more balanced overall while the black tips murdered bass definition and sounded a little less natural within the mids and treble. Foams further smooth off the high-end though I personally prefer silicones during daily use for their convenience. I’m also not a fan of eQ since it can be hard to create a reliable experience among multiple sources. Thus, the F9 sits in-between the more V-shaped Kinera H3and more balanced Pinnacle P2 in terms of tuning, it is a tone that possesses enough balance for the majority of genres and one that many listeners will be familiar with.

Bass –

Low frequencies are quite typical but mostly tasteful in tonality and the F9 has certainly proven to be one of the better technical performers I’ve heard around this price. Sub-bass is slightly elevated with good but not great extension, the F9 is on the looser side though impact is firm and rumble is easily discerned. They perform on a similar level to the Simgot EN700 Bass and Magaosi K3 Pro but fail to match the class-leading Kinera H3 and TFZ King in terms of overall extension and technical ability. This is followed by a modest mid-bass hump that grants the F9 with a fuller bass note but also a little bloat, and they are immediately less nuanced that the aforementioned H3 and the K3 HD as a result. Upper bass is more reserved but still well present and the F9 avoids bass spill or warming of its lower midrange as a result.

Bass texture and definition are both good though some details get buried beneath their mid-bass bloat. They also aren’t the tightest, most agile earphone around this price, easily outpaced by the competitors like the Pinnacle P2. During faster, more complex songs such as Earth, Wind & Fire’s “Boogie Wonderland”, the F9 can get a little lost and bass notes are somewhat one-note when compared to the more linear, more balanced King and Mini 2. Even the H3, which possesses greater bass emphasis, achieves a higher level of technicality through greater bass control. The F9 is certainly not a bad performer, quite the opposite, but the quality of their bass doesn’t quite match its driving emphasis within the sound. Still, those looking for great extension and impact combined with good detailing will find a very agreeable experience with the F9.

Mids –

The first things that listeners will notice is the F9’s outstanding midrange clarity that grants vocals, both male and female, with a certain glossiness and extension. As a result, the F9 does not sound particularly natural and vocals do come off as a bit thin and oddly voiced but I can definitely see a lot of listeners enjoying this presentation; the F9 really flatters pop, acoustic and well compensates for the more veiled mastering of older albums. In terms of tone, the F9 is a brighter earphone with slightly recessed male vocals preceding rising emphasis into the upper mids and treble. However, male vocals still avoid a scooped sound and the F9’s midrange sounds pretty balanced in the majority of situations. As a result, the midrange of the F9 sounds more even than the H3 with similar overall linearity to the Pinnacle P2. My main complaint stems from a sizeable lower treble/upper midrange peak that can overly emphasise sibilance and saps smoothness from the midrange. Vocals often sound a little strident and instruments can come off as raspy.

However, from a technical standpoint, the F9 does impress, augmenting its clarity with excellent resolution that is among the highest I’ve heard around this price and even above it. The F9’s enhanced treble though not natural or refined, does notably aid space and extension of elements. Female vocals and strings, in particular, sound airy, delicate and separated making the F9 a great choice for acoustic. Courtney Barnett’s “Small Poppies” was flattered with exquisitely clear vocals, crisp guitars and great separation between elements. Furthermore, layering is very defined and the F9 is still surprisingly natural given its style of tuning. So those coming from warmer earphones like the Simgot En700 Bass might require some acclimatization to the F9’s thinner, clearer tones, however, they do reward with a mostly balanced and very technical listen.

Highs –

The F9 has been getting a few criticisms regarding its aggressive, spiked treble response. And though everyone has differing levels tolerances, to my ears, highs aren’t harsh but they do get a bit overzealous. And this style of tuning certainly isn’t something we haven’t seen before, almost all Chi-Fi iems around this price have a bumpy treble response that either serves to heighten detail presentation or create the impression of air within a less extended response. It’s called compensation because on a superficial level, these iems sound similar to more technical models but lack the actual underlying technicality to present these elements in a natural fashion. The F9, thankfully doesn’t have to compensate for too much, its high-frequency response is nuanced, detailed and clear. Treble extension is very good but not absolute, the very highest details are still a little truncated though less so than competing models. Otherwise, middle treble is a little lifted while higher notes are a little smoother and more restrained to avoid outright harshness and fatigue.

And breaking that down a bit more reveals impressive underlying technicality. As aforementioned, lower treble is aggressive and notably accentuated though actual detail retrieval is good, roughly similar to models like the Pinnacle P2 and just below the H3 and K3 HD. That said, the F9 is very aggressive in its presentation, bringing every little nuance to the fore though without the forwardness of the King. This is augmented by very commendable resolution that grants treble elements with great clarity and immediacy. That said, texturing does suffer due to their thinner, spiked presentation that lacks the linearity to portray accurate instrument timbre. As a result, the F9 is a detailed, hyper clear earphone with nice air but also a somewhat artificial tone to instruments and the extent that this bothers the listeners will depend on preference and music taste.

Soundstage, Imaging and Separation –

As a result of their airier, hyper-crisp treble response, the F9 produces a very nice soundstage presentation that is among the best I’ve heard around this price, especially through a balanced connection. Width is great, extending to the periphery of the head and depth is notably more immersive than competing models. This is especially noticeable with vocals that extend exceptionally well on the F9. Imaging is good but not outstanding, directional cues are accurate and clear and instruments are easily located. Centre image to vocals is a bit hazy and diffuse and most elements tend to become pushed to the side of the soundstage. Separation is excellent due to their defined transition between lows, mids and highs in addition to enhanced clarity and resolution.

