FiiO X5iii: the giant killer that wasn’t

Pros:  Size is nice in the hand, solid build, 2 micro-SD slots for tons of storage, Google Play Store, minimal skinning on Android, good functional interface, Quick Charge, excellent USB DAC function, full-featured

Cons: Sound is very mid-fi, hiss with sensitive IEMs, button layout not terribly ergonomic, weak/poor Bluetooth, limited amplification, crowded bottom end, coaxial digital out without with lame adaptor

List Price: $399

FiiO X5iii rating


Thanks go to FiiO for organizing a worldwide tour of the X5iii and letting me join it. After this is all over, this player will be heading back to ea audio, FiiO’s UK distributor. You can buy the player there too.


I have done a little bit of FiiO listening in the past at shows. I liked the X3ii. I thought the X1 was excellent value for money. I wasn’t really into the sound of either the X5ii or the X7. When I last met FiiO folks I was interested in reviewing their newly released (at the time) balanced cables. I didn’t like them. They had terrible ergonomics and a bit of a thin treble happy sound—consequently other reviews of gear that I like a lot more have taken precedence for writing up instead of the balanced cable reviews. I let FiiO know that I wasn’t likely to review those samples, but I’m a bit disappointed to not have done so. I may still do it.

My history with FiiO is one of not generally liking their house sound, but when I saw that they were releasing a DAP that was Android, with two microSD slots, Quick Charge, WiFi, Google Play Store enabled, and rocking two AK4490 chips I was more than intrigued. We’ll see if the intrigue carries on to affection.

Useability: Form & Function


The unboxing experience was somewhat reduced due to this being on a tour. Folks just slam things back into the case and I have no idea what it originally looked like. What is included though is quite impressive. You get two cases, one pleather and one TPU. I’m not really a fan of either, but it’s a good include. Of the two cases I liked the pleather best, but it doesn’t have the kind of quality that the optional Opus #3 case has.

The player comes fitted with a tempered glass, which is a first for me. Good thing too, as when I took off the case I thought that one of the previous reviewers had cracked the screen whilst practicing their circus routine. Luckily it was just the screen protector.

In addition to the screen protector and cases FiiO includes a 3.5mm to coaxial female adaptor, and the ubiquitous micro-usb cable. Personally, I prefer having an optical out, and if an optical out isn’t provided, I’d rather have a direct to coaxial adaptor rather than one that makes me supply my own cable. It’s a portable device, I’m not likely to be carrying around a full-size coaxial cable and I’m not likely to need a big length. In this position, the approach that iBasso took with the DX-50 is preferable—I don’t know if they still supply 3.5mm to coax adaptors.

Feature Comparison

Feature FiiO X5iii Opus #3 Aune M1s
Price $399 (£389)  $899  $249
DSD256 X
DSD128 X X X
DXD352 X X (2) X
External DAC X X
Digital Out Coaxial with adaptor cable Optical
Equalizer Yes Yes
Google Play Store X
APK Sideload X Not yet (3)
Search Music X
Scan 200GB microSD <2min <2min <1min
Bluetooth 4.0 X X
Bluetooth Range (4) 6-7m (~20’) 6-7m (~20’)
Replay Gain X
Gain Settings 2 2 3
Internal Storage 32GB 64GB 0GB
Maximum Storage 544GB 310GB 256GB
Quick Charge Included

(2 hours, tested)

Case Included 1 TPU, 1 Pleather Not included Not included
Screen 3.97” IPS panel (480*800) 4” IPS panel (480*800) 2.4” IPS panel
Screen protector Tempered glass (applied) Plastic



(not applied)

Body Aluminum and glass Aluminum and plastic Aluminum
Power Output (1) 2.8 Vrms

(250mW @32Ω)

3.0 Vrms  

(~280mW @32Ω)

2.4 Vrms

(180mW @32Ω)

Battery Size (Time) 3400 mA ( 4000 mA (~8.5 hours) ~11 hours
Dimensions 109*63.5*15.3mm 117*74*18mm 126*55*14.8mm
Weight 165g 220g 147g
(1) Converted using this where values were given in mW, all numbers for 2.5mm balanced output. (2) The Opus #3 plays 32 bit DXD352, but this is not listed in the specs anywhere. (3) Technically, you can do this, but it is unstable and absolutely not recommended for anyone at this point. Don’t do it. You’ve been warned. Wait for new firmware. (4) Tested with Lear BTC-01


The lines are striking and etched lines from the Astell & Kern school of DAP design, though applied only on one side of the DAP. The rest of the DAP is just like any other rectangular brick of metal. The material choice of Zirconium and the sand blasted surface give a nice texture to the body.

