Review: FiiO M15


Mis à jour le 21 October 2020.

Sold for €1399, the FiiO M15 is the flagship model in the Chinese manufacturer’s range of DAPs and is the most expensive DAP ever created by the brand. Visually, this ultra high-end player features a new chassis that is more curved than those of the FiiO M11 and FiiO M11 Pro, which have more angled edges. But the biggest change takes place inside the device: the FiiO M15 swaps the M11 Pro’s double AKM AK4497EQ DAC for a pair of AK4499EQ DACs, the most recent and powerful model from the Japanese manufacturer Asahi Kasei Microdevices. The other components are in keeping with the DAC: a high performance XMOS USB interface to optimize data streams in USB DAC mode, NDK femtosecond clocks and an FGPA chip for data packet timing, symmetrical architecture with audiophile components, a large power reserve to drive high impedance headphones…

The FiiO M15 inspires confidence when handled. Its impeccable finish and its attractive curved edges make it pleasant to hold. It is heavier than the M11 Pro (307g compared to 232g), which bodes well for audio performance but risks stretching your pockets!

By releasing three DAPs with increasingly improved performance in quick succession, the Chinese manufacturer surprised everyone and somewhat baffled its fans. How good is this flagship with its double AK4499EQ DAC? Is it worth the upgrade and, above all, the doubled price compared to the FiiO M11 Pro? 

FiiO M15: the brand

As it has already been extensively covered in our recent reviews of the FiiO M11 and FiiO M11 Pro, we aren’t going to retrace the history of the FiiO brand again.

As a quick reminder though, since its creation in 2007 FiiO has managed to forge itself an excellent reputation in the DAP, portable headphone amplifier and earphone markets. Boosted by its experience, FiiO now offers a very wide selection of DAPs with models for every budget and all requirements. The FiiO M15 is the flagship model in the Chinese manufacturer’s range of DAPs which also includes the FiiO M11 Pro, FiiO M3K, FiiO M5, FiiO M6, FiiO M7, FiiO M9 and FiiO M11 models.

FiiO M15: packaging & accessories

The FiiO M15’s packaging is very luxurious. It comes in a hard black cardboard box that is covered by a cardboard sleeve adorned with a life size photo of the player. When we opened the cardboard box, we were surprised to discover a pretty, solid wood box with the FiiO logo elegantly engraved on the cover. Inside, the DAP sits in a block of compact packing foam. The screen and the back of the M15 are both covered by a protective film.

The FiiO M15 comes in a wooden box that adds to the luxurious feel of the packaging. We expected no less for 1399 euros.

The FiiO M15 comes with a USB-A to USB-C charging cable, a mini-jack to RCA coaxial cable (for the digital output), a tool to open the Micro-SD tray, a protective film for the back of the DAP and user guides. Unfortunately, the FiiO M15 doesn’t come with a protective case, so be careful of scratches and fingerprints!

FiiO M15: presentation

The FiiO M15 isn’t very different from the FiiO M11 and FiiO M11 Pro when it comes to features. Also certified Hi-Res Audio, the FiiO M15 features two AKM AK4499EQ DACs as opposed to the FiiO M11 Pro’s two AKM AK4497EQ DACs. Consequently, it supports PCM files up to 32-bit/384 kHz, DSD files (64/128/256) and MQA files (8x). 

The FiiO M15 is fitted with three headphone outputs – two balanced (2.5mm mini-jack and 4.4mm Pentaconn) and one unbalanced (3.5mm mini-jack) – that allow it to drive demanding headphones or a pair of earphones. Like the two M11 models, it features an aptX HD, LDAC and HWA compatible bidirectional Bluetooth controller to stream music wirelessly to a pair of Bluetooth headphones or earphones, but also to receive music from a smartphone or tablet, also via Bluetooth. 

Lastly, the FiiO M15 can be used as a USB DAC with any computer by connecting it to one of the USB ports using the included cable. It has 64GB of internal storage, 52GB of which are accessible for the user. It is possible to add to the storage by inserting a Micro-SD card (max. 2TB) in the dedicated slot.

The back of the FiiO M15 features the Hi-Res Audio and Hi-Res Audio Wireless labels.
The FiiO M15 DAP’s micro-SD tray can hold a card with a maximum capacity of 2TB.

Once connected to the local WiFi network and to the internet, the FiiO M15 can play music shared over the network and access several online music services. Lastly, with its USB-C port the DAP can be used as a USB DAC once it is connected to a computer.