Drivability –

The F9 is one of the easier to drive earphones I’ve tested with a 28ohm impedance and 106dB sensitivity. Users shouldn’t want for more volume even from smartphones or portable MP3 players and those with any sort of dedicated DAP will have no trouble driving the F9 to potential. Due to its cool resolving tone, the F9 finds particularly strong synergy with warmer, more laid-back sources. I found the Chord Mojo and Shozy Alien+ both to provide extra smoothness and refinement to the F9’s excited sound in addition to a little extra body all without sacrificing detailing. My HTC 10 also provided a fine pairing with plenty of volume and the F9 was not overly affected by output impedance in my testing. Of course, the F9 can also take advantage of a balanced output, from my X7 II w/AM3 module, I noticed slightly more separation and greater bass weight and control as opposed to the regular 3.5mm output. It’s also possible that the cable itself is contributing as on the F5 in addition to greater driving power from these outputs.

Comparisons –

Rose Mini 2 ($100): The Rose and F9 couldn’t diverge much more in their tonality. Where the F9 is clear and engaging, the Mini 2 is neutral with a tinge of warmth. Bass extension easily goes to the F9 and the Fiio possesses notably more slam and impact, though the Mini 2 is much faster and considerably more defined if more reserved in quantity. Mids are far more linear on the Mini 2 and though the Rose lacks the outright clarity and resolution of the F9, the Mini 2 is a lot more natural and far more refined.

Mids are better balanced with the rest of the sound on the Mini 2, it is also more bodied and transparent with more accurate timbre. Highs are far more aggressive on the F9 and though the Mini 2 is just as detailed, it is more on the laid-back side in terms of presentation. The Mini 2 isn’t spiked like the F9 and resolves greater texture and micro-detail as a result. However, it can sound a little sedate and air is not its forte. The F9 also has a large advantage when it comes to soundstaging, though the Rose images a little better, the Fiio has greater space in all axis and notably higher separation.

Simgot EN700 Bass ($100): The Simgot is a delightfully warm, natural earphone that contrasts to the V-shaped competition. It is bassier than the F9 with a bigger mid-bass hump though it is less extended and defined. That said, the Simgot is nicely articulate and bass/midrange transition is smoother so lower mids are more natural as a result. The F9 is clearer but also much thinner, it sounds thoroughly artificial compared to the EN700 Bass if more resolving. Upper mids are clear and clean on the Simgot but even clearer on the F9.

The Simgot clearly lacks the technical ability of the Fiio, the layering and resolution isn’t quite there nor is the detailing, but they make up for it with tonal excellence, they are so much smoother and more refined. Treble is more laid-back on the EN700 Bass with average extension and air. The F9 is a lot more aggressive and extended and raw detail retrieval is appreciably better. On the flipside, the EN700 Bass is much smoother and more textured while retaining some crispness. The En700 Bass has a very nice soundstage on account of its almost semi-open design. The Fiio has less width but a little more depth and both image similarly well. Separation is a little better on the F9 due to its greater extension and more dynamic tuning.

TFZ King ($100): The King and F9 make for interesting comparison since both earphones pursue absolute technicality over tonal refinement yet through differing approach. The King is a bright, forward sounding earphone while the F9 balances its prominent high-end with greater bass quantity. Both are similarly well extended but the King’s low-end is more defined and agile. That said, low-end details can become overshadowed by higher elements, something the Fiio doesn’t suffer from. Mids on the King are considerably more forward in the mix and find a better balance between clarity and smoothness.

The F9 pushes clarity a step further but also sounds a little harsher and less refined. As such, though both have excellent resolution and layering, the King is a bit more linear with better background detail retrieval. The King has a similarly spiked high-end though its emphasis lies in the middle rather than lower treble. As a result, it is airier but splashier with a similar lack of body and the F9 is more separated and detailed without the overbearing brightness of the TFZ. The F9 has a larger stage, especially depth in addition to appreciably better separation though imaging is more accurate on the King.

Kinera H3 ($100): The H3 is the more engaging counterpart to the F9 and P2 with a notably more visceral bass response combined with a similarly clear midrange and high-end. Sub-bass extension is better on the H3 and bass is greater in emphasis with a more deep bass over mid-bass focus. As such, though the H3 is bassier, it is more defined, controlled and articulate. Mids are more recessed on the H3, lower mids sound a bit scooped compared to competing models though clarity and body are both excellent. And though the F9 is more balanced throughout, the H3 is almost as clear but warmer and more bodied. The H3 actually matches the F9 on resolution but it is also slightly more natural with greater definition of layering.

Highs are actually brighter on the H3 but also more resolving and separated which acts to counteract some of its peakiness. Both are very aggressive yet well-detailed earphones, the H3 a little more so since its treble emphasis extends a little further up. As such, the H3 doesn’t overshadow as many higher details and instruments sound a little more linear if pushed forward in the mix. The F9 once again has the larger soundstage, especially depth which provides vocals with an immersive character. Separation is better on the H3 while imaging is similar on both.

Meeaudio Pinnacle P2 ($100): The P2 pursues almost identical tuning to the F9 but with better balance throughout, this is probably the most pertinent comparison of the bunch. Bass is similar on both, the F9 has a hair more extension and greater emphasis throughout though the tuning is similar. The P2 is considerably faster but also tighter and more defined, it has a touch more upper-bass quantity that grants mids with a slightly warm tone as opposed to the thinner, cooler F9. Both possess a clarity driven midrange though the P2 is smoother and more refined, less affected by the sibilance and peakiness of the F9. The P2 is also slightly more balanced, though still lightly v-shaped overall.