The asymmetrical design may be partly responsible for the awkward fit of the pleather case, as the single sided hump makes it difficult for the structure to pull even. The alternative TPU case also suffers in the aesthetic department. First because TPU is rarely very attractive and second because the plugs for the outputs and inputs on the bottom of the DAP can easily have memory effects that make them swing out of their proper slots and just wave around saying ‘hi’ like the really drunk girl at prom.

The glass sandwich front and back are reminiscent of the Cayin i5, another fine Android player, but one that I didn’t have for this review. The front and back have understated designs with a nice dot matrix adorning the front and a four-pointed star motif gracing the back.


The FiiO X5iii has a good size in the hand with a nice weight. The sandblasted texture feels delightful in hand, but this baby was mostly in cases for me, just to protect it.

I had problems with the button arrangement. The power button and play/pause button are directly parallel one another and the fast-forward button was extraordinarily close by in terms of where your fingers go when you grip. On more than one occasion this arrangement led to pausing or skipping tracks whilst switching between DAPs or pressing to turn the screen on. I prefer layouts where the power button is on the top, like the following: Shanling M2s, TheBit Opus #3, Echobox Explorer.

I also was not a fan of having every input and output on the bottom. This can lead to a very crowded layout. I would recommend moving the line-out, if possible.

I use DAPs in a blazer inside pocket quite a bit, and I found the volume hard to reach in this use instance. There are two reasons for this: the headphone jacks are at the opposite end of the player from the volume control, and because of this must be pointed down; and the orientation of the knob means it cannot be turned anywhere but from the side. The best implementation of a volume knob on a DAP for this type of use goes to the Cayin i5, with the Echobox Explorer not far behind. The Cayin i5 only requires one finger in the pocket to turn the knob. Nice.

Build Quality

The build quality is excellent. The metal is solid with a good grippy surface due to the sandblasting. The headphone jacks and line-out do not protrude far, but are not flush. With 2.5mm TRRS plugs, flush matters, as the plug is not very strong due to its diminutive size. The X5iii does well here in almost getting flush, but the Aune M1s does a better job on this as it is completely flush, allowing the plug body to lend reinforcement to the jack.

Operating System

The X5iii has a full Android operating system with the music player as an app. Google Play store comes included right out of the box which is refreshing after seeing both the Echobox Explorer and the TheBit Opus #3 fail to do this. The interface is mostly stock Android with a little theming. Installing apps is simple and they work intuitively with all the standard Android buttons not stomped on.

I like being able to listen to Tidal, and share my listening habits via Facebook and Twitter.

One of my biggest dislikes was the lock screen. I want to open up the player and immediately be in the player.  FiiO should build in the ability to disable the lock screen.

Where I spend most of my time is the music app, and there is good and bad here.


  • Search function. Everyone should do this.
  • Genre tab with option to be organised as Albums or Songs. Everybody needs to do this.
  • Relatively easy to navigate
  • DLNA works okay for CD quality and under
  • USB DAC works excellently and is easy to access via drop down menu of Android
  • Loads of options: display album art, VU meter, lyrics


  • Hypersaturated colour scheme, album art and text is a bit unnatural looking. It’s basically like a TV shop display with no way to make it have more normal settings. Neon grass forever, crap. Opus #3 looks natural.
  • Player doesn’t start in a music playback view, or even library navigation. It has a start screen with access to playlists, library and DLNA sources. Some may like this. I’d rather have one screen and a scrolling option bar.
  • No scrolling option bar. If I am playing an album and want to play a playlist, I have to back up in the menus multiple steps.
  • I prefer having text based menus instead of icons. I understand the reason for icons (better international compatibility), I just don’t like them.
  • Tapping back on a track doesn’t take you to the beginning of the track and slide scrolling with fingers is restrained by case edges. It’s too hard to get to the beginning of the darn track, which can be a pain for reviewers like me. It may be less of a pain for people who aren’t repeatedly listening to the intro of Hotel California and Time.
  • DLNA stutters on high bitrates and has lag issues. Sometimes it just doesn’t work. Not enough memory or processor speed, methinks. 2GB RAM is not expensive, folks. C’mon.
  • Album art view is zoomed and cropped. This sucks, and it is because of button arrangement. This could be fixed by putting the track time in the track scroll bar, and making the scroll bar thinner. Tiled buttons would also allow for a more visually compact layout that would allow the full album art to be displayed.
  • Lots of purchase options for the Viper effects. I would have just left this off, as this is pretty lame.

Most of the problems in the OS I describe could have been resolved through beta testing. Send me your next DAP before it comes out FiiO, I’m not asking for a freebie. I want to help you.