New design

The FiiO M15 DAP’s silhouette deviates from that of the FiiO M11 and FiiO M11 Pro. The Astell&Kern-like angular edges have been replaced with softer lines and rounded sides on the black brushed aluminum chassis. The DAP is more pleasant to hold as a result.

The FiiO M15 has a much softer and more universal design than its predecessors whose angular edges looked a lot like those of Astell&Kern’s DAPs.

Slightly bigger than the FiiO M11 Pro, the FiiO M15 is also noticeably heavier. The position of the controls and headphone outputs has also been altered to make it easier to use the DAP when it is in your pocket. Consequently, the volume knob and the headphone outputs are now on top of the FiiO M15, while the micro-SD slot is underneath. 

A LED is present underneath the FiiO M15’s volume knob. You can choose to activate it or not.
The left side of the FiiO M15 features the playback controls, a customizable multifunctional button (bottom) and a “hold” locking button (top).

The playback controls are still on the left side of the DAP, which also holds the on/off button. Two new buttons are also present: a “Hold” switch that lets you lock the controls and deactivate the touch screen, and a customizable button that can be assigned one of the commands from the dedicated menu. Note that it is also possible to choose which control functions remain accessible and which are locked when the “Hold” mode is activated.

In the Settings/General/Hold switch settings menu, you can choose which control functions remain activated when the FiiO M15 is locked.
In the FiiO M15’s Settings/General menu, you can choose which function to assign to the DAP’s multifunctional button.

Double AK4499EQ DAC

A high-end DAP means high-end digital to analog converters. Staying loyal to Asahi Kasei Microdevices’ chips, FiiO has chosen the most powerful model in the Japanese manufacturer’s catalog. The FiiO M15 therefore features two AK4499EQ D/A converters embedded in an entirely symmetrical architecture.

This converter works across four channels compared to only two for the AK4497EQ, which directly impacts the output signal quality, mainly in terms of noise, details and sound spatialization… In comparison to the FiiO M11 Pro’s AK4497EQ converter, which is from the same Velvet Sound series, the improvements mainly concern two points: the signal-to-noise ratio (SNR) which goes from 128dB to 134dB and the distortion, which is reduced from -116dB to -124dB.
The FiiO M15 DAP uses two Asahi Kasei Microdevices AK4497EQ DACs.

Balanced architecture

The FiiO M15 DAP has an entirely symmetrical architecture and uses high-quality components. In addition to the two AKM DACs, it incorporates an XMOS XUF208 USB controller that supports audio streams in very high resolution in USB DAC mode. Two high-precision NDK crystal oscilloscopes and a programmable FPGA chip developed by FiiO’s engineers are tasked with optimizing the clock rate for each sampling frequency, very effectively reducing jitter.

The FiiO M15’s circuits also use ultra-low noise, high-precision resistors and dedicated high-efficiency, low-loss audio capacitors. As a result, the FiiO DAP has a large power reserve to efficiently drive not only any pair of earphones, but also the vast majority of hi-fi headphones on the market, including those with high impedance ratings and large drivers. It also has a dedicated mode for these headphones, named Circumaural Mode. 

The Circumaural mode increases the output power for headphones with high impedance. Consequently, the FiiO M15 had no trouble powering our trusty Sennheiser HD540 Reference headphones that we dug out for the occasion!

Customized Android 7.0

Like the FiiO M11 and FiiO M11 Pro DAPs, the FiiO M15 runs a customized version of the Android 7.0 (Nougat) operating system that has been optimized for musical playback. Audio streams are sent directly to the DAC without any involvement from the OS. The operating system’s interface is particularly smooth and includes the touch navigation that we enjoyed on the brand’s other high-end players. 

The FiiO M15 DAP’s home screen is similar to that of Android smartphones. Cleverly designed, the default wallpaper makes it look as if the DAP is transparent and that the two AK4499EQ DACs are visible.

The FiiO M15 DAP doesn’t provide access to the official Google Play Store but it is possible to install several Android-compatible apps via the FiiO Market app store. These include the Amazon Music, Deezer, Qobuz, Roon, Spotify and Tidal online music service apps. You can also download TuneIn to listen to web radios, as well as SoundCloud. 

Accessible when the FiiO M11 Pro is connected to the internet (WiFi), the FiiO Market provides downloads for several music apps.

The FiiO Market store also lets you download three other app stores, including APKPure, for access to a wider range of apps. Once downloaded, the apps chosen in these alternative stores simply need to be uncompressed using the DAP’s file manager. We recommend that you download the APKPure app store as it allows you to carry out updates for music apps such as Qobuz and Deezer, as FiiO Market doesn’t provide the latest versions of these apps. You can also download other apps such as Netflix or Amazon Prime Video, for example.

