Review: FiiO F9 – Prime


The FiiO F9 has 1 dynamic driver and 2 balanced armature drivers under the hood. There are lots of hybrid designs in the market now, yet the F9’s strong suit is the price. But of course the configuration is not everything, there needs to be a good cohesiveness, good control of the dynamic driver and good precision from the BA drivers.

Does F9 tick those boxes? Let’s find out.


The FiiO F9 has good amount of bass and if you like bassy type of IEMs, there’s a good potential for you to like it. Thanks to the dynamic driver it has a good amount but it’s not something I would call “bass heavy”. On the other hand, there’s certainly a focus on low frequencies. They’re the focal point most of the time, making their presence heard, especially on bassy recordings.

Mid & subbass balance is good, altough I think the midbass is ahead in terms of quantity. It’s important to set your expectations right in this price range so I think it’s quite nice. Is it nicely controlled? Sometimes yes, sometimes no. That depends on the source and the recording but you shouldn’t expect top notch control over the bass, like Mid-Class or TOTL hybrid IEMs.

The important thing here is the midbass. Altough it’s a midbass focused IEM, the midbass hump problem is almost non existent. I say almost because it’s not perfect. There’s a small midbass hump, yet I don’t think it will bother and you can use a small amount of EQ to make it flatter. Fortunately there’s no obvious bleeding on this part, so the mids can shine if they’re asked to. Not on a high level but you can’t ask more than this for the money. So fairly good separation between bass and mids but it could’ve been a little better if you ask me. It’s positive to hear that subbass is not overpowering, but just a little flatter midbass and slightly more kick from subbass could’ve made this IEM even better in my opinion.

The bass doesn’t reach very deep and altough the texture is not too bad, again I think a little more bass kick from subs would’ve been nice. Instead, the focus usually is on the midbass. That makes the IEM just a little slow for fast paced music genres. But that part can be better or worse in proportion with the source quality. But I should say bass is not artificial and not overly elevated as a whole. This is a natural bass response, maybe a little bit better tuning can be done in the future to make it better.


This is not a mid monster and there are reasons for me to say that. The mids are slightly recessed overall, making the F9 a slightly V-Shaped sounding IEM. Mids are not too distant though, there’s still good resolution and definition in this part. Mids also contain very good tonality and naturalness so it in no way like is some entry level IEMs that sounds artificial or thin. The mids are full, dynamic, transparent and coherent. Along with good level of dynamism for the price, you won’t be disappointed but in terms of amount, if you like more forward mids in your IEMs than this obviously is not the first choice.

Mids are nicely separated from low frequencies. So despite being a little back in the stage, you can hear the good tonality and transparency across the range. I’m no way in discomfort in terms of mid presentation but I prefer more quantity from the mids. Maybe with a little less midbass presence, mids could shine more with the F9.

But for 100$, there’s no need to be harsh on this IEM really. In the past I heard worse or similar presentations with more expensive IEMs. However there’s a peak that lies down on upper mids & lower treble that needs to be equalized to some extent. Foam tips can be useful here, making them smoother and more coherent by sucking out those peaks. Is it too discomforting with sibilance? No, but it for me personally needs to be addressed. Either with foam tips or EQ.


Lower treble has some amount of peak as I’ve said, you either could face it or not, depending on the recording and source quality. But once you solve that with EQ or foam tips, you can focus on the good treble extension, resolution and detail retrieval. Treble is quite prominent, almost the same amount as the low frequencies, but not harsh except for the lower treble. The cymbals can be harsh for you so be aware. It’s good to tame down that part with EQ.

Highs have good clarity and resolution, and also can sound nicely articulated. The treble quality of the FiiO F9 is very very good and you’ll be pleased to hear the details from it, especially for this price. Highs give good lift for this IEM to sound airy and open, so it doesn’t sound congested in any way whatsoever.

Treble also has good positioning with being at the right distance and not in your face. It usually sounds quite refined and has good control on upper treble. The roll off in this part is slightly apparent but it’s not something to complain about because the roll off isn’t too much. So extension is good in my opinion. Could it be better? Well it can always be better, but not for this price level.

Overall, except the lower treble region (which you can easily sort out with giving -2/3db on 8khz) treble is very nice with the F9.

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A keen audiophile and hobby photographer, Berkhan is after absolute perfection. Whether it is a full frame camera or a custom in-ear, his standpoint persists the same. He tries to keep his photography enthusiasm at the same level with audio. Sometimes photography wins, sometimes his love for music takes him over and he puts that camera aside. Simplistic expressions of sound in his reviews is the way to go for him. He enjoys a fine single malt along with his favourite Jazz recordings.


  • Reply October 10, 2017


    “To me the balanced cable is clearly better to the standard cable. You get better imaging and separation, better staging and better frequency response. If you have the F9, go straight to balanced and don’t look back.”

    Well unless you’re using a source with massive impedance difference, then there is no measurable change in frequency response. I know, I’ve measured them. There is also no change in imaging, staging or separation – if you volume match and blind test. I take it when you were comparing, you didn’t volume match? What was the source – and does it have a big difference in impedance between SE and Bal?

    • Reply October 10, 2017


      I’m not a total believer in measurements, and I don’t really like to approach the items completely in a technical way.

      As soon as I’ve heard the balanced cable I was convinced that it sounded better. So I just trust what I hear and pass on that information in my reviews.

      The sources were WM1A, Q1MK2 Amp and Shanling M3S.

      • Reply October 10, 2017


        How can you not be a believer in measurements? they are more accurate than our ears – and they don’t have our brains to filter them. I checked your DAPs. The FiiO and Shanling both use the same circuits, so they shouldn’t sound any different balanced or single-ended. I have the FiiO and the F9 measures exactly the same frequency response on both balanced and single-ended. Sony don’t publish full specs, so can’t really comment on that one. Anyway – suggest you change the review – and take out the bit about frequency response, as it is simply not correct. Otherwise good review 🙂

  • Reply October 10, 2017


    I am with Berkhan on this one regarding the balanced output

    • Reply October 10, 2017


      Wish we were on the same continent Lieven – would love to set up a controlled volume matched blind test, and we could compare notes after that 😉

  • Reply October 10, 2017

    dale thorn

    I wonder, if the audio difference were clear enough, whether measurements would confirm that exact difference? Some of these things are elusive. But I agree on volume matching, which would need to be closer than 1/2 db.

    • Reply October 11, 2017


      Depends on the difference I guess Dale. If its in frequency response – yes definitely it will show up. Imaging, separation, and perceived sound-stage width/depth can have some things show up in frequency (generally if it’s brighter, or cooler tonally, we tend to perceive a bigger stage and better separation (makes sense when you consider the added clarity). But its not the whole story, and definitely when I volume match (to 0.1-0.2 db) and blind test (my wife and kids humour me with the switching), I can’t personally tell a difference. I also accept I have cloth ears 🙂 – but I know thats not the whole story either.

      If we look at separation and staging – and then check against the specs (I’m using X7ii here for the example), between balanced and single ended:
      SNR on SE is 116 dB and on balanced is 119 dB. Both are beyond what we can hear – so no difference. Both have THD measurements at 0.003% = beyond our hearing. You’ll get a magnitude more distortion from your earphones. Now the important one – crosstalk (channel separation). SE is 73 dB and balanced is 97 dB. That must make a big difference – right?

      Well not really – The FCC minimum channel separation/crosstalk spec for FM Stereo used to be 29.7dB…yes, that’s right, 29.7. It had to do with how the signal was generated and handled, but 30 – 40dB wasn’t hard to achieve, and 50dB wasn’t uncommon.

      The bulk of what is perceived as stereo separation happens above 20dB with decreasing detectable improvements above 30dB or so. It’s almost impossible to detect separation improvements above 40dB. Localization of a phantom image depends less on channel separation and much more on relative intensity and inter-aural time delay of the sound, and human hearing response at different angles

      So….long answer…separation above 40dB doesn’t improve sound quality, below 40dB it slowly degrades, the final separation is equal to the device with the least separation in the system. Once degraded by a device, no device following it can restore separation.

      As you can see, SE crosstalk at 73 dB and balanced at 97 dB actually means nothing – we can’t hear the difference.

      So where are these magical differences? I agree that impedance can change frequency response – mostly with multi BA set-ups, and generally with crossovers involved. The F9 though doesn’t change – even with the X7ii’s impedance difference. So where are the perceived changes coming from. I have no doubt “Berkhan hears them” – my question though is are they actually real or expectation?

      • Reply October 11, 2017

        dale thorn

        OK – I see where the lines get drawn now. Between the maximum detectable difference at ~40 db and 73 db is a huge dynamic. So the only conceivable thing that could enter the audible range (all other things like volume being equal) is if something reflected back into the audio or modulated the analog signal somehow. That would be a defect rather than a feature though. This is interesting. I’ve never used a balanced rig, so maybe I’ll try this at some point.

  • Reply October 10, 2017


    Fiio F9 or Magaosi k3 Pro?

  • Reply October 11, 2017

    Bill Ruschmeyer

    Sound is so subjective. For me i like transparency, accurate tonal bass and a little forward sound, that is what draws me in. The next person with the same iem’s and source could be completely different, and guess what the measurements don’t change. To me the only measurement that matters is my ears and no two are alike.

    • Reply October 12, 2017


      If sound is completely subjective, then why read or write reviews…

    • Reply October 12, 2017

      dale thorn

      Different genres of music, and/or different eras of recordings, can make a much bigger difference in sound than just the difference between headphone A or B. There are so many factors, and you have to take them into consideration when reading reviews of things you want to purchase. Of course, when researching new amps and headphones, you can also explore those other genres of music that different reviewers are featuring in their reviews.

