FiiO M5 - Do it All DAP

This is a product review of the FiiO M5 Ultra-Portable High-Resolution Audio Player, which is available for sale now on Apos.

This review is posted here in partnership with It was originally written and published by Sandu Vitalie of on Aug. 22, 2019.


FiiO released a lot of portable devices capable of playing back music for the general public or for starry-eyed audiophiles, they even shown efforts for the wireless aficionados and released few products as well. At FiiO Spring Festival 2019 was shown a product what was positioned as a marriage between the best wireless sender/receiver and a portable audio player. I know personally some folks that adore their FiiO BTR3 but would kill to have a same kind of device but with an added player functionality. I’m glad FiiO pleased the crowd and decided to work on and release the tiny do-it-all M5.

As a product placement, FiiO put it into the player category, looking at it myself it is much more than that, it fits in the BTR Bluetooth-enabled devices as well, hell, it even has a voice recorder function, a pedometer and can be used as a rudimentary smart-watch.

Unboxing & Packaging

The box is really small and thin, nothing too fancy really, just a simple card-board box. Opening it up reveals the M5 surrounded by some shock-absorbing foam wrapped in a white material. There is also an accessory box that carries the usual paperwork (warranty information, quick start guide, open source licenses), a USB type-C cable, two screen protectors and a clear carry case. I really like that FiiO is using the exact box sizes and uses every square inch inside the box.

This is basically it; you have everything inside to start you listening session. In case you’ll want to use it at your arms wrist, FiiO is selling separately a silicon watchband for it called SK-M5.

Design & Build Quality

M5 is so small that I can’t understand how so many things were stuffed inside, it is just a bit thicker than a typical smartwatch and a bit heavier as well. Build quality is really nice considering the price bracket and size. The front and backside are covered by thick 2.5D glass, both have a screen protector pre-applied from the factory, a very nice touch from FiiO. The sides are made out of matte hard-plastic. It feels really sturdy in-hand and nicely put together. As with some recent FiiO devices I like that FiiO, Hi-Res and Hi-Res Wireless logos are underneath the glass adding class and refinement to an already nice-looking device.

As a whole it looks minimalist, the buttons have a very firm clicky sound and are not rattling at all. If you asking yourself why FiiO put glass on front and back you should understand that M5 is also positioned as a powerful Bluetooth sending or receiving device and glass will not stay in front of the wireless signal, Bluetooth antennae placement becomes less of a pain with a big glass panel.

Buttons & Layout

M5 is a touch screen enabled device so it is obvious M5 loves to be touched and swiped left and right, still it has few ports and buttons. Left and the right side are completely buttonless for a nice clean look. On top you have your headphone out/line-out/coax-out in a single 3.5mm combo jack, there are two volume buttons and a power On/Off button. On top there are also 2 dedicated microphones for the recording functionality, you can even use them in a phone call in case you hook it up to your phone via Bluetooth. On the bottom there is your microSD card slot that will accept cards up to 2Tb of memory, there is also a single USB type-C for data transfer, charging or using M5 as an external USB DAC.


The tiny touch-screen is small in size but it is easy to read due to a high brightness and decent resolution and pixel size. At 1.54” and having a 240x240 pixel resolution you are getting a 220 dots per inch for a quite crisp image. This is a square display and the whole body is square shaped as well, very Apple Watch like. The M5 is not completely bezel-less and it still has small bezels around the screen, but I’m OK with that.


M5 has a 3.7 V Li-Po battery inside with a capacity of 550 mAh. It will provide around 10 hours and a half of playtime using headphones, about 12 hours if it is working as a Bluetooth sender and about 13 hours and a half if it is working as a Bluetooth receiver. With harder to drive headphones and using higher volume setting will normally lower those numbers.

I mainly listened to it via my Quad ERA-1 headphones at home and got about 9 hours and 20 minutes on the 55-volume setting (out of maximum of 60) and I got the specified 10 hours and a half with the very efficient FiiO FA7 and IKKO OH1.

M5 will have a deep sleep for 22 days, please shut it down properly if you want to preserve battery life.

Under the Glass

Since M5 is not rocking a custom-made Android OS like its bigger brothers and it not having any Wi-Fi music streaming capabilities, it was not mandatory using a powerful processor and SoC. M5 is relying on the Ingenic X1000E CPU clocked at 1 Ghz that is also found on M3K.

M5 doesn’t an internal ROM memory and is completely relying on external MicroSD cards, the RAM memory is 64Mb in size, but it is not as important since it already moves decently and no 3-rd party apps can be installed.

At the heart of M5 music playback a new and interesting DAC chip was used, more exactly the AK4377ECB, that is a direct successor to the AK4376A found in the M3K.

What is so interesting about it you might ask? First of all, this chip decodes audio streams but also works as a headphone amplifier shorting the signal path. It has higher SNR numbers for a better dynamic range and also a lower harmonic distortion than its predecessor. 

Headphone amp duties are of course carried by the same AK4477ECB and it is offering 42mW into a 16 Ω load and 23mW of power into 32 Ω, pretty much the same power output with the M3K, BTR1K and BTR3.

FiiO used a powerful Bluetooth chip inside, it is the premium tiered CSR8675 from Qualcomm and at this moment is probably the most advanced Bluetooth chip, as a receiver M5 will decode SBC, AAC, AptX, AptX-HD and LDAC and as a transmitter M5 will send SBC, AptX and LDAC signals. The only downside is the Bluetooth version 4.2 that has a shorter beaming distance compared to BT 5.0.

It paired nicely with 3 pairs of true wireless headphones, with my TV and also with few wireless speakers. At about 10 meters distance the signal was still going pretty strong, with 2 thick walls in front of me the signal is not as strong and loses a beat or two, but using M5 in my pocket with a pair on headphones on my head worked as a charm and the signal was super stable all the time, even jogging outside.

Graphical User Interface (GUI)

In my view this is the simplest GUI I ever seen on a FiiO device; it is even simpler than that of M3K. With M5, FiiO again proved that they can certainly design a custom made (Linux-based) operating system. For the first time I didn’t need to check the quick start guide to learn all the tips and tricks.

M5 is not a multi-touch device and can be operated only by single-touches, swipes or by the 3 buttons on top.

On the home screen a single icon is shown at a time, you have the: Now Playing, Browse Files, BT receiver, Settings, Recording, Step Counter and Category, all of them are self-explanatory. 

Once you select any icon a swipe from left to right will get you back one step and pressing the home button on top will get you back to the 7 icons. In the Now Playing menu a single tap will show the cover art, where volume can be controlled as a simple swipe up or down.

Since FiiO is selling separately the SK-M5 silicone watch-band for it, M5 can be used as a simple watch with few smart capabilities, you have few nice-looking screen savers, mostly looking like an analog or digital clock.

The only thing that is a bit trickier to find is the Bluetooth transmitter as this feature is found in the settings menu.

I was pleasantly surprised to see the DAC feature implemented in such a small device; I am not crazy about it but someone will surely find this feature interesting.

The pedometer (Step counter) feature is also a nice add and positions the M5 as a hybrid smart watch as well, I am not using this feature since majority of higher-end smartphones already have a pedometer implemented but again this might be an interesting feature for someone else.

Overall the GUI is polished (FW 1.20) and moves decently fast, it stutters a bit when I am playing Hi-Res and DSD material, M3K did exactly like this as the SoC struggles a bit with multi-tasking. Using its recording feature or the Bluetooth features worked nice and quite fast. What cheered me up is that after updating to FW 1.20 I didn’t have a single error or shutdown; it just works as intended. If you will be listening mainly to lossless 16 bit files stuttering becomes less of an issue as is works snappier and faster overall.

Audio Performance

I will first start with its power output and how in general it performs with IEMs and headphones.

As crazy as it sounds M5 drove decently my Quad ERA-1 planars and more than decently a pair of Sennheiser HD660S. Volume wise I was somewhere between 55 and 60 (60 is the max volume) with the first one and between 52 and 57 with the last one. Dynamics were pretty good, I was hearing a nice kick from fast dynamics and had a good impact as well. The more I listened the more I realized it actually sounds a bit more engaging than the mobile ESS Sabre designs, can’t explain why.

Having only 2.5 uV of noise on the headphone output it actually paired very well with FiiO’s own FA7 IEMs and with sensitive IKKO OH1. I didn’t hear disturbing hum or hiss, so M5 can be easily used with IEMs. Be advised that at only 42 mW at maximum volume it will not drive with lots authority and slam a pair of multi-driver IEM, you will still need to use a more powerful device.