Mode selection

The FiiO M15 can easily switch from Android mode to the Pure Music, USB DAC or Bluetooth receiver modes. To do so, simply swipe downwards on the touchscreen then press “Mode selection”. The DAP then prompts you to switch from one mode to the other.

By swiping downwards on the screen, a menu is revealed that provides access to several features including the mode selector.

In Pure Music mode, the FiiO Music interface takes over. It only provides access to music stored on the device and shared over the local network when the DAP is connected to the home WiFi network. Consequently, the other apps are no longer accessible.  

The FiiO M15 works asynchronously when in USB DAC mode and connected to the USB port on a computer. The internal clock handles the timing of the data packets sent to the converter, which drastically reduces jitter. Playback is therefore much more precise and smoother.

In USB DAC mode, you can enjoy the high-quality conversion of the FiiO M15’s AK4499EQ DACs with Hi-Res music using the Foobar 2000, Audirvana and Qobuz apps, among others.

In this mode, the FiiO M15 supports most audio formats: FLAC, WAV, WMA, AIFF, APE, etc. up to 32-bit/384kHz; DSD 64/128/256 in ISO, DSF and DFF. If you wish to play Hi-Res Audio files with a sample rate higher than 24-bit/96kHz, it is necessary to install a special Windows software driver that is stored in the player’s memory. 

Screen and navigation

The FiiO M15 has the same 5”, 18:9 format screen as the M11 and the M11 Pro. Its advantages and flaws are therefore identical: it is bright, well-contrasted, and offers HD resolution with rich colors, but it suffers from a mirror-like effect because of its shiny coating. It is still difficult to read information on the screen in bright environments. 

The FiiO M15 DAP’s central processor is still the Samsung Exynos 7872 hexa-core processor combined with 3GB of RAM. Navigation is just as smooth and the interface is just as responsive as it is with the M11 Pro.

Power supply

The FiiO M15 uses a rechargeable 7490mAh battery that provides a maximum of 15 hours of continuous playback via the 3.5mm mini-jack output (9 hours with the balanced outputs) and up to 75 days of autonomy in standby mode. The battery takes about 3 and a half hours to charge. This is done by connecting the included USB-C cable to a powered USB port of to a mains/USB charger.


The FiiO M15 has three headphone outputs: an unbalanced 3.5mm mini-jack output, one balanced 4.4mm mini-jack output (Pentaconn) and one balanced 2.5mm mini-jack output. The unbalanced output has an output power of 285mW (16 ohms) that can reach 420mW in Circumaural mode. As a result, it can power a pair of IEMs or hi-fi headphones (up to 600 ohms). This connector can also be used as a coaxial S/PDIF output. The balanced outputs provide 420mW into 16 ohms and 120mW into 300 ohms (up to 280mW into 300 ohms in Circumaural mode).

The FiiO M15’s headphone outputs are all at the top of the DAP. To the left, the 3.5mm mini-jack output, in the center the 2.5mm balanced output and to the right, the 4.4mm Pentaconn balanced output. 
The USB port that is used to both charge the player and use it as a USB DAC is located on the bottom of the FiiO M15, next to the micro-SD port.

Key specifications

  • DAC: 2 x AK4499EQ
  • OS: Android 7.0 (customized version)
  • CPU: Samsung Exynos 7872 (14nm)
  • Certified Hi-Res Audio & Hi-Res Audio Wireless
  • Bluetooth, AirPlay and DLNA compatible
  • 5” touchscreen

Compatible audio formats

  • DSD: DSD64/128/256 (“.iso”, “.dsf”, “.dff”), DST ISO
  • DXD: 352.8K
  • APE FAST/High/Normal: 384kHz/24-bit
  • APE Extra High: 192kHz/24-bit
  • APE Insane: 96kHz/24-bit
  • Apple Lossless: 384kHz/32-bit
  • AIFF: 384kHz/32-bit
  • FLAC: 384kHz/32-bit
  • WAV: 384kHz/32-bit
  • WMA LOSSLESS: 96kHz/24-bit
  • MP3, OGG, WMA, AAC… 


  • Unbalanced output max output power: ≥490mW (Over-ear Mode/32Ω /THD+N < 1%)
  • Balanced output max output power: ≥800mW (Over-ear Mode/32Ω / THD+N < 1%)
  • Line output frequency response: 5Hz to 90kHz (-3dB)
  • Headphone outputs frequency response: 20Hz to 90kHz (-3dB)
  • Signal-to-noise ratio: 121dB (unbalanced) / 122dB (balanced)
  • Balanced output THD: <0.0006% at 1kHz/300 ohms
  • Unbalanced output THD: <0.0005% at 1kHz/33 ohms
  • Balanced outputs channel separation: 103dB (1kHz/33 ohms)
  • Unbalanced output channel separation: 77dB (1kHz/33 ohms)


  • 1x USB
  • 1 x unbalanced 3.5mm mini-jack and coaxial S/PDIF output (adapter included)
  • 1x balanced 2.5mm headphone output
  • 1 x balanced 4.4mm headphone output (Pentaconn)
  • 1 x tray for a micro-SD memory card

Network connectivity

  • WiFi: 2.4/5G
  • DLNA & AirPlay compatible


  • Version 4.2
  • Emission and reception
  • Bluetooth transmitter (v4.2): HWA, LDAC, aptX HD, aptX, SBC
  • Bluetooth receiver (v5): SBC, AAC, aptX, aptX LL, aptX HD, LDAC

Power supply

  • 3.8V Li-polymer battery
  • Capacity: 7490mAh
  • Battery life: up to 15 hours (75 in standby)


  • Size (WxHxD): 75 x 134 x 18mm
  • Weight: 307g

FiiO M15: test conditions

To review the FiiO M15 DAP, we paired it with the Sennheiser Momentum M2 Wireless headphones in both wired and Bluetooth (aptX) mode.

The FiiO M15 DAP with the Sennheiser Momentum M2 Wireless headphones using an unbalanced wired connection.

We also used the FiiO FH7 in-ear headphones with their original cable (unbalanced, 3.5mm mini-jack), but also a balanced FiiO cable (2.5mm mini-jack).

The FiiO M15 DAP with the FiiO FH7 earphones (balanced cable).

We listened to Hi-Res files (FLAC and DSD) stored on the DAP’s memory. We were also able to enjoy our Qobuz (HiFi Sublime+ subscription) and Deezer playlists (Family subscription, MP3 320kbps) via their respective apps after connecting the FiiO M15 DAP to the local WiFi network using a Netgear Orbi router. 

We also tested the DAP’s audio DAC mode by connecting it to a computer (Windows) using the included USB cable. Like with the brand’s other models, to do this you first have to install the drivers located in the DAP’s memory. They are accessible via the file manager once the device is connected to the computer via USB (file transfer mode activated on the player).

We listened to high resolution FLAC and DSD files stored on the computer using the Foobar 2000 app (FiiO ASIO Driver), as well as our test playlist in the Qobuz Windows app (Wasapi Exclusive mode).

FiiO M15: listening impressions

Right off the bat, we felt that the FiiO M15 was a serious step up from the FiiO M11 Pro. Overall, the sound was more intense, detailed and precise. The spatialization was also much better with a lot of room to breath. The lows were more powerful while still being flawlessly controlled, the mids were more textured and realistic compared to those of the M11 Pro, and the highs seemed smoother and more precise. The dynamic shifts were excellently handled, the transients incredibly fast. We could hear how much power the FiiO M15’s amplification has under its belt. We enjoyed listening to music with the M15 so much that we were constantly turning the volume up.

Playback via the Qobuz app

We listened to the track “At Wit’s End” from the Pirates of the Carribean: At World’s End soundtrack. From the very first notes, we could tell that we were going to enjoy all of the track’s dynamic range and harmonic diversity. The highs soared and were bright, yet remained delicate and transparent. The lows were heavy, abyssal, and highly nuanced. The attacks were bold, the instruments well-outlined, the vocals and choirs aerial. The soundstage was wide and deep. At 3’08” when the strings unfolded, supported by phenomenal lows, the FiiO managed to keep pace. Everything stayed perfectly in place despite the intensity of the piece. 

The more low-key music box theme followed, underlined by an ethereal violin and full of nuance and levity before the authoritative brass instruments took over once more. From 6’30”, when the track became frenzied, the FiiO M15’s power reserve made all the difference. The percussion instruments packed a punch, the brass instruments were extremely vivid, the lows were monumental, but everything was controlled. We were thoroughly entertained and were swept away by the parts of the track that soared. 

Playing Hugh Coltman’s track “Civvy Street” (24-bit/44.1kHz, from the album Who’s Happy? on Qobuz) on the FiiO M15 allowed us to measure the qualities of this Chinese DAP: monumental lows, huge dynamic range, the singer’s voice was textured and well-outlined, the brass instruments had substance… A real treat!

In a completely different genre, Tracy Chapman’s song “The Love That You Had” (from the album Matters of the Heart) revealed the FiiO M15’s talent. The DAP managed to get the most out of this CD-quality recording (16-bit/44.1kHz). The lows had impact and magnitude that we had never before heard with this track. The cymbals hits were light, precise and incisive. The artist’s voice was robust and unfolded very naturally while standing out from the guitar and percussion. Once again, the track was remarkably spacious. The dynamic range was also remarkable.

On “Preach” (24-bit/44.1kHz, from the album When I Wake Up), Maverick Sabre’s voice was beautifully textured. His breathing was clearly audible and we could hear when he clicked his tongue at the ends of words. Once again, the dynamic range was colossal, especially when the backing vocals unfolded and the bass guitar grew in intensity. Despite this, the singer’s voice and the cymbals remained perfectly clear.

DSD & FLAC playback (internal storage & USB DAC mode)

We then switched to the Pure Music mode before playing Hotel California from the eponymous album (DSD64). With this track that we’ve listened to time and time again, the FiiO M15 really did the bassline justice. It was beautifully deep and the percussion instruments were perfectly outlined. We were once again impressed by the overall presentation, which was very extensive, in which the instruments stood out without ever obscuring one another, nor disguising the singer’s voice. 

We really enjoyed listening to Hotel California (DSD64) with the FiiO M15. Magnitude, spatialization, impact, details… nothing was missing!

On “Don’t Stop ‘Til You Get Enough” (FLAC 24/96, from Michael Jackson’s album Off the Wall), we were literally captivated by the dynamics of the track, which kept us hooked until the very end. The FiiO M15 managed to precisely position each sonic element both horizontally and vertically. Despite the rapid rhythm and the dynamic range, and much to our delight, everything remained structured.

FiiO M15: compared to…

FiiO M11 Pro: there is a definite “wow effect” when switching from the M11 Pro to the M15. The Chinese manufacturer previously enchanted us with its THX AAA-78 enhanced DAP, but the M15 is clearly in a whole other dimension. This player delivers music with an ease and naturalness that is usually only found with more expensive models. Admittedly, it is double the price of the M11 Pro, but at the same time our musical enjoyment was also doubled. Bolder transients, more intense and deeper in the lows, masterful with the dynamic shifts, the FiiO M15 is also more precise and detailed. Moreover, it excels in positioning vocals and instruments in the soundstage. Lastly, we can turn the volume up without worrying about the song coming apart. Everything stays in place. 

Cayin N8: we had the same feeling of entering another realm when listening to the Cayin N8. These two Chinese DAPs are unparalleled when it comes to bringing music to life. The M15 equals the N8 in terms of magnitude, spatialization and details. The same goes for its amplification, which allows the most demanding headphones to reach their full potential by making the most of their dynamic qualities. Naturally, we didn’t experience the warmth of the tubes with the FiiO. For now, the Cayin N8 is unique in this regard. Despite this, rarely have we enjoyed a DAP as much as the M15. 

FiiO M15: conclusion

In our opinion, the FiiO M15 is the best DAP in its price range and you would have to invest a lot more to find a better model. We were pleased to find all the aspects that made the M11 and M11 Pro models so successful (responsive Android interface, intuitive to use, remarkable build quality, balanced and unbalanced headphone outputs, USB DAC mode, a smooth, rich, and balanced sound…) but with even more energy and dexterity. Capable of providing an immense dynamic range, the M15 also impresses with its ability to spatialize the soundstage. No matter the style of music we listened to, we were enchanted by the ease, smoothness and naturalness of the restitution. 

The FiiO M15 undeniably marks a turning point for the Chinese manufacturer, who is now one of the market leaders. 

What we liked

  • The remarkable spaciousness and spatialization
  • How it handled the dynamic shifts
  • The output power
  • The powerful, deep lows
  • The smoothness of the interface and the responsiveness of the the touchscreen
  • The numerous features, including the USB DAC mode
  • The remarkable build quality

What we would have liked

  • An anti-reflective filter on the screen
  • For a protective case to have been included

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Traductrice et rédactrice avec des goûts très éclectiques en matière de musique et de cinéma. Lorsque je ne suis pas au travail, vous pouvez me retrouver en train de regarder “Lost in Translation” de Sofia Coppola pour la centième fois, ou d’écouter un disque de David Bowie, Kate Bush, Joy Division ou Daft Punk sur ma platine Rega Planar 1. Étant d’origine britannique, je suis également adepte de séries à l’humour absurde comme Monty Python’s Flying Circus et The Mighty Boosh !

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