Resolution is slightly higher on the F9 though the P2 is more detailed due to its greater body and more natural presentation. Highs are also similar, lower treble is spiked on both, the P2 to a lesser extent. As a result, the P2 has less aggression but also sounds smoother and more detailed, cymbals are more textured and notes are less raspy in general, female vocals are also less strident. The F9’s soundstage has greater depth and a little more width than the P2 though it is the less coherent sounding earphone with inferior imaging. Both separate very well, the P2 more so since it is less peaky and more balanced.

Verdict –

Fiio’s lower F- series earphones were sensational. They were priced competitively, built better than competitors and were tonally brilliant to top it off. However, unlike these models, the F9 sits within a price range overflowing with competition, some that strive for great balance and some greater engagement. There is no doubt in my mind that the F9 offers a great sense of value but what a lot of listeners and critics fail to acknowledge is that $100 buys you a lot of earphone these days and this is demonstrated by models like the Rose Mini 2, Kinera H3 and Meeaudio Pinnacle P2. As a result of this fierce competition, I would argue that even these mostly affordable in-ears can no longer be fully excused for treble peaks, unnatural voicing and uneven bass tuning, at least, not to the extent shown here.

Because, like the K3 Pro, the F9’s sculpted tones come with several inherent caveats that some competing models don’t suffer from. The Meeaudio Pinnacle P2 serves as a great example, that earphone fits better, isolates more and pulls off the same kind of sound but with greater balance and refinement. However, with the right material, the F9 sings like few others around this price with class-leading resolution and clarity within a well-featured and beautifully shaped housing. And at the end of the day, tonality is a preference and though the F9 doesn’t fit mine, those that prefer a clear, resolving V-shaped sound and don’t mind the treble, will find a delightfully technical listen. This technicality also makes them an excellent choice for those who like to experiment with eQ, they are indeed very response with great potential lying beneath wonky tuning.

Verdict – 7.75/10, The F9 is not an outstanding earphone but one that firmly deserves its asking price. For a reasonable price, Fiio provide buyers with an excellent housing, balanced capability and a resolving V-shaped sound. However, while technically impressive, that sound lacks the tonal refinement to stand above the rest.

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Pros: Excellent price/performance ratio.
Good transient response.
Good channel matching & instrument separation.
Easy to drive.
Detachable cable.
Cons: Stock ear tips don't do these any favors.
Treble peak can be fatiguing if not eq'd.
3.5 mm cable easily tangled, no right angle plug, limited strain relief.
I've had mine since 2017-08-31, and I'll pony up my subjective ratings. They're not based on instrumented measurement, and the ratings are normalized for price range; at this price, the F9 pins the needle for me. I'm including comparative lower/upper ranges of ratings based on other IEMs I've owned. The comparative ratings take into account their "historical" status, so I'm treating them as equal in price range. You can witness my IEM journey in those selections.

I've had the F9s long enough that burn-in shouldn't be a factor, as I've been using them a few hours every day. I re-listened with the stock tips this week.

I settled on Comply Ts-200 foam tips, and am applying equalization using the EQu app on my iPhone 6s. I tend to favor a balanced frequency response, and have somewhat limited hearing in the upper range, so YMMV.

IEMs for comparison: Shure e2c (Single Dynamic), JAYS d-JAYS (Single BA), Phiaton PS 200 (Double BA), Sony XBA-30ip (Triple BA), OM Audio Inearpeace (Hybrid single BA).

Subjective frequency response (stock tips, no eq.): 8/10. The treble peak with the gray tips was very fatiguing, and bass was a bit too booming for me with the red tips. In both cases, I was wanting for a little more forward midrange.

Subjective frequency response (Comply Ts-200, no eq.): 9/10. The foam tips helped smooth things out considerably. It was quite noticeable. The treble peak is still making itself apparent, though fatigue didn't seem to be an issue anymore. I'd like just a touch more low bass and midrange. Comply Tsx-200 may help tame the treble peak a bit more, due to the extra wax filter.

Subjective frequency response (Comply Ts-200, EQu): 10/10. A little tweaking (+2 dB @ 20 Hz, 600 Hz, -2 dB @ 2 KHz, -3 dB @ 7 KHz) really brings these around for me. They compare favorably to my Sony XBA-30ip, except in sub-bass extension (the Sony's are triple BA, were almost twice the price, and are more difficult to drive). JAYS d-JAYS (6/10), Sony XBA-30ip (10/10).

Driveability/impedance: 10/10. 28 Ohms. Bass extension did not noticeably improve when I switched from my iPhone 6s to my Schiit Magni, and clipping was not an issue when I eq'd with my iPhone. OM Audio Inearpeace (10/10), Sony XBA-30ip (7/10).

Transient response (Comply Ts-200, EQu): 10/10. The dynamic driver is quite good in this regard; I'd love to see waterfall plots of these. Shure e2c (6/10), Sony XBA-30ip (9/10).

Instrument separation (Comply Ts-200, EQu): 10/10. Note that bringing up the midrange helped a lot, in this regard. Shure e2c (6/10), Sony XBA-30ip (10/10).

Soundstage (Comply Ts-200, EQu): 8/10. Equally wide and deep. I perceive that channel-matching is very good; when I was tweaking eq, I didn't sense any left-right bias. Shure e2c (7/10), Phiaton PS 200 (10/10).

