Link to my review and measurement index thread where one can also find a full review overview, more information about myself as well as my general-ish audio and review manifesto:
https://www.head-fi.org/threads/956208/
I only give full stars. My ranking/scoring system does not necessarily follow the norm and is about as follows:
5 stars: The product is
very good and received the "
highly recommended" award from me.
4 stars: The product is
very good and received the "
recommended" award from me.
3 stars: The product is
good/very good, but not outstanding/special enough to get any of my two awards. ["Thumbs Up"]
2 stars: The product is
only about average or even somewhat below that and
somewhat flawed/flawed in some areas. [neither "Thumbs Up" nor "Thumbs Down"]
1 star: The product is
bad/severely flawed to
outright bad. ["Thumbs Down"]
FiiO M5
Source:
Review sample.
Miscellaneous:
Tested at firmware version FW 1.2.0.
Plenty of wired and wireless features (aptX Bluetooth reception and transmission, USB DAC in and out), but I will mainly focus on its performance as a traditional digital audio player in my review.
No screen protector applied by factory, which is not very FiiO-like. Two protectors and a data/charging cable are included, though, along with a plastic case with integrated clip.
Available in multiple colours.
Rear made of glass.
Decent build quality.
Fairly small and compact – not as slim as my Apple iPod Nano 6G, but still nicely compact.
Surprisingly heavy for the size.
Nice blue LED above the screen (for Bluetooth-related stuff).
Rather small buttons, however easy to find and distinguish. No volume up/down (+/-) indicator except for a tactile dot on the volume up button.
Combined headphone, line and coaxial output socket.
USB-C (USB 2.0).
It’s nice that a clear plastic case with built-in shirt clip is included.
Unfortunately no built-in FM radio.
Does not seem to support in-line cable remote control commands.
Built-in microphones (can be used for hands-free phone calls when the player is connected to a mobile phone via Bluetooth) and built-in voice recorder.
Built-in step counter.
No internal storage.
Micro-SD card slot.
1.54 inch 240 x 240 pixels touchscreen (similar screen dimensions and resolution as my Apple iPod Nano 6G). Easy to read and doesn’t feel pixelated at all despite the seemingly low resolution.
The screen orientation can be changed, however, unlike on my Apple iPod Nano 6G, only through the settings and not through intuitive two-finger turns.
What's somewhat annoying: the 3.5 mm socket is located right next to the volume control buttons, wherefore operating them while a headphone/in-ear with an angled plug is inserted is only possible when the plug is turned into the other direction. The same goes for thick plugs. That's definitely better executed on my Apple iPod Nano 6G where the 3.5 mm socket and control buttons are located on opposite sides.
Graphical User Interface:
Surprisingly intuitive navigation by swipe gestures – a lot like on my Apple iPod Nano 6G, but not entirely similar (e.g. no long press return to home screen). One can go back by swiping from left to right – just like on my iPod Nano 6G.
Swiping from top to bottom and then clicking on the album cover/title/interpret display jumps straight to the playback screen where one can swipe left and right to access different playback-related screens.
Smooth and fluent navigation and animations.
Navigation (clicking on specific elements and swiping from left to right to go back) not always as precise as on my Apple iPod Nano 6G or 7G, however good most of the time.
Currently, some playback-related bugs (long track title texts aren’t fully displayed and don’t scroll automatically/cannot be scrolled horizontally by swiping over them) still persist.
Currently no volume indicator on the lock screen or playback screen or drop-down playback screen (only in the menus); only pops up when changing the volume.
Typical FiiO feature (that I also already know from my X3): “Resume mode”: “Position” leads to the playback to continue right after the player is turned on again, and there is no option to having to click on “play” manually (that’s what I like about the Rockbox firmware that I installed on my SanDisk Sansa Clip Plus, Sansa Clip Zip and the xDuoo X3 – it leaves the user the option to continue the playback automatically after booting the player or to having to click on “play” manually in order for the playback to start).
Sound:
I’m only using and testing the 3.5 mm headphone output (playback from micro-SD card).
When high sensitivity, low impedance in-ears are used, very often, there is some mild left channel crackle/pop when pausing/skipping/changing the playback position of most files and during the transition of two files (the latter mainly happens with lossy files, however the rest unfortunately also appears in almost all cases when playing lossless files (click/pop/crackle is always present when changing the playback position or when pausing/resuming the playback/muting/unmuting the volume regardless of whether the file is lossy or lossless)), and it can even happen in a silent passage of a song; so it seems as if some sort of totally unnecessary noise gate that immediately turns off the amplifier section when no signal is detected were implemented, and this is definitely highly annoying.
Gapless Playback:
Works perfectly when using FLAC files.
Volume Control:
60 volume steps (no gain setting). Gentle fading up/down when changing the volume (therefore no instant volume changes), which is definitely a matter of taste (it is definitely somewhat irritating as it takes around one second for the volume to change after pressing any of the two volume buttons).
Even using extremely sensitive in-ears such as my Campfire Audio Andromeda and playing loudly mastered files, the lowest possible volume setting above mute is quiet enough for me for quiet listening, which is very, very nice.
Personally, I wouldn't mind more steps than 60 in order to achieving finer volume step changes (that’s my general criticism about every device that doesn't have 1 dB to 0.5 dB changes per step over the entire adjustable range), but the jumps aren’t too big even in the low adjustable range, so it’s ultimately fine.
Hiss Performance:
Using my extremely sensitive Campfire Audio Andromeda, the audible hiss in a very quiet but not yet silent passage of a song is only slightly audible in a quiet room, which makes the M5 very good/almost perfectly perfect in this regard. Therefore it is one of those very rare low output impedance devices with very good hiss performance when using extremely sensitive in-ears.
Frequency Response (no Load):

FR unloaded
Unsurprisingly as flat as it is supposed to be.
Output Impedance (Ultimate Ears Triple.Fi 10 as Load):

FR loaded – Ultimate Ears Triple.Fi 10
The very small deviation indicates that FiiO’s stated specs of a very low output impedance of below 0.5 Ohms are true, and that the actual output impedance is even closer to 0 Ohms, which is perfect.
Subjective Listening Impressions:
Not all that surprisingly thanks to its good specs and measured performance, the subjectively perceived sound is very clean and transparent, “precise”, just as it should be.
Subjectively, using well-resolving multi-BA in-ears, I have the slight subjective feeling that the bass response
may be a little softer when compared to other devices such as my RME ADI-2 DAC or iBasso DX90 (as well as the iBasso DX200, DX220 and Cowon Plenue 2), but even if it were the case, it would be just one of those minor and practically irrelevant differences even in concentrated listening real-world scenarios.
While the M5’s near-perfect hiss performance and perfectly low output impedance make it theoretically perfect for extremely sensitive multi-BA in-ears, the noise gate and crackle/pops in the left channel when used with super sensitive in-ears, as described further above, are super annoying.
- - - - - - - - - - - -
Comparisons:
Apple iPod Nano 6G:
My iPod is much flatter and lighter.
Similar screen dimensions and resolution.
Both can be attached to one’s clothes using a clip. The FiiO’s is however removable.
While the FiiO comes reasonably close, the iPod is ultimately superior when it comes to navigation, responsiveness, ease of use and intuitive touchscreen control.
The iPod has got built-in memory that is not expandable whereas it’s the other way around on the FiiO.
In-line remote control commands are supported by the iPod whereas they are not by the FiiO.
The FiiO obviously offers many more features. Unlike the iPod, it lacks an FM radio, though.
In terms of output impedance, hiss performance with super sensitive in-ears and number of volume steps, the FiiO outperforms the iPod. However, the iPod lacks that noise gate and disappointing noise in the left channel that occurs under specific conditions when the FiiO is used with very sensitive in-ears.
Conclusion:
Theoretically very good nearing perfection when it comes to audio performance (especially in regards to its perfectly low output impedance and nearly perfect hiss performance), but with some highly annoying flaws when using in-ears with really high sensitivity.
Photos:
