FiiO M17 Portable High-Resolution Audio Player review

New and innovative “head-fi” devices seem to be hitting the market at a dizzying rate these days, each with with ever-increasing capabilities and specifications to tempt the eyes and ears of headphone enthusiasts. However, nothing in recent memory has been quite so stupendously jam-packed with features, power, and potential applications as the new category-defying FiiO M17 Portable High-Resolution Audio Player, which is available now from Addicted To Audio for $2689.  

Desktop power and capabilities, on-the-go

Let’s get one thing out of the way early - the new FiiO M17 Portable High-Resolution Audio Player is a beast. I’d seen pictures of it ahead of getting my hands on a review unit, but I wasn’t quite ready for just how monstrous it was until I felt the sheer heft of all 610 grams’-worth of Digital Audio Player (a.k.a “DAP”) in my hand. In fact, it almost feels a little comical to call the M17 merely a “DAP”. Why? Well, firstly, that acronym conjures up visions of a small music player that you slip in your pocket while you’re out and about enjoying a few tunes…and unless you’re wearing clown pants, the M17 ain’t exactly what I’d call “pocketable”. 

Next, FiiO has engineered the M17 with the kinds of amplification, DAC-chips and User Interface capabilities that will put many desktop-grade devices to shame. And unlike many portable-only devices, the M17 boasts a huge array of input and output options that make it ready to work at the heart of an integrated desktop digital or analogue audio chain. The M17 has four separate headphone outputs, including 2.5mm and 4.4mm balanced connections, a standard 3.5mm single-ended output, and somewhat unusually for a mobile-capable device - a full-sized 6.3mm headphone jack. 

Two USB-c connections on the bottom of the M17 enable charging and data transfer and USB “host mode” respectively - the latter allows the M17 to work as an external USB DAC, or conversely to use the M17 as a digital source with a separate DAC. An RCA coaxial connection is also housed on the bottom of the device which can be used as either an input, say for example with a CD player or transport, or as an output to an external jack. So in other words, this is one seriously versatile little portable device. 

A portable powerhouse

Being almost as big as a small paperback novel, you’d expect the M17 to pack a bit more of a punch than your garden-variety DAP, and you wouldn’t be wrong. FiiO worked with legendary audio company THX to develop the THX AAA-788+ amplification chip (which is exclusive to the M17), and one of these has been used in each channel to give the M17 a mind-boggling 3 Watts power to provide enough juice for even the most stubborn, hard-to-drive cans. Hang on, doesn’t “THX” sound a bit familiar? Yes, it’s “that” THX - the audio subsidiary of Lucasfilm, founded back in 1983 by George Lucas, that provides quality assurance for digital audio standards. So, if you plonk an M17 down on the table in front of your mates (carefully…you might squash something) you can brag that it has a bit of “Star Wars DNA” inside. 

The M17 is powered by a whopping 9,200mAh battery that offers up to ten hours of playback when using single-ended headphones, or around eight and a half when using one of the two balanced outputs. As well as being able to be charged via USB, the M17 also has a completely separate external DC power supply. When the (included) external DC power cord is connected the battery is bypassed completely and the M17’s voltage is increased by some 35%. A 430mF DMF super-capacitor also sits underneath the M17’s (rather substantial!) hood to ensure a constant stream of on-demand power when musical peaks require a steady delivery of voltage. 

While the sheer amount of power might seem a little “scary” for headphone use, the M17 has four switchable gain modes which make it a great match for pairing with sensitive IEMs and power-hungry planar magnetic headphones alike. The gain levels for each setting are as follows:

  • Low: -6dB
  • Medium: 0dB
  • High Gain: 6dB
  • Over-ear headphone mode: 13dB
  • Enhanced over-ear headphone mode: 16dB

While I said that the M17 has four gain modes, that last mode mentioned - “Enhanced Over-Ear Headphone Mode” is a bit like a “secret” mode that can be unlocked when the M17 is plugged into its DC power supply (it does feel a bit like you’ve made an achievement in a video game when the notification pops up on the screen!), and will be your go-to mode if you plan on using some difficult headphone loads while sitting down comfortably near a power-point. 

Reference-grade wired + wireless capabilities 

Housed on a completely separate board to avoid interference with the amplification modules, the M17 uses two ES9038PRO DAC chips (one each for the left and right channels) - the flagship DAC chip from ESS, which can decode PCM up to 32-bit/768kHz, DSD512 as well as being fully MQA compatible. 