However, with all that said, it sounded nowhere near dead to me even with planar-magnetics. Quad Era-1 sounded more than decent with quite some punch in the low end, crispy up top and musical in the midrange. Muddiness was not spotted and it never sounded dry or soul-less, a very nice first impression indeed.

I left it playing non-stop with a charger attached to it for about 48 hours and resumed my listening session. Truth to be told it sounded nice from the start and not a lot was changed after the burn-in period ended.

I listened to some Vampire Weekend and The Last Shadow Puppets to wake-up those faster dynamic swings and M5 performed admirably in this area. A-Punk and Aviation kicked my eardrums pretty serious and was not losing control or slam. Using easier to drive headphones like the portable Sennheiser Momentum 2.0 or the Master&Dynamic MW65 (wired) was a real treat as these mid-tiered headphones were driven nicely and everything sounded good from the get-go. Sound was polished top to bottom without obvious flaws, without peaky treble or flabby bass.

What was a bit unexpected is that M5 is not sounding 2D at all and most of the time it is quite open and is enveloping my head.

Listening to Loreena McKennitt – The Gates Of Istanbul was an interesting experience, once I closed my eyes I imagined I was listening to a desktop DAC+headphone amp unit as everything was present. The music was really layered and everything would come towards me from different angles. M5 is far from 2D sounding and for its size has impressive holography and an out of head experience.

In my opinion this is the strongest point of M5 as it never crowds the performance in a single blob of sound but more like decompresses everything.

If I am switching to harder to drive headphones, of course the soundstage will shrink in size and the overall airy presentation will became flatter and not as impressive.

Moving on to the frequency response is important to note that AKM chips, even mobile ones are very capable of rendering clean bass lines and play treble in a natural fashion. M5 is no exception to that rule.

M5 rounds a bit the overall performance, so the lowest bass notes are a bit shy and the sub-sonic upper treble is splintered as well for a natural performance.

Listening to bass heavy tracks is still an engaging and a headbanging experience as Massive Attack, The Prodigy and Infected Mushroom will still sound as themselves with tons of bass notes thrown around the listener. The mid-bass will come forward more often on M5 with sub-bass put in the shade. It emphasizes the mid-bass and the midrange as well, so M5 always sounds a bit warm and invites listening to more tunes. M5 is actually never too aggressive and can be listened to for a longer period of time. A feature that lots of AKM-based DAPs are having.

M5 has smoother presentation, like the musical notes are bonded to each other, smooth and easy going most of the time. If you plan on using it for more than one hour at a time, M5 is exceptional at this and will not induce listening fatigue.

Take me for example, I am already finishing the last Tool album and my ears are still craving for more, M5 will offer fatigue-free listening experiences.

As was the case with the mid-bass, the mid tones are also a bit boosted to induce musicality, flow and naturalness. As much as I love linearity, a bit of color to the music never hurts, especially when you are just casually listening and not critically listening.

Midrange together with mid-bass are among the strongest points of M5. Voices are quite enveloping and are not hitting the rest of the performance, always floating in their own air bubbles, I would not classify them (mid-tones) as soul reaching and incredibly palpable and natural but M5 goes mostly into that direction in detriment of a super technical and sharp performance.

Finishing the 4th album from my Tool listening spree I observed that treble performance is quite sparkly and cymbals will have a nice splash and hit but with a weaker sustain as they decay faster than the rest of the performance. That was one of the reasons I could actually listen to 4 albums in a single take, Tool is not shy at using percussion with lots of treble notes and that faster decay in the upper registers made me casually listen to all that music without clenching my teeth. If you are a treble addict M5 will not please you too much, but if you hate harsh peaky treble M5 will reward you with a clear and natural treble performance. I just wish it had a little bit more information in the 15 – 19 kHz area but I guess at $109 I am already asking too much.

Going wireless with my KEF LS50W using the AptX codec was a delight as at the palm of my hands I had 128 Gb of music that I can easily control. Of course, at a distance of 2 to 3 meters the signal didn’t drop once and it left a good impression on me.

Going outside for a walk I used a pair of Master&Dynamic MW65 and with the AptX-HD codec the sound was a bit sharper and clearer than with my speakers and it was pretty close to the wired performance of MW65. The signal again stayed stable and I didn’t have a single drop in my 2-hour walk.

Creative Outlier Air and Hifiman TWS600 worked nice as well and the only issues I had was the lower sound quality because of the weaker codec support of both IEMs, M5 was not the one to blame here.

The only case when I was losing BT signal was inside the flat when between me and M5 would stay two thick concrete walls, otherwise the signal would be stable. I have nothing to complain in terms of Bluetooth capabilities.


I think it was mandatory comparing the M3K based on the older AK4476 chipset to the M5 so here we go.

M5 ($110) VS M3K ($76)

Build quality and size aside I will go directly into the audio performance. Both are sounding very alike, that is pretty clear from the first moments, but (there is always one) M5 is sounding a bit airier and more layered, not by much but it is noticeable. M5 is sounding deeper and more wide-spread whereas M3K is more up-front and closed-in to the listener.

If you listen critically to some higher mastering tracks on some higher quality headphones you can even spot an added layer of micro-detail information on the M5 that is missing on M3K, it sounds a bit cleaner and a bit more open. With detailed IEMs I again spot few small nuanced that are not as easily spotted on M3K.

In terms of power output and how clean is the HP out, both are identical, I can’t spot a difference, both have clean HP outputs and the same power as well.

I consider M5 a nice step-up from M3K if you want to hear more of everything and if you want to hear deeper into the recording.

M5 ($110) VS M6 ($160)

Another mandatory comparison is with M6 from FiiO that breathes above M5 as its bigger brother.

Again, build quality and size aside I will go directly to audio performance.

From the first listen it is clear that both were tuned a bit differently. M5 will Wow you with a layered, musical and well spread sound that is mostly smooth and relaxing, whereas M6 will impress more with its extended frequency area and with a flatter performance. M6 will have more micro-detail information, especially in the treble area, but in the same time it sounds flatter and leaner, not as engaging and a bit up-front, not very layered.

If you want more details and a flat as a ruler performance then M6 is that device, if you want an engaging performance with zero listening fatigue M5 would be that device. When it comes to power output, M6 is easily outperforming M5 and will offer a better driver control, a better slam and impact into the ear-drums.

Both are sounding good but carry a different tuning. M6 wins in terms of power and streaming capabilities, it is just more advanced but more expensive as well.

In terms of audio performance both are almost on the same level with a different approach to music playback.


So here you have it guys, M5 is a powerful Bluetooth transmitter and receiver with a wide BT codec support. It sounds clean, quite detailed and layered as a player. GUI is quite polished and easy to navigate and remember where everything is placed in the menu.

At this size it is the smallest current production DAP from FiiO, portability factor is crazy good and this is what I call a really portable digital-audio-player.

Probably the best part of everything is its price, at only $109.99 there is nothing to complain about, it feels good in hand, moves decent, performs admirably and offers a lot in exchange of a small price to pay. Overall, M5 offers an impressive price to performance ratio that will be really hard to beat in the future.

You can get it from here (Apos is offering free shipping in the USA, free 30-day returns in case you don’t like it, an extra 1 year of warranty and lowest price guarantee).


  • Cute design, small, lightweight and portable
  • Natural sound signature without sounding boring
  • Great balance between technical and musical
  • Wide airy stage, deep sounding as well
  • Great Bluetooth codec support
  • Works as both a sender and a Bluetooth receiver
  • Decent detail retrieval, sounds clean as well
  • Noise-less HP out
  • Impressive price to performance ratio


  • No Bluetooth 5.0
  • Limited power output for bigger headphones
  • Rounded audio performance (small roll-off in the sub-bass and upper treble)


  • Sources: Xiaomi Mi Mix 2S, Alienware Aurora R7, Sony Bravia 65XE9005
  • DACs: Matrix Audio Element X, KECES S3, Burson Swing, FiiO Q5S
  • DAPs: FiiO M5, M6, M3K
  • Headphone amps: Benchmark HPA4, Aune S7 PRO, Erzetich Bacillus, Headamp Gilmore Lite Mk2
  • IEMs: FiiO FA7, IKKO OH1
  • True Wireless headphones: Creative Outlier Air, Hifiman TWS600
  • Full-sized headphones: Hifiman Arya, Quad ERA-1, Sennheiser HD660S
  • Wireless headphones: Master&Dynamic MW65
  • Loudspeakers: KEF LS50W
  • Interconnects: QED Reference XLR, Aune AL3 XLR
  • Power Cables: Isotek EVO3 Premier
  • Balanced Power Conditioners: PLiXiR Elite BAC 400, KECES BP-600