  • Reply October 21, 2017

    Yannick Khong

    Thank you for this review. How does it compare to the Oriveti New Primacy as both share hybrid drivers?


    • Reply October 23, 2017


      I haven’t experienced the New Primacy, sorry.

  • Reply November 3, 2017

    Shubham Garg

    I think these headphone might offer some competition in the market.

  • Reply November 9, 2017

    ketan singh

    How are they compared to similarly priced 1more triple drivers?

  • Reply November 15, 2017


    Good information, it helps a lot!!

    Thank you!!

  • Reply December 10, 2017

    Harpreet Singh

    I’m using fiio products like fiio audio DAC for PC and I loved the build quality and performance is also superb and i hope fiio F9 also offers great value for money.

  • Reply December 12, 2017


    How does this compare to the oriolus forestini especially towards the bass? Its priced quite in a similar price range in my area , just curious which would u recommend?

    • Reply December 21, 2017


      Forsteni has better bass quality and it’s much better in other areas too. But the F9 Pro is very nice you should wait for that review 🙂

  • Reply December 20, 2017

    Rahul Malhotra

    I think its great choice for anyone looking for headphone over 4K-5K INR.

  • Reply December 20, 2017

    Rahul Kolkar

    First of all Hats off for making such an amazing blog! I was in search of the best earphones and landed on this page,found all the relevant things!Nice content guys keep it up

    • Reply December 21, 2017


      Thanks a lot. Keep following us 🙂

  • Reply March 5, 2018


    I think this is one of the best choice!!

  • Reply June 2, 2018


    is this comfortable to wear

  • Reply July 10, 2018

    tarique ghani

    Does it fit into the ear?

  • Reply December 25, 2018

    Best Green AC

    I never found one that provides best comfort and nice sound but it is looking good and I think it will be better than others……!

  • Reply January 10, 2019

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    Carrier AC

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  • Reply January 10, 2019

    Sand Mandala

    I always experience that wires are cheaper then headphones so I am looking for the material that doesn’t broken in the winters.

  • Reply January 10, 2019

    wool socks

    Anybody who like to enjoy music and dance with hi – fi music, must need good quality headphones like me. I bought that one in the article and it is outstanding.

  • Reply February 10, 2019


    These are really amazing. Good to see something new in market. And price is very reasonable. Hoping these are comfortable to wear and expecting good sound. But informative blog. Thanks.

  • Reply February 13, 2019

    stuart garner norton

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  • Reply February 14, 2019

    stuart garner norton

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  • Reply April 12, 2019


    I was looking for such deep review of fiio f9 since long time, thanks for explaining all the facts.

  • Reply June 3, 2019

    Akshay jagtap

    Thanks for sharing this amazing and informative post. I enjoyed reading this information.

  • Reply June 3, 2019

    Disha Shengale

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  • My friend mentioned to me your blog, so I thought I’d read it for myself. Very interesting insights, will be back for more!

  • Reply July 29, 2019


    You are writing some Amazing tips. This article really helped me a lot. Thanks for sharing this blog

  • Reply August 2, 2019

    Smruti ranjan

    Thanks for your Amazing tips and deep information. It really helped me and I enjoyed the reading.

  • Reply August 5, 2019


    I really love this FioO F9 and it’s sleek and stylish design, and potentially a higher level of sound than their first couple of models. I will buy it definitely it’s worth of money.

  • Reply August 29, 2019

    Green Coast

    Sound is so subjective. For me i like transparency, accurate tonal bass and a little forward sound, that is what draws me in.

  • Reply September 13, 2019


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  • Reply September 24, 2019

    Juli kim

    This review is great and FiiO F9 has 1 dynamic driver and 2 balanced armature drivers under the hood are the best choice. great one. Thanks for this informative post.

  • Reply September 24, 2019


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  • Reply September 28, 2019

    Let Stack

    I never found one that provides best comfort and nice sound but it is looking good and I think it will be better than others……!

  • Reply October 9, 2019

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    I think this is one of the best choice!!

  • Reply October 23, 2019

    Duttaji Technical

    Very Good article

  • Reply January 1, 2020

    Ankit Varma

    I have used it and its amazing

  • Reply January 8, 2020


    Your blog is amazing. You had done hard work for this and it really reflects from this blog. Helpful review it is.

  • Reply January 12, 2020

    Riann Will

    This is very cool but also very costly. At present I need to wait for this. Bring some thing for a common man.

  • Reply March 17, 2020

    Varun Rana

    I think these headphone might offer some competition in the market

  • Reply March 19, 2020

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  • Reply March 20, 2020


    I suppose it’s likely that these headphones offer some industry pressure.

  • Reply March 22, 2020


    I suppose it’s likely that these headphones offer some price competition.

  • Reply March 24, 2020

    sushant thakur

    It looks costly but effective.

  • Reply March 24, 2020

    AM Varghese

    I am using this. Its main attraction is its superb design.

  • Reply March 28, 2020

    Digital Net99

    I think these headphone might offer some competition in the market.

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