The M17 also boasts Qualcomm’s flagship QCC5124 Bluetooth chip, which allows the M17 to act as both a Bluetooth receiver and transmitter. When sending a Bluetooth signal to the M17 in “receiver” mode, the Bluetooth 5.0-capable M17 is capable of decoding practically all standard and higher-res codecs, including SBC, AAC, aptX, aptX-LL, aptX-HD, aptX Adaptive, and LDAC. If you want to use the M17 as a Bluetooth source, say for example with a pair of wireless headphones, the SBC, AAC, aptX, aptX-HD and LDAC codecs are supported. 

FiiO M17 key device specifications


Qualcomm Snapdragon 660


ES9038PRO x2


THX AAA-788+

Bluetooth Decoding


USB Decoding


Crystal Oscillator

NDK Femtosecond Crystal Oscillator x2

Working Mode

Android mode/pure tone mode/USB DAC Mode/Bluetooth Receiving Mode/AirPlay Mode/Coaxial Decoding Mode

Product Size

156.4 x 88.5 x 28mm




5.99 inches (1080*2160) incell full-fit screen


Support QC3.0, QC4.0, PD2.0 and PD3.0 fast charging Battery

Battery Capacity


Battery Life

about 10 hours (single-ended)

about 8.5 hours (balanced)

Charge Time

about 4.5h (QC fast charge)

Standby Time


Volume Control

Potentiometer Knob or Button Control




64GB/about 46GB Memory Card

Expansion Card

Maximum theoretical support 2TB

Gain Selection

Low/Medium/High/Large Ear Mode/Super Large Ear Mode (when connected to DC)

Channel Balance

L20-R20 (0.5dB per stage)

Recommended Headphone Impedance

16-150Q (single-ended output)

16-300Q (balanced output)

FiiO M17 Build and form-factor 

Have I mentioned already that the M17 is kinda big? But seriously, it’s one massive unit. Despite weighing 610 grams, having a 6-inch screen corner-to-corner, and being a full inch thick, the M17 isn’t really all that unwieldy. Sure, you’re not going to take it with you on a jog (...but then again it could be a good way to build-up arm strength) but it’ll easily fit into a bag or briefcase so that you can take V8-like headphone power with you wherever you happen to be going. 

The M17’s build quality feels both substantial and first-rate. The four edges of the main body are made from a durable, nice-to-touch plastic that surrounds a 151g all-aluminium chassis which is specially designed to dissipate heat. The rear of the M17 sports a very cool-looking reflective fractal design underneath a clear plastic cover. 

The front of the M17 is dominated by an enormous 6-inch HD display with 2160 x 1080 resolution - and it’s absolutely gorgeous. Being roughly the size of your average smartphone’s display, it’s good enough for watching HD Youtube videos (more on this later) as well as displaying your favourite albums’ cover art in all their glory. And since it’s so big, you can actually type things onto the on-screen keyboard properly without succumbing to “fat thumbs” syndrome!

The M17’s side panels host a number of buttons for controlling the M17’s key playback and control functions. These add to the M17’s “gamer”-like aesthetic, which is further enhanced by the glowing RGB lights that emanate from four slits on each side of the device, as well as from beneath the top-mounted volume wheel. The lights slowly “breathe” lighter and darker, and change colours depending on the M17’s function, music bit rate, or even device temperature. In fact, you can actually program the brightness and colour to tailor it to your favourite “RGB” vibe. Overall, the M17 has a pretty high-tech and “tough” kinda look to it that’s a little more masculine and “look at me” than the minimal/streamlined look that most manufacturers are going for these days - you know those Caterpillar industrial “CAT” phone cases? That’s the vibe I’m getting. 

Familiar play/pause + track forward/background buttons are included on the M17’s left-hand side, plus a “spare button” (that can be programmed with the go-to function of your choice) and a slider that locks the touch-screen. Over on the right-hand side of the M17, we have a power button for turning it on/off place waking and locking the screen, as well as volume up/down buttons (which can be used if you prefer them over the M17’s volume wheel). And lastly, we have a slider that allows you to alternate between battery and “DC” modes (and thereby unlock the enhanced headphone mode). 

The M17’s “roof” is chock-a-block with the four headphone jacks mentioned previously. It does feel a little peculiar to be able to plug a full-sized headphone jack into a portable device, but then again, the M17 is not exactly a shrinking violet. If you don’t feel like opting to use the up/down volume buttons, the M17 has a large volume wheel on its top panel for managing volume. It does ramp up and down pretty quickly between the 120 increments of volume in my experience and isn’t quite as accurate as using the buttons, but if you need to quickly dial back those 3 Watts of power in a hurry it is helpful if you’ve plugged in a pair of IEMs and forgot to change the output level. 

Being a portable (ish) device, FiiO has kindly included an excellent leather protective case befitting their flagship digital audio player, complete with a skeletonised metal grille on the rear to help with airflow and cooling. It makes finding the right button a little trickier when you’re not looking at what you’re doing, but I suspect most owners will keep it on at all times as the brown leather design looks good, and it’ll prevent scratching and bumps on your sizeable portable investment when moving the M17 around.  

Unboxing the FiiO M17

FiiO has appropriately included all the bells and whistles befitting a premium, flagship device with their M17, including:

  • External DC charging adapter
  • Cooling stand with fan
  • Clear screen protector
  • Leather case
  • Micro-DS card ejector pin
  • USB 3.0 data and power cable
  • Aluminium dust plugs for the 6.3mm/4.4mm jack and DC input 

Cooling desktop cradle

Seeing as FiiO has designed and marketed the M17 as a desktop-capable device, they’ve thoughtfully included a desktop cradle device which has been specially designed to be mated with the M17. Made from black powder-coated metal, it’s nice and sturdy and definitely keeps the plus-sized M17 nice and stable, as well as making it easily accessible while you have it in front of you on your desktop. The M17’s stand also helps with cable management thanks to a handy cutout on the lower part that the bottom of the device sits on to let you plug in your DC, USB or coaxial cables.  

The interesting part about the M17’s stand is that it has a built-in USB-powered fan - with so much power on tap, FiiO has gone to great lengths to ensure proper thermal management with the M17 to prevent it from overheating. Even when used in DC/Enhanced Headphone Mode with the (very demanding) HiFiman Susvara, I never really found that it got hot enough to warrant switching it on - it has two speeds and it’s definitely audible when switched on (particularly in the “high” mode), so I preferred to keep it off. If you’re using it for hours on end and live in a hotter climate, then you may want to make use of it. 

User experience and operating system

The M17 is the closest I’ve come to experiencing a proper Smartphone-like experience on a digital audio player. Rocking a near-stock Android 10 operating system powered by an 8-core Snapdragon 660 chipset, the M17 is an absolute joy to use. As an Android user myself, the UI was immediately familiar, plus you get all the customisation and power of the Android system to tailor your experience. Using the Google Play store, I had Qobuz and Youtube installed within minutes, and next, I customised the home-screen interface with my preferred “three-button” configuration to manage “back”, “home”, and “app minimising”. You can even set the screen to auto-rotate depending on how you’re holding it - just like on an Android phone.

The display is snappy and responsive, and swiping between playlists and apps on that stunning 6-inch display works seamlessly. It seems that there are some limitations to the Android operating system used by FiiO, as I wasn’t able to install Netflix, and Stan couldn’t manage to playback videos. However, Youtube works absolutely seamlessly on the M17 and it’s a terrific device to watch videos on (with great sound, naturally) so long as you can find a comfortable way to hold or place it. 

The M17’s dual-band wifi performance was reassuringly strong, and if you’re a streaming-service subscriber you might never want to leave the comfort of your music streaming app of choice. The M17’s 64Gb of onboard storage plus the ability to have another terabyte or so’s worth of space using a MicroSD card means that you can download album after album, and playlist after playlist. This also means that you can store an entire library of high-res files onto the M17 and play them by using the excellent FiiO Music app. The proprietary app from FiiO works brilliantly for local file playback, quickly scanning and sorting the 500Gb or so’s worth of FLAC files that I loaded onto it and sorting them into their respective categories along with their cover art. Building playlists and scanning through artists, songs and albums is relatively straightforward, and it also includes the ability to connect to any music servers housed on a local network. 

The FiiO music app also includes a pretty useful equalisation tool if you want to have a tinker with the sound to suit your headphones and IEMs, and while I’m not a big EQ user I have no complaints here. One very cool touch is the optional VU-meter display that you can have on-screen while listening via the FiiO Music app - I’m an absolute sucker for a VU-meter so this is a nice touch in my books. 


If you feel like being a bit less “offline” and eschewing all the connectivity that comes with streaming and wifi, you can choose to make the M17 a bit more “old school” and use it as a pure digital audio player by switching it into “Pure Music Mode”. This takes you out of the Android interface and straight into the FiiO Music player app, meaning that you can simply enjoy your local music library without any interference from the outside world, or the temptation to “skip” onto something new. 

And that’s not the only “mode” you can use the M17 with - there are four more! “USB DAC” mode turns the M17 into a pure DAC/amp device that you can connect to your laptop or phone; “Bluetooth Receiving Mode” does the same thing, except that it accepts a wireless signal from an external source; “SPDIF RX” works just like the USB DAC mode, however it uses an external coaxial source; and “Airplay” mode does exactly what you think it does - it receives an audio signal from Apple devices on the same network. I tested each mode and they all work exactly as advertised - with the M17 parked on my desk while I was working I had it connected to both my Macbook and Roon library as well as my CD player via the coaxial connection, and it worked brilliantly as a digital hub - switching between modes and sources is a piece of cake. 

Seeing as you have a pretty capable DAC and source device on your hands, you can also use the M17 as a standalone DAC or preamp. You can switch it into “line out” mode using either the 4.4mm balanced or 3.5mm headphone jacks and feed the signal into a downstream amplifier or preamplifier. I also had the M17 perform pre-amp duties, using its variable volume control upstream of a power amplifier and passive speakers in my office, and it worked brilliantly in this configuration. I tended to keep the M17 in “Enhanced Headphone Mode” while desk-bound, meaning I wasn’t drawing power from its battery. While I haven’t really done any travel of note in the last few weeks (aside from the odd run to the shops here and there), when switching over to battery mode I did experience a battery drain of about 10% an hour - pretty much bang-on as advertised. 

There is a lot to take in when you first switch on the M17 and figure out how to start using it. I’m not saying that because it’s a complicated device - in fact, it’s pretty intuitive to use - but there are simply so many features on-tap that you need to spend a day or so exploring the different buttons, settings, and menus to figure out exactly how to access them all. It’s not exactly what I’d call a device for the “minimalist” - in fact, it’s quite the opposite. If you want absolute control over every aspect of your headphone listening and the ability to tailor and customise your experience while using it in almost any conceivable listening application, then the M17 will very much be your cup of tea. 

Using the M17 as a stationary desktop device isn’t as cumbersome as I thought it might have been. While you do have to be a little careful with all the cables that will be sticking out of the top and bottom of the device, the M17’s weight means that it stays firmly put in its cradle, and when it’s in arm’s length its a cinch to change volume and manage key functions either through the screen interface, or the physical controls on the device. Sure, it’s not quite so elegant as a well-designed and implemented desktop device, but the fact that you can pick it up and take it with you more than makes up for this.  

With its terrific operating system and a generous smattering of inputs and outputs (not to mention its stupendous headphone driving potential), the M17 feels not only future-ready but future-proof. It’s only really missing two things in my books that would make it absolutely perfect for my needs - an optical connection for easy pairing with a Smart TV or gaming console, and “Roon Ready” certification - here’s hoping the latter might come down the track with a future firmware upgrade. 

Listening to the FiiO M17

I figured it was probably best to start out small, and then gradually ramp things up in terms of power when it came to testing how the M17 boogies with headphones and IEMs. I decided to start off in “low” gain with the 64 Audio Duo Universal In-Ear Earphones, which I’ve come to appreciate even more since I reviewed them earlier this year (read my 64 Audio Duo Universal In-Ear Earphones review for more on these!). Listening to a 24-bit/4.1kHz FLAC copy of Polygondwanaland from none other than Melbourne’s King Gizzard and the Lizard Wizard, I was immediately impressed by the complete absence of any noise floor whatsoever when I plugged in the Duos. Gradually twisting up the volume wheel to around 47/120, the M17/Duo pairing then proceeded to paint an impressively wide and immersive picture, creating a terrific sense of air and separation between the different instrument and vocal tracks. There was an absolute ton of detail on vivid display in the title track (#2 on the album), but also a nice sweetness to balance out the sound with a nice dense mid-bass and textured mid-range so there’s no hint of digital starkness whatsoever. The M17’s tone is thoroughly enjoyable, and at this stage it’s proving to have terrific technical abilities - the placement, attack and decay of drum hits and acoustic guitar plucks that I was hearing the 64 Audio Duo were just perfect. 

For good measure, I spent some time testing the new Campfire Audio Supermoon Custom In Ear Monitors with the M17 to check that it wasn’t just a one-off IEM eureka moment. The Supermoon is a very different sounding IEM to the Duo - it uses Campfire’s newly developed planar magnetic driver, and has a much leaner, snappier presentation that’s focused more on speed and accuracy compared to the more relaxed, euphonic Duo. An enjoyable listen through the 24-bit/44.1kHz Qobuz version of Run the Jewels 3 proved that the M17 had the nuance to keep up with the blindingly-fast Supermoon, and rounded out their leaner voicing with simply awesome bass that was laser-focused and didn’t leave behind any trailing edges or give any sense of “bloat” whatsoever” - just sheer dynamic impact and pleasure. 

Next, it was time to see how the M17 fares when it comes to powering full-sized, hard-to-drive cans. I didn’t want to muck around so went straight to “Enhanced” mode to unleash the M17’s full 3 Watts of power. The Sennheiser HD800s Audiophile Headphones might have 300-ohm drivers but they aren’t a particularly difficult amplifier load thanks to their 102dB sensitivity - they only needed between 35-40/120 on the M17’s most powerful setting to get up to full volume when connected to the 4.4mm balanced jack. The HD800s can sound a little flat and almost telephonic when paired with a less than impressive amplifier, but the M17 drove it with outright gusto when I fired up a 24-bit/96kHz FLAC rip of Queens of the Stone Age’s Villains album. This Mark Ronson-produced record rocks with the HD800s/M17 combo - the bass and kick drums in Feet Don’t Fail Me slam with genuine impact, and you feel every lick of the snarling electric guitars - my feet certainly didn’t fail to get tapping! The M17 also does the HD800s’ stellar soundstage and imaging capabilities full justice, creating a fully “visible” canvas with genuine front-to-back depth as well as placing individual tracks left to right over a properly diffuse stage. 

Taking things up another level in terms of being a difficult load for an amplifier load, I next paired the M17 the Audeze LCD-5 Reference Planar Magnetic Open Back Headphones, which are give an astonishingly detailed and revealing look into your source gear and demand an excellent upstream DAC and amplifier. With a sensitivity rating of 90dB they require a trifle more power to reach the same sound pressure level as the HD800s, and yet the M17 didn’t need to go beyond 45/120 running the LCD-5 from the 6.3mm single-ended jack before Atoms For Peace’s AMOK started to get a little too loud - although it sounded so bloody good I was a little tempted to give the wheel a bit more of a nudge... 

AMOK features Radiohead’s Thom Yorke on vocals, Red Hot Chilli Pepper’s Flea on bass, and is produced by long-term Radiohead contributor Nigel Godrich. It’s a brilliantly-created mish-mash of soundscapes, fast-paced and constantly changing rhythms, and low-key melodies - and it’s also a great test of how well a device can manage intricate transients, deliver abrupt dynamic swings, and place sudden electronic noises into a believable “stage” around your head. The M17 acquitted itself absolutely brilliantly on all accounts with the LCD-5 and more than stepped up to the mark. I spent some time doing some A/B testing it against a very expensive and very powerful class-A pure headphone amplifier that I have on my desktop for testing, and surprisingly, the M17 really didn’t leave much on the table. The electronic “dripping tap” effect coming from the right channel in the track Ingenue did feel a bit closer and less ethereal-sounding on the M17 than it did on the reference amp on my desktop (if I’m being picky), and there was nominally less dynamic impact from the ear-tickling, staccato-like percussion on the FiiO, but holy moly - this kind of performance from a battery-powered, portable device? Incredible. 

And for my final “torture-test”? Well, it was time for none other than the HIFIMAN Susvara Planar Magnetic Driver Headphones. Yes that Susvara - the headphone with a crazily-low 83dB sensitivity rating that people swear can only be awoken with it strapped to the speaker terminals of a power amplifier and an appropriate animal sacrifice made to the headphones. With David Bowie’s 26th and final album, 2016’s Blackstar streaming at 24-bit/96kHz via Qobuz, the M17 gave a full-blooded and thoroughly dynamic performance with the volume set at precisely half - that is, 60/120. The HIFIMAN flagship open back headphone sounded pretty damn convincing and entirely enjoyable when connected powered by the M17’s 6.3mm single-ended output - its absolutely linear and faultless bass didn’t quite have the same surefooted-ness and impact, and the sense of upper treble air felt a hair more compressed and stuffier compared to a reference-grade desktop amp, but the M17 served-up detail, texture and sheer enjoyability in spades. 

Final thoughts

The FiiO M17 is, put simply, the most comprehensive and capable portable device available for headphone users at the time of writing. One might think that a device so powerful and industrial-looking might take somewhat of a “sledgehammer” approach to delivering sound, but that’s simply not the case - the M17 sounds finessed and wonderfully detailed with IEMs, and will then turn around and be stonkingly powerful and authoritative with the most difficult-to-drive headphones imaginable. 

To top it all off, FiiO has designed the M17 with a terrific interface with intuitive and comprehensive functionality, and the sorts of inputs and outputs that put far larger desktop devices to shame. If you’re looking for an “all-rounder” DAC + amp combo that also happens to be a DAP, you’d be crazy not to give this one an audition.

Daps (digital audio players)Desktop headphone amps and dacsFiio