With 6 drivers, 3 crossover switches and a custom low pass filter tube design, and a 3D printed enclosure, FiiO takes their IEM design to new heights. Read on for the review!

We’d like to thank FiiO for sending this unit for review. This review remains the honest and independent opinion of myself. The FiiO FA9 can be bought for 499.99USD.

I think at this point, the readers of the site should be pretty familiar with the FiiO brand name. Starting off as a budget studio brand from China, they’ve quickly gained a reputation as one of the most budget friendly choices with increasingly top notch audio quality. I didn’t get a chance to review their FH7 which also seems like a further step into the high end market but I’ve been very impressed with the FA9.


2.Packaging & Accessories
3.Design & Ergonomics
4.Detailed Sound Review


Driver Type6x Knowles BA
SWFK-31736 (high frequencies)
EJ-33877 (mid frequencies)
HODVTEC-31618 (lower frequencies)
4-way electronic crossover
Frequency Response15Hz ~ 40kHz
Cable8 strand braided silver cable, MMCX connectors
Plug3.5mm L-plug

Packaging & Accessories

The packaging is pretty much what I’ve come to expect from FiiO at this point – a high quality, solid, and lightly textured cardboard box, with multiple layers of black protective foam that frames the shiny IEM beautifully and lifts up to reveal a vast array of accessories underneath.

It seems that they’ve upped the ante slightly further since my last review of the FH5 which already impressed me. Though the soft carrying case remains the same grey bag which I actually find to be slightly undersized for the IEMs when their thick cables are all wound up, FiiO has also added a nicely designed hard faux-leather case to the accessories.

Inside the case is a nice magnetic cable clip as well as a special cleaning brush with a small screwdriver tip on the opposite end. Though you can probably use it as a screwdriver, it’s actually for the you to toggle the tiny little switches on the IEM.

Design & Ergonomics

Compared to the slightly rotund and heavy metallic shell of the FH5, the FA9’s flawlessly 3D printed plastic shell is wonderfully light and ergonomic, and printed by a Chinese 3D printing specialist called HeyGears (as noted on the back of the packaging box). Don’t be turned off by the word plastic though; the quality of the shell is impeccable and every inch of it is made up of a smooth, translucent smokey colored resin that lets you see through into the internals of the IEM.

Take a moment to admire FiiO’s custom “80.6mm ultra long” low pass filter sound tube that doesn’t rely on the usual damping filters. Instead, they twisted the tube multiple times to get the bass frequencies they wanted to get through, and the resulting sound is pretty darn good.

At the face that looks upwards when worn, you’ll find the 3 tiny plastic switches that this whole IEM is about. They’re arranged in a neat row with small but clear “1,2,3” labels for each switch under them. However I have no idea what ON and KE stand for but have not found it essential to know so. Toggling the switches is very simple; a light push with the tiny screwdriver-brush supplied by FiiO inside the IEM case will easily push it up or down.

Aside from the shell, the seamlessly integrated faceplate also features a unique triangular shaped chiseled pattern. It catches light from all directions, creating a cool shimmering effect when you turn it at different angles. I was a little hesitant to wear something so shiny at first, but it grew on me and I don’t think it looks gaudy at all.

I’m very happy with the gorgeous 8 strand braided silver cable that they supplied – it’s soft and non microphonic but still thick and tense enough that it untangles extremely easily. The MMCX attachments are also colour coded for easy recognition and look and feel sturdy.

Detailed Sound Analysis

(Standard switches)
Straight out of the box, my first impression is: Slightly mids centric, slightly above neutral bass quantity with a very natural warmth to the sound. In fact the overall tone is quite warm and unlike many balanced armature designs I’ve listened to before which tend to be a little harsher around the edges and have more odd order harmonics. The feeling I get is that this product was tuned with a lot of thought and care put into it, and not just some multi driver BA IEM bashed together for a quick cash grab. I found absolutely no mechanical harshness even when I pushed the volume higher and I thought to myself – I could actually see myself using this over some of my hybrid and dynamic driver iems.

The big driver (no pun intended) of making a decision like this is undoubtedly the quality of bass. While the FA9 still doesn’t shoot out deep, resounding subbass rumble typical of DD design, it is superior in being more exact in bass impact and controlled in the subbass while keeping the same smooth, warm, and natural presentation. I honestly think I could have been tricked by the effortless quality of the bass if I didn’t know it was a BA configuration. Perhaps that is the strength of their dual woofer, filterless winding sound tube low pass filter design.

The FA9 excels at being gorgeously well balanced in every frequency range, and having a slight analytical tinge without being overly so. I find that it hits the right spot between the typical dynamic driver and typical balanced armature design tonal qualities. With a lack of a better description, vocals simply sound very natural. Not the most rich, intimate, and luscious vocals ever, but there’s a good amount of detail that brings out the subtle  details of the singers breath and enunciation.  The FA9 definitely hits the right spot for someone looking for a well balanced IEM that will work with all genres of music.

Where the FA9 may be lacking is undoubtedly its soundstage. In my experience of listening to items, I’ve often found that the ones that sound most effortlessly natural and balanced tend to have less of a giant sound stage effect and the FA9 does fall into this category for me. The FA9 has a rather middling sense of sound stage with above average height and width, but it’s honestly not where it shines.

However, despite having soundstage slightly narrower than what I’m used to, I really enjoy the very accurate imaging and positioning of the FA9, skillfully defined by the 6 balanced armature drivers inside. And, there’s actually a subtle way to boost the soundstage, and that is with the switches at the top face of the FA9.

(Boosted Highs mode)
Personally, the boosted highs mode is my favourite out of the 3 settings, not including standard mode. I’m in no way a treble head, and in fact I prefer more warmth in general. Switching to boosted highs gives the upper end a little extra sparkle that elevates the listening experience for me that much more. It’s most noticeable in the shimmery sounds of cymbals and the fine details of vocal ranges, and there’s also the added benefit of a slightly taller soundstage. Everything just sounds more dynamic and musical in this setting, and my suspicions were confirmed with measurements which showed that the bass also got a slight (perhaps unintended) boost, though not as much as the Pop and Bass Boost settings. For me, this is the perfect balance.

(Boosted Bass mode)
On the other end, boosted bass also gives a noticeable bump to lower end impact along with more subbass presence. Despite what I mentioned earlier about the FA9’s bass sounding quite natural for a balanced armature, the bass still has a rather sharp falloff towards the subbass frequencies. The bass boost does indeed give more bass quantity but it also accentuates that flat quality of balanced armature bass, and as someone who thinks dynamic driver bass is much more natural sounding, I can’t really stand it. I would caution using the bass boost mode too liberally, and limit it to music that doesn’t already have lots of bass because you will notice the unnatural quality of it.

(Pop mode)
While this is technically the most dynamic sounding of the 4 modes, like I said earlier I prefer the Standard or the High Boost more than the Bass and Pop ones as their boost to the low frequencies is a bit too much for my liking in this IEM. However, I think it works well for genres that aren’t already very heavy on the low end.


Notice how the cyan coloured line also has a slight boost in the low end – it’s not a pure treble only boost, but I’m not complaining!



  • Beautiful design
  • Gorgeous build quality
  • Quite close to neutral sound quality and let’s you adjust by 1-2dB for a subtle but noticeable bass or treble boost.
  • Warm and natural sounding for a balanced armature design
  • Plenty of ear tips to choose from


  • Not the most dynamic sounding, but it’s still relatively musical for a neutral tuned IEM
  • Bass sounds unnatural with too much boost sometimes

The FA9 has been my daily driver for weeks now. It was a breath of fresh air to use something relatively neutral, with such a tight bass response yet still sounded quite natural. While I do sometimes miss the bigger, robust musical sound of some of my hybrid IEMs, the FA9 lets me focus more on the details throughout all the frequencies of my music without sacrificing too much musicality. The switches are rather subtle and don’t change the entire sound but I think avid listeners and audiophiles will still find it a useful tweak to give their listening experience just that bit of low end oomph or high frequency sparkle that they desire. All in all, a good and well balanced IEM without too big of a price tag. I would recommend it to people looking for a neutral audio tuning with just a pinch of musicality.