Audio quality

The X5iii is not what previous FiiO DAPs and products have been like for me. Whilst it isn’t a neutral reference due to it’s little bit of bass lift it is transparent with excellent detail. It doesn’t feel laconic like the X7 did and it doesn’t feel dark and brooding like the previous X5 series numbers did to me. This DAP may be exactly what many people are looking for and at a fraction of the cost of many other Android based players, including the Opus #3 referenced in this review. In fact, this player costs the same as the Opus #1 and has far more functionality. It has been too long and too many firmwares since the I listened to the Opus #1, so no comment on the rest of that comparison.

Sound positives:

  • Full bass and mids
  • Good open sound
  • Good level of detail
  • Speedy
  • Not reference bass (positive for many)

Sound not so positives

  • Vocals can be shouty
  • Sometimes guitars get a bit strident
  • Not as speedy as some competition
  • Some details smear
  • Not reference bass (negative for some)
  • Not enough power for HD600, not even close.

As there is only so much time with one of these tour units, I’m going to let the comparisons speak most for audio quality. Everything is relative anyway.


The X5iii did not do well with higher impedance IEMs. I threw both the RHA CL1 and RHACL750 at it and it sounded a bit sucked out in the mids and lacking in bass compared to what these can do with better power. I didn’t try to pair the X5iii with the HD600, as the poor performance with the RHA CL series seems a good predictor of poor performance with the HD600.  I don’t recommend trying this for demanding cans without an amp.

The Noble Kaiser Encore, Unique Melody Miracle v2, and the UERR all played very nice with the X5iii. Dropping down from the top tiers of headphones the X5iii played nice with the Meze 11 Neo and Meze 12 Classics. (the links are to, your shopping helps support the site)

With Bluetooth, I found that the transmitter was not very good. I have had better quality with my cell phone (Asus Zenfone 3) and with my Avantree Priva II transmitter (best transmitter I’ve found). The Audio Opus Opus #3  and FiiO X5iii had similar range performance and basically identical. I tested both with the Lear BTC-01, which I’ve had good results with elsewhere.


Comparisons began with the UERR matched at 76.2 dB using an SPL meter and DIY coupler. Comparisons began in Android Mode and moved to Pure Music mode on the X5iii. All other players do not have a separate setting for ‘pure music.’ Midway through testing I switched headphones to the Noble Kaiser Encore.

Aune S6

First, to be fair, I’ll list off the signal chain for the S6. The S6 was connected to my laptop with the following chain:

Dell Vostro to iFi supplied generic USB 3.0 to iFi Micro iUSB3.0 to LH Labs Lightspeed 2G cable (split power and signal)

I find that this signal chain generally enhances soundstage and note resolution, so the S6 is already getting a leg up, but this would be my use case.

Sloop John B (DSD64). The S6 has a much more transparent and natural sound. The treble sounds clearer and the space in the soundstage is larger. Mids are clearer on the S6 and bass has a more natural feel. The FiiO X5iii sounds veiled in comparison with a bit of recession in the vocal range. Bass is less emphatic on the X5iii.

Georgio by Moroder has a smoother sound on the X5iii, but this also means it has a slightly lower resolution. The S6 has more power and body in every part of the spectrum.

The sound of the S6 is full and organic. The chugging bass on D’yer Ma’ker really shines on the S6. Comparatively, the X5iii sounds restrained. I like the extra body on the S6. However, the X5iii has better definition on those signature chugging bass notes, and the stage seems a little bit more defined. I think in this situation I prefer the pairing with the S6.

On Damien Rice – Elephant the strings have greater body and emotion with very natural decay and timbre. The X5iii is very clear and breathy, but the S6 is soulful. The timbre picture on this comparison is becoming quite clear. The S6 has a more lush, organic sound, but the X5iii is by no means dry on these tracks. Details are excellent on both.

Katherine Bryan — Flute Concerto Alla Marcia, the S6 has an effortless and natural depth to the stage. The width is also greater. This track used to be my treble torture test. Executed right it doesn’t pierce your ears, but has some very high notes on the flute. It also has some fantastic timpani strikes. Both the S6 and the X5iii pass the treble torture test for this track. No shrill moments on either.

On Infected Mushroom – Heavy Weight. The S6 has much greater depth and width and a far more natural flow to the music. It matches the X5iii punch for punch in detail. The sound is just dripping with power. With the power differential in the comparisons, I felt the need to try listening to the X5iii at a much louder volume. So I jacked it 10 points in volume, this should be a roughly 4 dB boost. The S6 was still fuller sounding, but it was a lot closer. It is quite possible that measurement error accounts for some of the differences in sound, but I think it unlikely that it accounts for all of the differences between the two. The X5iii has better detail resolution and precision. Note definition is tighter on all the digital percussive elements that this song has going. The X5iii is a bit faster too. Jacking the volume a bit helps with definition on the X5iii, unsurprisingly.

Audio Opus Opus #3

The soundstage is quite wide on the Opus #3 on Infected Mushroom – Heavy Weight. The Opus #3 might be the most detailed DAP I have listened to and it doesn’t disappoint here. The sound presentation is clear and uber transparent on the Opus #3. The X5iii sounds more restrained with less width in the stage and less height. The sound is also less transparent and textured.  Win for the Opus #3 on this one. Trying the jack the volume test, I find that the Opus #3 still outpaces on details and soundstage width and height. The sound is just far more transparent.

The announcer is further back in the stage and the overall stage dimensions are smaller for the X5iii on Pink Floyd – On the Run, similarly on Time there is more space between the clocks and greater width on the Opus #3. The moving drummer also has greater depth to use. The Opus #3 appears to be outclassing the X5iii when both are operating in Android. Switching to pure music mode the soundstage width of the X5iii improves some. The Opus #3 still edges it here, but it is a closer battle. It’s very close, in fact.  On depth after the switch, the X5iii has a less immediate presentation, but the sound stage isn’t really bigger, it’s just further away from you.

Let’s torture some treble. Kraftwerk – Kometenmelodie2 should work nicely.

Both players let the sound get to the piercing levels it is supposed to achieve. Test passed. The X5iii sounds a bit veiled in comparison, though (we are in pure music mode now).

At this point, to insure that my sound interpretations aren’t just due to having a different volume measurement on the user error prone customs, I switched to the Noble Kaiser Encore and ran through some tracks again. Heavy Weight’s intro sounded a little veiled on the X5iii. The Opus #3 is more transparent with better resolution. The presentation is a bit more intricate on the Opus #3. On the repeat of On the Run the two players are about even. The announcer has equal clarity in both. If anything, I’d say the Opus #3 is a little airier with more spatial resolution, whilst the X5iii has a bit less width and a little bit firmer presentation. On Time there is a bit more depth in the presentation of clocks with greater differentiation in the stage depth on the Opus #3. The Opus #3 is crisper. When the drummer comes in the there is more impact on the X5iii. Both do an excellent job depicting his movement around the stage—the drummer’s dance is full of motion on both players.

So far for me it’s been largely about the treble differences between these two, the bigger stage of the Opus #3 and the greater immediacy and impact of the X5iii in the mids. But what if Meghan Trainor is right? Is it All About That Bass?

To find out, I’m going to throw a couple of my favourite test tracks at it: Massive Attack – Teardrop and Why – Strawberries.  As expected, the X5iii has a firmer and fuller bass presentation on Teardrop. The electronic drums and bass have firmer and fuller body. For bassheads, the X5iii is definitely superior. The bass is still there on the Opus #3, but not nearly as full as the X5iii. Likewise on Strawberries, the Opus #3 has tight and resolved bass, but not the physical or emotional weight of the X5iii. The Opus #3 still has the wider soundstage on this track and the more articulate and detailed presentation, if not more emotional presentation.

Does emotional weight carry on to the mids? We’ll see. For testing emotional weight I like throwing Damien Rice’s 9 album down. I don’t know if there is a male singer who can make my waterworks just flow like Damien Rice. He may have the most emotional male vocal I’ve heard, and those lyrics don’t help either. When testing with Elephant, the Opus #3 is more airy. Guitar picks have more definition, vocals are more delicate while still maintaining emotional weight. Vocals on the X5iii had a tendency to feel a bit more shouty at the same SPL. The Opus #3 is just the more refined player of the two.

Aune M1s

The Aune M1s has a significantly wider and deeper soundstage. It has better note resolution, it is clearer. It sounds better. This is beginning to be a pattern. The X5iii just can’t win any of my duels. Good thing the battles are more like fighting with pool noodles than a real duel.

The X5iii is on the left. Poor kid’s about to be decapitated.

At this point I just don’t have the heart to subject the X5iii to another comparison, so I decide to leave it alone vs. the Echobox Explorer. In the past I’ve found the Echobox to sound as good or better than the M1s, so the FiiO X5iii didn’t really have a chance anyway.

