Fiio FX15 Review

Fiio FX15 Review

Fiio has their hands in a lot of different audio products, including IEMs. They have a few different models in the mid-budget range, like the FH9 and FD7. They have a solid lineup, and now they’re adding something a bit higher tier. The FX15 is a new electrostatic IEM that costs $749. It’s rare for Fiio to venture in this range, so let’s see if it’s capable of anything special.

Fiio FX15 Items

What You Get

  • Manual*1
  • HB5 carrying case*1
  • Interchangeable plug silver cable*1
  • Vocal ear tips*3 pairs (S/M/L)
  • Bass ear tips*3 pairs (S/M/L)
  • Dual flange ear tips*2 pairs (M)
  • Foam ear tips*2pairs (M)
  • Balanced ear tips*3 pairs (S/M/L) (M pre-installed)
  • Headphones unit*1
  • Magnetic clip*1
  • Cleaning brush*1
  • MMCX quick release tool*1
  • 3.5/4.4mm interchangeable plugs *1 (4.4mm pre-installed)
  • SpinFit ear tips *3 pairs (S/M/L)
  • HS18 ear tips *3 pairs (S/M/L)

Fiio FX15 single

Look & Feel

The FX15 comes with a glossy design and an ergonomic shape. It’s a custom 3D printed shell that’s easy to loos at, featuring a smooth resin surface, paired with a great cable. The outer shell is a little narrower than some of their other models, and it makes for an easy insertion in the ear. From there on, the FX15 should have no problem sitting in your ear naturally, with good isolation and comfort.

Fiio FX15 cable


There are a few different drivers within the FX15. It’s a tribrid system that features a 10mm dynamic driver, Knowles mid and treble balanced armatures, and Sonion electrostatic tweeters. With the top switches, you’re able to turn these electrostatic drivers on and off.

Fiio FX15 pair


While the FX15 gives you a good amount of width from left to right, where it really impresses is its separation and layering. It has a fine wingspan, but the air between each sound makes this soundstage so immersive. It forms a bubble around your head while keeping the performances close to you. This makes everything in the mix appear individualized, sorted precisely to its indented position with room to float around in. There’s a dimension to this sound that gives each track a breath of life.

Low End

The bass on the FX15 is very enveloping. It enriches the sound signature with a hefty sub-bass boost, adding a satisfying amount of depth. There’s a fullness to the tone where the frequencies are thick and engrossing with a powerful slam. You can feel the weight of each element support the wide surface area of its sound. It feels like the bass has a specific origin, and blossoms into the mix from that point. While it’s definitely a slam dunk for bassheads, it also never feels overwhelming. It’s a controlled timbre that makes everything sound believable. The texture of the bass is what’s going to bring out the tone significantly.


In the mids, all of the sound elements are given plenty of room to express themselves in. Each instrument has a clean identity to it, helped by the refined frequency content within the midrange. The transparency of this section adds to the expressiveness provided by the reproduction of these frequencies. Everything is clean and houses a few accentuated regions in the upper mids. It’s a crisp range of detail that brings out lively performances all around.


There’s a lot of concentrated detail in the highs that exhibit a respectable amount of heat. Although the frequency content is controlled well, the timbre can get quite peaky at times, and their surface moves towards brightness. I found this hot texture to feel like it was overreaching at times, but it wasn’t a consistent tone.


The FX15 is a great entry in Fiio’s lineup of IEMs. It features some colorful textures and great transparency in certain frequency regions. The bass and separation are definitely highlights for me, as well as its great design and wealth of accessories. Some of the high frequencies might not win everyone over, but the electrostatic switch should make those frequencies easier to digest. Its price is the only big ask for these IEMs, but it comes with a lot of value in addition to its great sound.

Pros Cons
  • Great separation
  • Impactful bass
  • Lively mids
  • Comfortable fit
  • Good cable
  • Many accessories
  • Sometimes overly bright mids
  • Competitive priceĀ 

The Fiio FX15 is available at Audio46.

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Alex S. is a sound designer and voice-over artist who has worked in film, commercials, and podcasts. He loves horror movies and emo music.