Isolation (Comply Ts-200): 8/10. My main concern is the isolation of wind noise when I'm on my bicycle. These are partially vented, and the outside of the enclosure is scalloped. Basis: OM Audio Inearpeace (3/10), Shure e2c (9/10).

Comfort (Comply Ts-200): 9/10. Fit and retention are pretty good, and I'm able to lay on my side with these. Nozzle diameter isn't an issue. OM Audio Inearpeace (6/10), JAYS d-JAYS (10/10).

Cable (3.5 mm, unbalanced): 6/10. The fact that it's detachable keeps this from lowering the overall rating. There is cause for concern with the strain reliefs; they aren't graduated, and the 3.5 mm plug is not right angle. The grippy jacket and fixed ear hooks are very easily tangled. I'd prefer a more slippery jacket material, a slider, and no ear hooks. I haven't tested the mic yet, but the control switch works well, though the cylindrical shape makes it harder to locate the buttons on the fly. Aluminum materials tell me that FiiO cares about quality, but I need to be careful that they don't scratch my phone if I put them in my pocket. I'm keeping my eye out for a suitable MMCX cable replacement, with better strain reliefs and a slider. Phiaton PS 200 (1/10), Sony XBA-30ip (10/10).

Cable (2.5 mm, balanced): Not evaluated.

This may be a premature statement, but I think these are a game-changer, in terms of price/performance ratio. I'll be interested to hear the differences in the upcoming Pro version. Reference hybrid 2BA for the rest of us!

Update (2018-01-27): The stock unbalanced cable is beginning to cut out audio in both channels. I think it's due to repetitive stress damage of the sheath at the 3.5 mm plug strain relief. Full disclosure: I use these while running and cycling, often with my iPhone 6s in my pocket. This isn't the first cable of mine to fail at that location. I will say that I have not seen this type of failure in the same conditions with right-angle plugs.

I ordered some 3rd-party replacement cable(s) on AliExpress (couldn't find any I liked from domestic sources) on 2018-01-11; they just showed up at my door in San Jose today.

The comments below pertain to the 3rd-party cable, in comparison to the FiiO unbalanced cable that comes with the F9.


This cable was 2 for $13.15, delivered. It works well; media controls (play/pause, volume up/down) are compatible with my iPhone, and it's much easier to operate the buttons. The FiiO controls are in a cylindrical enclosure, which makes orienting to the switches very difficult.

The cable jacket is not too grippy for use during exercise, and is much less prone to tangling, which is also helped by the less aggressive curvature of the ear hooks. The MMCX connectors, while feeling like a sturdy connection, are easier to rotate and insert/remove. So far, so good. We'll see how long they last.
Pros: Sound quality, build quality, balance, fit, comfort, value, balanced and SE cables
Cons: 7 kHz peak is overdone

Picture are default 1200 x 800 resolution - click to view larger images.

FiiO has been on a bit of a roll lately – introducing new product lines, and updating old ones. They also branched out into earphones and ear-buds – starting with the F1, EX1, and more recently the F3 and F5. They've proven to be very good – especially at the more budget end of the scale. I remember suggesting to FiiO a while ago that I'd love to see what they could do if they were to put their mind to a truly ergonomic IEM – similar to other offerings from Shure or Westone. They must have been of a similar mind-set, because we now have newly released their F9 – a triple driver hybrid at an unbelievable USD 99.

So lets take it for a little spin, and see what they've come up with


By now, most Head-Fi members should know about the FiiO Electronics Company. If you don’t, here’s a very short summary.

FiiO was first founded in 2007. Their first offerings were some extremely low cost portable amplifiers – which were sometimes critiqued by some seasoned Head-Fiers as being low budget “toys”. But FiiO has spent a lot of time with the community here, and continued to listen to their potential buyers, adopt our ideas, and grow their product range. They debuted their first DAP (the X3) in 2013, and despite some early hiccups with developing the UI, have worked with their customer base to continually develop the firmware for a better user experience. The X3 was followed by the X5, X1, X7 and most of these DAPs are now into their 2nd or even 3rd generations.

They've also developed new cables, desktop and portable amplifiers, DACs, ear-buds and earphones. FiiO’s products have followed a very simple formula since 2007 – affordable, stylish, well built, functional, measuring well, and most importantly sounding good.


The FiiO F9 IEM that I’m reviewing today was provided to me gratis as a review sample. Although I have made it clear to FiiO on many occasions that I still regard any product they send me as their sole property and available for return any time at their request, they have told me that the product is mine to do with as I see fit. So I thank them for the ability to continue use of the FiiO F9 for follow up comparisons. I do not make any financial gain from this review – it is has been written simply as my way of providing feedback both to the Head-Fi community and also FiiO themselves.

I have now had the FiiO F9 IEM for around 4 weeks. The retail price at time of review is ~ USD 99.

PREAMBLE - 'ABOUT ME'. (or a base-line for interpreting my thoughts and bias)

I'm a 50 year old music lover. I don't say audiophile – I just love my music. Over the last couple of years, I have slowly changed from cheaper listening set-ups to my current set-up. I vary my listening from portables (mostly now from the FiiO X5iii, X7ii and iPhone SE) to my desk-top's set-up (PC > USB > iFi iDSD). My main full sized headphones at the time of writing are the Sennheiser HD800S, Sennheiser HD600 & HD630VB, and AKG K553. Most of my portable listening is done with IEMs, and it has mainly been with my own personally owned IEMs - the Jays q-Jays, Alclair Curve2 and Adel U6. A full list of the gear I have owned (past and present is listed in my Head-Fi profile).