Volume Matching Data

Source IEM Cable SE/


Gain Volume ~SPL
Audio Opus Opus #3 UERR Stock Balanced Balanced High 99 76.2
Aune S6 UERR Stock Balanced Balanced NA 47 76.2
FiiO X5iii UERR Stock Balanced Balanced High 65 76.2
FiiO X5iii Noble Kaiser Encore Double Helix Cables Symbiote Elite SP v3 Balanced High 47 78.2
Aune S6 Noble Kaiser Encore Double Helix Cables Symbiote Elite SP v3 to Eidolic 2.5mm to 4-pin XLR Balanced NA 42 78.2
Aune M1S (firmware 1.05A) Noble Kaiser Encore Double Helix Cables Symbiote Elite SP v3 Balanced Low 62 78.1
Echobox Explorer Noble Kaiser Encore Double Helix Cables Symbiote Elite SP v3, DHC 3.5mm adaptor SE NA ~55% 78.2


Here are some selected stats. For full stats, go to FiiO’s website. They have done a really impressive job listing stats and their methods of measurement. This is something that should be applauded. Applaud by going and having a look at their fine work here.

Price $399 (£389)
DAC Chips Dual AKM AK4490EN
System on Chip (SoC) Rockchip RK3188 Quad Core Cortex A9 processor
Amplifier Low-pass filter: OPA1612, Op-amps: customised OPA426 x 2
Output power Single-ended: ≥250 mW (32Ω /THD+N<1%)
Balanced: ≥240 mW (32Ω /THD+N<1%)
Output impedance Single-ended: <1Ω (32Ω loaded)

Balanced: <3Ω (32Ω loaded)

Recommended headphone impedance 6 – 150Ω
Total Harmonic Distortion + N (THD+N) <0.0009% (1 kHz/10kΩ, line out), <0.003% (1 kHz, headphones)
Signal to Noise Ratio 120dB (Line Out); ≥115 dB (A-weighted, SE headphones); ≥111 dB (A-weighted, balanced headphone)
Frequency Response 5 Hz~55 kHz (-3dB)
Channel Separation Single Ended (headphone): >73 dB (1 kHz)

Balanced and line-out: ≥98 dB (1 kHz)

Outputs 3.5mm headphone out, 2.5mm (balanced) headphone out, 3.5mm line-out with coaxial digital adaptor
Internal storage 32GB
Expandable storage 2 microSD slots (512GB)
Display 3.97” IPS panel (480*800)
Charge modes Quick Charge, and standard
WiFi 2.4Ghz
Bluetooth 4.0 aptX low-latency
Format support PCM 44.1-352.8kHz (16, 24, 32 bit); DSD64-DSD128 (single to double DSD; iso, dsf, and dff); APE; MP3; ALAC; AAC; OGG, WAV, WMA, AIFF, ALAC
Accessories Black leatherette case, clear TPU case, USB cable, tempered glass screen protector (installed), coaxial digital adaptor, quick-start guide
Dimensions 114.2mm (H) x 66.2mm (W) x 14.8mm (D)
Weight 187g


The FiiO X5iii sounds acceptable to good, but the DAP is more about bells and whistles than sound. When I compared the X5iii to other DAPs and DAC/Amps it invariably lost on sound quality. It doesn’t have the audio capabilities of the Aune M1s at $249 it lags far behind TheBit’s Opus #3 at $899 (I think this price will come down). It has better features than all the DAPs I compared it to, but if I was looking for features over sound I could probably just listen to my cell phone on plenty of music with plenty of headphones. The DAC chips are good in the X5iii, so if you feed it into an amp, the sound does improve, but if you were planning on using the X5iii as a transport, you’ll be disappointed in FiiO’s choice of a coaxial connection over an optical connection.

If sound is your most important criteria in an audio player, there are significantly better options available at price levels below and above the FiiO X5iii. Before doing this review I was hoping that FiiO had finally made a real giant killer. Some reviews out there made it seem that way, but my experience was different. This device is a great DAP shackled by an average amp. It is no giant killer.

5 thoughts on “FiiO X5iii: the giant killer that wasn’t

Add yours

  1. Hi. Based on your review I have a question. I want to make my Fiio X5iii more linear and less warm. I use it with a schiit Magni 3. However the amping makes the sound even more fuller and woolier. Is there a way through equalization to make the sound more linear?


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

Website Powered by

Up ↑


Enjoy music through headphones on a low budget

Headphones n' Stuff

Gear For Your Ears

Rachel's Reviews

Rottentomatoes Certified Critic. Reviews of the latest movies especially animation as well as classic reviews, family movie night picks and more

ngoshawk sounds

Portable audio reviews


Audiophile and proud

Twister6 Reviews

Twister6 Audio Gear Reviews

Audio123 Reviews

Reviews on IEM, Earbud, Cable, DAC/AMP, DAP


my story of the sounds that i hear

wauwatosa tube factory

tubes for the noobs in us all

%d bloggers like this: