FiiO M3K – Review

FiiO M3K

FiiO M3K

| Music Player | USB DAC | OTG | Touch Controls | IPS 2” | DSD64 |

FiiO M3K a super affordable, Hi-Res Audio certified DAP/DAC with advanced features.

The FiiO M3K features a AK4376A DAC, Ingenic X1000/E (40nm) CPU running at 1GHz, DSD64 and support for up to 384kHz/32-bit audio – beneath the clean design the device is running Linux.

FiiO is a relatively young company that has smashed the market with highly spec’ed and well-performing DAPs, DACs, Amps and headphones but with budget-friendly prices.

Since their introduction, many products from the company made them gain a solid reputation and wide fame among audio enthusiasts, some of their most acclaimed products include the:

If you are new to audio players you might be wondering what DAC and DAP mean; DAC stands for Digital-to-Analog Converter and DAP refers to Digital Audio Player.

You can buy the FiiO M3K in:

  • FiiO M3K silver
  • FiiO M3K blue (possible new color, not released nor confirmed yet)
  • FiiO M3K red (possible new color, not released nor confirmed yet)
  • FiiO M3K black (possible new color, not released nor confirmed yet)

Other of the latest products from FiiO include the:

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FiiO M3K Review

Tests & Scores


Advanced Features

The FiiO M3K features include advanced options such as:

  • Asynchronous USB DAC: can be connected as an USB external DAC, Windows and Mac compatible (driverless with Mac) – with up to 192kHz/24 bit audio
  • Audio Recording
  • USB OTG file transferring: transfer files between USB OTG-compatible devices and the FiiO M3K – works with Android smartphones
  • AB repeat: special feature to compare 2 tracks by repeating them with an A vs B comparative listening. Note: Be sure to set the multifunction button to “Repeat” (“System settings” menu), if set to “Playback control” the AB repeat function will not be accessible
  • Micro SD card slot: up to 2048GB (2TB) SDCX, SDSD, SDHC cards
  • DSD64
  • Backlit touch controls/buttons
  • Gapless playback
  • Balance
  • Maximum volume manual limit



FiiO M3K weight in Ounces and FiiO M3K weight in grams.

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Accessories & Packaging

The FiiO M3K unboxing results in a rubberized protective cover, a charging micro USB cable and a screen protector that is already placed on the screen of the unit.

The DAP/DAC comes inside a relatively small package with a clean design.




The FiiO M3K has a seamless unibody construction with a design/style inspiration coming from the popular FiiO X1 2nd generation, offering rounded edges and clean, stylish aesthetics.

With dimensions of 90.8mm×44.2mm×12mm, the FiiO M3K is a DAP/DAC with minuscule size.


FiiO M3K with Meze 99 Classics
FiiO M3K with Meze 99 Classics


Operation & Control

The FiiO M3K has four physical buttons that are found on the left edge of the device and 4 touch sensitive buttons placed on the front + a touch slider with sliding gestures that also acts as a confirmation button.

These touch buttons make use of capacitive technology, are very well implemented with an intuitive and responsive operation, while the touch pad slider adds a smooth touch scrolling and user interface navigation. Moreover, the capacitive buttons are backlit, which makes the FiiO M3K very easy to use on low-light conditions. The overall user experience was very fluid with only sporadic, minor lag while quickly navigating through long tracks/file lists.

The physical buttons can fully control the music playing main options such as: play, pause, volume up, volume down, next songs, previous song, display on, display off/lock screen. Having access to all the main controls with their physical buttons add up to their ease of use and friendly daily usage.

The screen can be locked with a dedicated physical button to avoid any accidental press of their capacitive buttons. Still with the screen locked/turned off, the unit can be completely operated with the physical buttons.


FiiO M3K buttons
FiiO M3K buttons
FiiO M3K buttons
FiiO M3K buttons


Battery Life

The FiiO M3K holds a 1100mAh lithium-polymer rechargeable battery that grants 24 to 26 hours of continuous playback time on a single charge and whopping 38 days of standby time.

How to charge the FiiO M3K:

To charge the FiiO M3K you have to plug the included charging cable to the micro USB port found on the bottom of the unit – a full charge should take approximately 2.5 hours.

FiiO recommends to charge the unit using an USB adapter with a power output of 5V 2A.


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FiiO M3K buttons
FiiO M3K buttons


Construction & Build

The FiiO M3K has a body build entirely in aluminum and a screen with rugged tempered glass to avoid scratches and shattering – additionally, the screen comes with a replaceable screen protector on top.

Overall, the unit feels very well constructed with a solid but light and small footprint.


FiiO M3K with cover
FiiO M3K with cover



The FiiO M3K has an IPS screen with a diagonal size of 2.0 inches with 262,000 colors, a resolution of 320×240 and a pixel density of 200 PPI – this amount of PPI is more than twice of what you can find in a 48” 4K TV and nearly 40% more PPI than a 32” 4K PC Monitor has.

By using an IPS screen, the angle of vision of the FiiO M3K’s screen is extremely wide and shows no “negativization” of colors – the screen brightness can be manually set in 10 different levels.


FiiO M3K
FiiO M3K



The user interface of the FiiO M3K has 5 main menu categories: Browse Files, Category, Recording, Play settings, System settings.

  • Browse Files: allows to navigate the contents of the micro SD card in a folder view and order – users preferring to organize their files by folder will be glad with this  navigation option
  • Category: navigation is done through the id3 tags by: all songs, artist, album, genre, favorites, playlists, recently added.
  • Recording: menu to start recording mp3 files with the incorporated microphone
  • Play settings: configuration menu with all the settings related with playback such as gapeless playback, balance, volume limit, etc.
  • System settings: access to settings of the device such as brightness, USB mode, language, date, factory restore, etc.

The music playing screen shows varied information, including: album cover image, song name, play mode, elapsed time, track duration, number of track (x/x). Further details about the file can be accessed from the additional menu pressing the button with the 3 parallel lines. The additional information showed includes: file name, artist name, album name, album name, kHz, bits, track duration and file size.

The top bar of the screen has a smartphone like design with the clock time on the center, volume level (in numbers that ranges from 0 to 60), a card inserted confirmation icon and the battery charge with a 5-bar icon.

The user manual of the M3K is bundled inside the unit, you can read and access it at any given time – the FiiO M3K user interface is available in 10 languages.


Formats Compatibility

The FiiO M3K has a AKM AK4376A DAC that is capable of decoding and reproduce the following file formats:

  • DSD: DSD64(“.iso”“.dsf”,“.dff”)
  • APE(Fast): 192 kHz/24 bit
  • APE(Normal): 96 kHz/24 bit
  • APE (High): 96 kHz/24 bit
  • FLAC: 192 kHz/24 bit
  • WAV: 384 kHz/32 bit
  • Aiff:192 kHz/24 bit
  • Aif:192 kHz/24 bit
  • WMA Lossless: 48 kHz/24 bit
  • Apple Lossless: 192 kHz/24 bit
  • MP3
  • OGG
  • M4A
  • ALAC
  • ISO
  • DFF
  • DSF
  • CUE
  • LRC –  for displaying lyrics


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The FiiO M3K has all the ports placed on the bottom of the unit. The ports/connectors available are: a 3.5mm mini stereo jack to plug your headphones, a micro SD card slot and a micro USB port that can be used to charge the unit or to use their OTG functions and USB DAC features.

The device can be set to update the library manually or automatically.


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FiiO M3K connectors and ports
FiiO M3K connectors and ports



We measured the FiiO M3K frequency response and the results showed a perfectly flat response, while further tests revealed no added nor tamed down response on any given range nor any kind of coloring (see the frequency response curve scrolling down in this article).

Furthermore, we measured each of the 8 EQ presets offered by the FiiO M3K to evaluate how accurate their EQ is with true frequency response measurements.

As you will see from our measurements further below on this article, their EQ presets are incredibly accurate and precise, what you see on the 5 bands of each EQ preset, is truly being boosted and/or dialed down – quite impressive this degree of accuracy from such an affordable little device.

The FiiO M3K technical specifications list a frequency response of 5Hz-90,000Hz, with a noise floor of <2uV, SNR of 117dB and output impedance of <1dB.

FiiO ensures and recommends to use the FiiO M3K with headphones having an impedance between 16Ω and 100Ω. Nonetheless through out our tests, this little but powerful DAC/DAP was perfectly capable of driving headphones with higher impedance like the Beyerdynamic DT 990 PRO (250ohm version), Beyerdynamic DT 770 PRO (250ohm version).

This is also achieved thanks to their powerful output power that reaches ≥42mW (16Ω) and a SNR ≥117dB – to give you a rough idea, no smartphone is capable of reaching the power output that the FiiO M3K can deliver.


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FiiO M3K with Bowers & Wilkins
FiiO M3K with Bowers & Wilkins



The FiiO M3K has a wide variety of EQ presets that can be chosen and changed on-the-fly. The presets have a graphical 5-band equalizer that ranges from +6dB to -6dB – the frequencies on the EQ are 62Hz, 250Hz, 1kHz, 4kHz and 16kHz.

The 8 EQ presets available are: Rock, Classical, Jazz, Pop, Dance, Metal, Vocal and EQ Off (as of firmware version 1.0.5)


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The firmware of the FiiO M3K can be upgraded through it’s micro SD card.

Lately, the brand has released a new firmware v 1.0.5 with the following improvements:

  1. Fixed issue where there would be no sound output after reboot when ‘Resume’ function is set to ON
  2. Fixed issue where the display brightness was incorrect after waking up the screen if the ‘Screen timeout’ is set
  3. Fixed issue where the player might freeze or reboot automatically after certain operations
  4. Improved the power consumption under ‘Idle standby’ or ‘Sleep’ mode
  5. Improved issue where the micro SD card might not be read when waking up from ‘Sleep’ mode or starting playing after reboot
  6. Improved issue where some tracks were sorted incorrectly when visiting ‘Browse files’ or ‘All songs’
  7. Miscellaneous bug fixes.

The FiiO M3K firmware v1.0.5, can be downloaded here (M3K-FW1.0.5)

Update: A newer firmware upgrade has been released – firmware version 1.2.1. You can download the firmware v1.2.1 here (M3K-FW1.2.1)

As reported by FiiO, the M3K-FW1.2.1 firmware changes, fixes and improvements include:

  1. Added “Recording quality” option (High and low) under System settings;
  2. Added “Button light” option (under System setting) to adjust the brightness of buttons or turn off button light;
  3. Added “Theme” option and a brand new “Theme 2” (under System settings -> Theme -> Theme 1/Theme 2), with some UI changes inTheme 1;
  4. Fixed issue where the mono songs could not be played;
  5. Fixed issue where the folder cover could not be displayed;
  6. Fixed issue where some lyrics could not be displayed normally;
  7. Fixed issue where some tracks could not be sorted alphabetically;
  8. Fixed issue where some MP3 tracks might cause the auto reboot issue on theplayer;
  9. Miscellaneous improvements and bug fixes.

How to upgrade the FiiO M3K firmware

FiiO informs the following instructions/steps to safely upgrade the Fiio M3K firmware:

“… Incorrect operation might lead to system crash! Please read carefully before upgrading.
Using Micro SD card to update: Copy the M3K.fw file to the root directory of the micro SD card (FAT32 format recommended). Insert the micro SD card into M3K and hold the volume “+” and power button at the same time until the micro SD card upgrade dialogue pops up then the upgrading will begin. It will automatically reboot when the update finishes.

* Do not rename the firmware file.

* Do not create a new folder to store the firmware file, and please just copy the M3K.fw file to the root directory of your micro SD card.


1. One micro SD card (FAT/FAT32/EXFAT/NTFS format are fine but FAT32 is recommended). If update fails, please use a micro SD card of 32GB capacity, format the card and repeat the update procedure again.

2. Upgrading wouldn’t affect the files on the micro SD card.

3. Make sure the battery life is enough for update(fully charged battery is recommended)

4. Please don’t operate during upgrading

5. After the update, it is suggested to delete the M3K.fw file; You could check the firmware version via System setting -> About M3

6. After the firmware update, please update the media library.

ATTENTION!: Extreme caution should be taken when upgrading the firmware of the FiiO M3K or the unit could become non-functional.

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Scores Scores

FiiO M3K Scores

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Frequency Response (raw)

FiiO M3K Frequency Response Curve

FiiO M3K frequency response curve _ EQ OFF with Pioneer SE-CX8
FiiO M3K frequency response curve _ EQ OFF with Pioneer SE-CX8
Pioneer SE-CX8 for<a href= data-srcset=
FiiO M3K frequency response curve reference” width=”750″ height=”335″/> Pioneer SE-CX8 for FiiO M3K frequency response curve reference

FiiO M3K Frequency Response Curve – EQ Presets

Blue curve= EQ OFF; Red curve= EQ On

FiiO M3K with Pioneer SE-CX8
FiiO M3K with Pioneer SE-CX8

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FiiO M3K Technical Specifications

Screen size2.0 inches
Music PlayerYes
Max Card Size2 TB
Battery26 hours
Screen resolution320×240
Frequency Response5Hz-90KHz
PlugStereo mini plug
WeightApprox. 77.5g

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FiiO M3K Full technical specifications

reported by FiiO

Main Unit Name / Model No. M3K
Operating System Linux
CPU model Ingenic X1000/E,40nm
No. of cores Single
CPU operating frequency 1GHz
Keyboard Touch button Input method Touch button+Physical button
Special features Long battery life, Deep sleep, Recording, Repeat
User interface Deeply customized
Chips used SoC: Ingenic X1000/E,
Connectivity WiFi N/A Bluetooth N/A
Display screen
Display size 2.0 inches
Number of colours 262K
Display type IPS TFT
Viewable angle Full-view
Resolution 240×320
Pixel density(PPI) 200
Touchscreen  N/A
Storage expansion type Micro SD
ROM available to user N/A
Maximum storage expansion Theoretically 2TB (only one micro SD card slot)
Buttons and ports Buttons Touch button+Physical button Multifuctional button Playback control/Repeat
Headphone out (PO) Standard 3.5mm stereo jack decorated with metal ring
USB Micro USB2.0(Charging/Data transfer/OTG/USB DAC)
Line out (LO) N/A
Color Silver
Dimensions 90.8mm×44.2mm×12mm
Weight About 77.5g
Volume control 60 steps digital potentiometer
Recommended headphone impedance 16~100Ω
Equalizer 5-band EQ (±6dB),7 presets
Treble control N/A
Bass boost N/A
Balance control ±5dB
Gain control N/A
USB DAC Asynchronous USB Dac, up to 192kHz/24bit supported
Highest sample rate supported 384kHz/32bit
Power specifications
USB power adapter DC 5V/2A Recommended
Battery capacity 1100mAh Li-polymer battery
Charging indication Large charging icon shows on display when it’s off, small charging icon shows on upper right of
display when it’s on
Charging time  <2.5 h(DC5V/2A)
Battery indication Yes
Battery Life & Test Conditions
3.5mm headphone output:>24h
Volume 24 Load  M3 open earbuds (27 Ω)
Screen OFF Test File MP3 44.1kHz/16bit
Recording Supported
A-B Repeat Supported
Date&Clock Supported
USB OTG Supported
Headphone out specifications
Output power 1 ≥42mW(16Ω / THD+N<1%) Output impedance <1Ω(32Ω)
Output power 2 ≥25mW(32Ω /THD+N<1%)
THD+N <0.004%(1kHz/32Ω)
Frequency response 5Hz~90 kHz(-3dB)
Noise floor <2uV
SNR ≥117dB (A-weighted)
Peak output voltage 2.46Vp-p
File format support
Lossless: DSD:DSD64(“.iso”“.dsf”,“.dff”)
APE(Fast): 192 kHz/24 bit
APE(Normal): 96 kHz/24 bit
APE (High): 96 kHz/24 bit
FLAC: 192 kHz/24 bit
WAV: 384 kHz/32 bit
Aiff:192 kHz/24 bit
Aif:192 kHz/24 bit
WMA Lossless: 48 kHz/24 bit
Apple Lossless: 192 kHz/24 bit


FiiO M3K Photos

We highly discourage anyone from trying to apply our testings to your own earphones, the risk of damaging or permanently breaking your iems is absolutely probable to happen. With our standardized equalization and amplification tests we push the limits of the earphones to the extreme. If anyway you decide to do so, we cannot be held responsible of the damage done to your equipment. Do it at your own risk.

meze 99classics, meze 99neo, 1more quad-driverFiiO m3k

FiiO M3K