I have very eclectic music tastes listening to a variety from classical/opera and jazz, to grunge and general rock. I listen to a lot of blues, jazz, folk music, classic rock, indie and alternative rock. I am particularly fond of female vocals. I generally tend toward cans that are relatively neutral/balanced, but I do have a fondness for clarity, and suspect I might have slight ‘treble-head’ preferences. I am not overly treble sensitive, and in the past have really enjoyed headphones like the K701, SR325i, and of course the T1 and DT880. I have a specific sensitivity to the 2-3 kHz frequency area (most humans do) but my sensitivity is particularly strong, and I tend to like a relatively flat mid-range with slight elevation in the upper-mids around this area.

I have extensively tested myself (ABX) and I find aac256 or higher to be completely transparent. I do use exclusively red-book 16/44.1 if space is not an issue. All of my music is legally purchased (mostly CD – the rest FLAC purchased on-line). I tend to be sceptical about audiophile ‘claims’, don’t generally believe in burn-in, have never heard a difference with different cables (unless it was volume or impedance related), and would rather test myself blind on perceived differences. I am not a ‘golden eared listener’. I suffer from mild tinnitus, and at 50, my hearing is less than perfect (it only extends to around 14 kHz nowadays). My usual listening level is around 65-75 dB.

For the purposes of this review - I used the FiiO F9 straight from the headphone-out socket of many of my portables, but predominantly the X5iii, X3iii and my iPhone. I did not generally further amp them (I did test them with my E17K and A5), as IMO they do not benefit greatly from additional amplification (YMMV and it may depend on your source). In the time I have spent with the FiiO F9, I have noticed no change to the overall sonic presentation (break-in). Time spent now with the F9 would be approximately 25-30 hours.

This is a purely subjective review - my gear, my ears, and my experience. Please take it all with a grain of salt - especially if it does not match your own experience.

One last thing – I've notice of late my reviews have been getting too long, so this is my attempt at abbreviating them a little. Feedback is welcome


The FiiO F9 arrived in their usual approximately” 110mm x 165mm x 53mm retail box with a picture of the F6 on the front cover and specifications and package contents on the rear. The retail box is black with the occasional red highlight, and white easy to read text. Inside the retail outer is a black box and lid – simply adorned with the FiiO logo.

Inside you get a black glossy Pelican case and a cardboard mini box containing the cables. Inside the Pelican case is a foam cut-out with the FiiO F9 safely nestled in the provided grooves. There is also two cardboard plates which house the included tips. The tip selection includes 6 sets of silicone single flange tips. There is also a warranty card and manual.

Retail boxFull accessory packageF9, cables and carry case
The tips come as “Bass” or “EQ” options – and the “bass” ones actually seal a little bit better for me (hence the bass designation I guess). The “EQ” once don't seal for me personally so not my ideal combo.

The storage case is very similar to the Dunu Pelican type cases, has internal measurements of ~ 98mm x 58mm and approx 34mm deep. It is rigid with felt like internal padding and provides pretty good protection as well as storage. Because of it's size, its more suited to jacket pocket than pants pocket use. FiiO includes two replaceable cables (MMCX) – a 3.5mm standard stereo option (with on-cable controls) and a 2.5mm balanced option.

All in all, the accessory package is very good at this price point – especially having the two cable options.

(From FiiO's packaging / website)
ModelFiiO F9
Approx price$99 USD
TypeTriple Driver Hybrid
Driver DD1 x 9.2mm Titanium DD
Drivers BA1 x dual BA unit
Freq Range15Hz – 40kHz
Sensitivity106 dB /mW
Cable1.2m, replaceable (MMCX) x 2
Jack3.5mm gold plated straight
Weight21g with default cable
Casing materialAnodised CNC aluminium alloy


The graphs below are generated using the Vibro Veritas coupler and ARTA software. Ken Ball (ALO/Campfire) graciously provided me with measurement data which I have used to recalibrate my Veritas so that it mimics an IEC 711 measurement standard (Ken uses two separate BK ear simulators, we measured the same set of IEMs, and I built my calibration curve from shared data). I do not claim that this data is 100% accurate, but it is very consistent, and is as close as I can get to the IEC 711 standard on my budget.

I do not claim that the measurements are in any way more accurate than anyone else's, but they have been proven to be consistent and I think they should be enough to give a reasonable idea of response - especially if you've followed any of my other reviews. When measuring I always use crystal foam tips (so medium bore opening) - and the reason I use them is for very consistent seal and placement depth in the coupler. I use the same amp (E11K) for all my measurements - and output is under 1 ohm.

The graphs are provided merely as a point of discussion, and later in the review I've included comparisons to other IEMs for similar reference.

My quick sonic impression of the FiiO F9 – written well before I measured:
  • Bass is very linear but also has good extension, with a small mid-bass hump. There is audible sub bass rumble but it is in balance with the rest of the signature and does not overpower.
  • Lower mid-range is also reasonably linear, with a light recession. Both male and female vocals are well represented and sound quite natural. Upper mid-range is emphasised, and reaches a peak in the presence area. Female vocals have a a very good sense of euphony, and there is good cohesion and transition from lower to upper mid-range.
  • Lower treble extension is good but there is a strong peak around 7 kHz. Detail is extremely good but there is some definite heat at 7 kHz.
  • Overall a nicely well balanced earphone with good extension both ends, and just one troubling peak in the lower treble.
  • Channel matching is extremely good on the pair I have.


The FiiO F9 is beautifully built and seeing what FiiO can do for sub $100 really does make me question how so many other companies struggle to get ergonomic design right. The main body is CNC'd, sand blasted and then anodized for a really nice metallic finish. There is a design on the outer shells, but even that is devoid of hard edges. The entire shell is beautifully rounded and sized to perfection

The F9 measures approx 21mm across with a total height (including cable exit) of 17mm, and depth of 12mm.The nozzle is angled forward and extends approx 6mm from the main body (so relatively shallow fitting). It is 5mm in diameter with a generous lip and mesh protective cover.

External viewFront viewInternal view
On the internal face of each unit are two ventilation ports and an engraved L or R designator. The cable exit uses an MMCX connector and this is situated on top of the main body, and naturally forward. FiiO have taken the critique of their F5 on board and this time the connectors are tight – although they still do not sit entirely flush with the body.

The F9 comes with two included cables – a standard 3.5mm stereo which has in-line mic, volume and playback controls, and also 2.5mm balanced cable option. Both cables have a hard rubber / moulded plastic housing for the MMCX connector which then joins to preformed flexible ear-hooks which are extremely comfortable and keep the IEM in place brilliantly (I love this design). On the housing is either L or R markings, but the black on black is quite difficult to see. The left cable does have a raised bump though which makes things slightly easier.

Rear viewNozzle lipConnectors
The SE cable has a control unit on the right side which hangs just about equal with my jaw if worn cable down (so ideal height for the mic). The on-cable controls are designed to work with Android devices and do so brilliantly with FiiO's X1ii, X3iii, X5iii and X711 devices, allowing play/pause (one push), next track (two pushes), and previous track (three pushes). The volume control rocker also works. The microphone is crystal clear for calls (with my iPhone SE), as is the audio. I also tried the F9 with my wife's Galaxy, and everything worked as it should.

Below this (about mid-chest) is a small tubular y-split with good relief below the split, but no relief above it. Y splits tend to be a little more forgiving in terms of wear, so no real issues with this. The jack is gold plated, 4 pole (for the in-line controls) and nice and skinny for use with smart-phone cases. It is also well relieved. The balanced cable is a very soft and pliable twisted pair, and FiiO tells us it is silver plated OFC. There are the same formed ear-loops and this time a 2.5mm balanced jack.

Control unit3.5mm jack2.5mm balanced jack
Both cables have a very “Dunu like” rubber cable tie intact with the cable – the same as that used on their other IEMs and pretty much all of Dunu's releases now. This is a really simple mechanism that is unobtrusive - but means that whenever it's time to store the IEMs, the cable is always tidily looped. This remains one of the most simple, yet practical, methods of cable ties I have ever seen.


I'll start with the easy one (isolation), and we can then look at fit and comfort. Isolation will be a little dependent on tip selection, and if you get a good seal, it is slightly above average for a hybrid with a dynamic driver. It is pretty good for most situations, but as soon as things start getting too noisy (public or air transport etc), you may find yourself wanting something with a little more isolation. The F9 are designed to be worn cable up. Fit and comfort is exemplary – especially with the formed loops.

Most tips fit pretty wellAnd the F9 are superbly comfortable
I have one ear canal slightly different to the other one (my right is very slightly smaller) - so I tend to find that usually single silicon flanges don't seal overly well. This is often even more of an issue with shallow fitting IEMs. Because the F9 has a nice nozzle lip, I had no issues fitting any of my tips, and had great success with Ostry’s blue and black tuning tips, Sony Isolation tips, Spin-fits, and also Spiral Dots. I've just ended up using standard large Complys though – for a great combo of seal and comfort. And seems to dull the 7 kHz spike just a little.

The FiiO F9s sit nicely flush with my outer ear, and are extremely comfortable to lie down with. I've slept with them more nights than I can count now, and have had no discomfort on waking. The combo of the in-line controls with a FiiO DAP makes them brilliant for late night.

So how do they sound?


The following is what I hear from the FiiO F9. YMMV – and probably will – as my tastes are likely different to yours (read the preamble I gave earlier for a baseline). Most of the testing at this point (unless otherwise stated) was done with my X7ii, no EQ, and large Comply tips. I used the X7ii simply because paired they not only gave me a very transparent window to the music with low impedance, and more than enough power – but also allowed me to use the balanced option. There was no EQ engaged.

For the record – on most tracks, the volume level on the X7ii (paired with AM3a) was around 45-50/120 (on low gain) which was giving me an average SPL around 65-75 dB. Tracks used were across a variety of genres – and can be viewed in this list


  • Sub-bass – good extension, nice audible rumble, balanced with rest of spectrum and doesn't over-power.
  • Mid-bass – very slightly elevated almost like an HD600. Sounds natural and gives good impact without masking the mid-range.
  • Lower mid-range – slightly recessed compared to bass and upper treble, but not enough to make vocals distant. Male and female vocal fundamentals are really good – rich and full.
  • Upper mid-range – elevated compared to lower mid-range, and there is a very rise from 1 kHz to the first peak at ~2.5 kHz. Cohesive transition form lower to upper mids, and very good euphony for female vocals.
  • Lower treble has a nice balance throughout, but a strong peak at 7 kHz (very similar to HiFiMan's new RE800). There is great detail, but also some heat which can make it fatiguing.
  • Upper treble rolls off like most headphones from about 14 kHz onward – but enough extension to provide “air”.
Resolution / Detail / Clarity
  • Clarity overall is really good. Upper mids and lower treble have enough emphasis to give guitars bite and definition. Micro details are very evident.
  • Cymbal hits have a lot of clarity and presence but because of the 7 kHZ peak, they are also over emphasised and a touch hot or harsh. Cymbal decay sounds overdone.
Sound-stage, Imaging
  • Directional queues are good without being over emphasised. Presentation of stage is mostly just on the periphery of my head space with binaural tracks, but the violin in Tundra does sit outside (nice portrayal of width).
  • Elliptical sense of sound-staging – with slightly more lateral L/R leaning rather than depth.
  • With the applause section of “Dante's Prayer”, the FiiO F9 shows a good sense of immersion (the sound of the audience flowing around me), but there is more width than depth. “Let it Rain” is usually my next track to listen to and it gave a nice 3 dimensional feel (the way it is miked). Guitar is crisp and clear. There was a lot of sibilance with Amanda's vocals – and it should be there because its in the recording – but the F9's peak at 7 kHz is embellishing it for me.
  • Overall clarity and balance of the signature.
  • Reasonable sense of stage and imaging
  • Good cohesion with lower and upper register vocals
  • Great for both female and male vocals and with enough bass warmth to stop things being too dry or sterile.
  • Lower treble spike is just too prominent. It is the only issue with an otherwise excellent close to reference signature.

The FiiO F9 doesn’t need amplification for overall volume – and because its impedance isn't overly low, any source with an output impedance of less than 3 ohms should pair OK.

With my iPhone SE around 35-45% volume is more than enough with most tracks, and the FiiOs are generally at around 45-50/120. I tried the F9 with the E17K and A5and none of them seemed to be adding anything to my listening set-up other than some extra bulk. The A5 was really overkill, and I had to be careful to use variable line-out to get a usable volume.

This is an easy one – drop the 7 kHz spike, and you get a far better overall signature. With the X7ii, this was simply a matter of dropping the 8 kHz slider by -6dB and upping the volume a bit. This took the heat out of the overall signature and brought a lot of realism to the modified signature. I'd go as far as saying that with this EQ applied, the F9 could easily sit with monitors in the 250-300 range.

I measured these, and there was no difference with the X7ii's AM3a amplifier module apart from volume. Even the slight change in impedance wasn't enough to change the overall frequency response. I'm not a great believer in the adage that balanced makes a huge difference. Yes, if the implementation is vastly different you can sometimes notice a difference, but more often than not the changes to cross-talk are already below the audible barrier, and most modern set-ups don't have crosstalk issues anyway. There was no difference perceptible to me once I'd volume matched and the measurements I took bore this out. Its nice to have the option – but sonically I don't hear any benefits.


These comparisons were all done with the X5iii this time, (no EQ) – and volume matched using a calibrated SPL meter and fixed 1kHz test tone first. I could have used a number of different DAPs but I'd been using the X5iii a lot this week (for its review), and simply wanted something not too bright. I wanted to compare against some reasonably well known IEMs in a similar price and signature bracket – so I chose the Meze 12 Classics, Fidue A73 and Dunu Titan 5. And because (IMO) the F9 performs so well for its price bracket, I also put it up against the $200 P1, $250 Alclair Curve and $700 HiFiMan RE800.

FiiO F9 (~USD 99) vs Meze 12 Classic (~USD 79)

The Meze 12 Classic has a cartridge style with a wood body. Build, fit and comfort are very good. However, the FiiO F9 has the better overall build materials, quality, and it has the benefit of replaceable cables, and the choice of two. It also has the better on-cable controls. Comfort goes to the F9's more ergonomic shape (although both are good).

Sonically they are similar in their overall balance. The F9 has more low bass extension, and more lower treble impact. I really rate the Meze 12, it is a brilliantly balanced non-fatiguing signature. The two are variations on a similar signature – with the major difference being the lack of lower bass impact, and the F9 having that extra zing in the top end. If I was judging purely on default sound, I'd probably take the Meze. If I take the rest of the package into account, the F9 draws even and probably goes ahead. If I lessen the 7 kHz peak on the F9 (simple EQ), then no contest – the F9 is the much better deal in my eyes.

FiiO F9 vs Meze 12 and Fidue A73Frequency comparison
FiiO F9 (~USD 99) vs Fidue A73 (~USD 120-130)
Build materials are in favour of the FiiO F9 with it's alloy body vs the formed plastic of the A73. Ergonomics and fairly fit are evenly matched – both are comfortable to wear. The smooth lipless nozzle on the Fidue means you may be slightly limited on tip options. The FiiO F9 slips ahead on cable options (including the fact that its replaceable and has better controls).

Sonically the two are again quite similar with main differences being the warmer bass signature of the A73, and the position of their respective lower treble peaks (F9 at 7 kHz and A73 at 9 kHz). The two actually sound really similar with most tracks – but on default signature I'd take the sightly leaner F9. Under EQ (dropping the 8 kHz slider) is interesting. Both IEMs improve IMO, but again the leaner signature of the F9 is my preferred option. Taking the cheaper price, better build and cable options – this one again is firmly in favour of the F9 for me.

FiiO F9 (~USD 99) vs Dunu Titan 5 (~USD 130-140)

I've talked about the relationship between Dunu and FiiO before – we've seen it in the similarities of the FiiO EX1 to the Dunu Titan 1, and also in FiiO's use of very similar cables and also the brilliant Dunu on-cable ties. So why did I choose to compare the F9 to the T5 – simply because the F9 is so close sonically with the main difference being the positioning of the lower treble peaks.

Both have very good build quality and build materials. Both are extremely comfortable. Both have replaceable cables (although the FiiOs are standard cables where the T5 are more proprietary – longer stem on the MMCX).

Sonically the T5 is a little warmer in the bass, and a little more prominent in the mid-range. They both have a heightened upper mid-range which makes female vocals brilliant. Both also have lower treble peaks which some may find troubling (T5s is at 6 kHz). Interestingly enough the lowering of the 8 kHz slider (EQ) again helps both IEMs. Hard to call a winner based on sound – especially after EQ. But in terms of overall package (especially with price taken into account), again the F9 takes it.

FiiO F9 vs Mee P1 and Dunu T5Frequency comparison
FiiO F9 (~USD 99) vs MEE Pinnacle P1 (~USD 199)

So what happens when you pit the F9 against arguably one of the best IEMs (MEE P1) in the sub $200 range? Both earphones have exceptional build quality, ergonomics, and comfort. The both have replaceable cables – the F9 having balanced vs the MEE P1's HQ SPC cable. The MEE P1 is definitely harder to drive. So far – the two match nicely.

Sonically the MEE P1 has a warmer slightly more V shaped sound, and doesn't have the lower treble peaks. Both convey detail well, but with the MEE P1 you get more warmth and also less etch. With the F9, you get a leaner more linear bass and a signature that sounds slightly cooler overall, plus having that spike around the cymbal area. On default sig – I'm MEE P1 all the way – it just has more balance in the upper registers. But EQ the spike out of the F9 and take into account the price, and you do have an IEM at half the price which can go toe to toe.

FiiO F9 (~USD 99) vs Alclair Curve (~USD 249)

I know this is getting a little out of the F9's depth, but what happens when I put it against one of my favourites in the sub $250 bracket? The Alclair Curve is the most ergonomic IEM I own (and yes this one I do own). Both IEMs have fantastic build quality – with the F9's shell being alloy vs the plastic/acrylic shell of the Curve. Both have replaceable cables. Both have exceptional comfort. The F9 of course has the balanced cable option – the Curve isolates much better.

Sonically these two have very similar signatures. Linear well extended bass, overall balanced signature, a bump in the mid-range, peaks at 7 kHz. The main difference is that the Curve has better overall balance, where the F9 is a little more coloured (especially in the upper mids and lower treble). Again dropping the 7 kHz peak makes the F9 a much better IEM, and it is not embarrassed in this company. For me – I'd still pay the extra and take the Curve. But the F9 shows incredible value for money – and that’s why I chose this particular comparison.

FiiO F9 vs Alclair Curve and HiFiMan RE800Frequency comparison
FiiO F9 (~USD 99) vs HiFiMan RE800 (~USD 699)

Some of you will look at this and ask me why I chose this comparison. If you take a look at the graph, you'll see why.

Both have very good build, fit and comfort. The F9 has replaceable cables and a choice of SE and balanced. The RE800's cables are fixed, but the revised edition will have replaceable cables.

The similarity in signatures is unmistakeable and both are very close to reference signatures with one glaring fault. Yes you guessed it – the 7 kHz peak. Again with EQ nulling this peak down, both are simply incredible sounding monitors. But here's the kicker. The FiiO F9 is 1/7th the price of the RE800. You could buy the F9, an X5iii, a 128 Gb card, and still have more than $100 to spend on music of your choice.

And that is the real beauty of the F9 – its value proposition.


By now you'll already know where I see the strengths of the F9 and one glaring strength is in perceived value. With the F9 its simply off the charts. This is an IEM which can comfortably go toe to toe with IEMs at multiple times its price. I would go so far as to declare the F9 as one of those IEMs which may well set a new bench-mark in the quality/price ratio.

If these were on the market when I was originally looking to buy a higher end pair of IEMs (I eventually started with the Shure SE425 and later the SE535), I doubt I would have spent the money I did. The only thing FiiO need to do with these is take that 7 kHz peak down a little (5-6 dB). Do that and the F9 is a solid gold winner.


FiiO has really pulled out some surprises with their IEM releases this year. But the F9 is a warning shot across the bows of a lot of IEM makers. It is a serious contender at a very low price (almost entry point for some).

It combines good build and design, great ergonomics, and well thought out accessories, with an exceptionally mature and balanced signature. Its one downfall (IMHO) is that in reaching for additional detail, they simply made the error of overemphasising a narrow band at 7 kHz. It is easily EQ'd out, but it really shouldn't be there in the first place.

How do you rank these? They aren't perfect – but they've come so close when you take the price point into account. From my perspective (and weighted for value), the F9 are a definite 4.5, and very close to 5 for the price. As close as you can get to perfect on this budget. These won't be going in the review sample box – I'll still be using them regularly. And that should say all you need to know. Recommended without hesitation.

Hey man, I'm looking for an upgrade to my KZ ZS3. It's too bassy for my taste. I love my Grado SR80e and my Shure SRH440 so it's safe to say that I love treble but I appreciate the quality of bass that they produce - fast, grunty, and accurate.

This could be the one. I've seen reviews on the FH1 but that might have more emphasis on bass.

I'm capped at 100 USD. If you have other recommendations at this price range, feel free to list as well, or send me a PM.

Thanks as always!