FiiO M9 review: a compact, affordable and highly musical Hi-Res DAP


Mis à jour le 6 March 2021.

Equipped with a double Asahi Kasei AK4490 DAC and certified Hi-Res Audio, the FiiO M9 DAP is capable of powering hi-fi in-ear monitors and headphones with an impedance ranging between 16 and 300 ohms. In FiiO’s M DAP range, its intermediate size places it in between the tiny FiiO M5 and the larger FiiO M11, FiiO M11 Pro and FiiO M15. The FiiO M9 is therefore about the same size as the FiiO M6 and FiiO M7, allowing it to be easily slipped into a pocket without getting in the way.

Sold for 299 euros, does the FiiO M9 perform as well as its promising specs suggest?

We tested the FiiO M9 DAP with several pairs of hi-fi headphones, including the AKG K92.

FiiO M9: the brand

We aren’t going to touch on the history of the FiiO brand again, as we have already extensively covered the topic in our reviews of the FiiO M11 and FiiO M11 Pro.

As a quick recap, since it was founded in 2007, FiiO has forged itself a solid reputation in the DAP, portable headphone amplifier and earphone markets. Building on its experience, the Chinese brand now offers a very wide range of digital audio players, with models to suit all budgets and requirements in the FiiO M series:

FiiO M9: packaging & accessories

The FiiO M9 DAP comes in a cardboard box on which it is pictured, framed by the Hi-Res Audio, Bluetooth, aptX HD and LDAC logos. As well as the DAP, the box contains a transparent protective case (already on the player), the USB-A to USB-C charging cable, a mini-jack to RCA coaxial cable (for the digital output) and printed documentation. If you want to connect the DAP to your computer and hi-fi system or amplifier to use it as a USB DAC by setting the headphone output to Line-out mode, you will need to purchase a mini-jack to mini-jack cable (such as the NorStone IRK 280) or a mini-jack to RCA cable (such as the Real Cable iPlug J35M2M, for example).

The flexible transparent protective case that comes with the FiiO M9 DAP is a perfect fit and provides excellent protection.

FiiO M9: presentation

Certified Hi-Res Audio, the FiiO M9 DAP is equipped with a double AKM AK4490 DAC. It supports PCM files up to 24-bit/192kHz as well as DSD (64/128) files.

The FiiO M9 DAP is certified Hi-Res Audio, providing optimal playback of high resolution audio files (PCM 24/192 and DSD 64/128) thanks to its very wide frequency response (5Hz to 80kHz).

It also features an aptX HD and LDAC compatible Bluetooth receiver/emitter. Therefore, it can stream music wirelessly to Bluetooth headphones, but also receive music via Bluetooth from a smartphone or tablet.

During our review, we were impressed by the quality of the Bluetooth transmission, which was largely due to the player’s compatibility with the aptX HD and LDAC codecs. The latter preserve amplitude and don’t compress the dynamic range very much, which is an appreciable characteristic. However, Bluetooth’s relatively short range is a drawback: signal loss is frequent over 7 to 8 meters.

In Bluetooth DAC mode, the FiiO M9 wirelessly receives music played on a smartphone (here using the LDAC codec). Its DAC decodes the digital signal, which is then amplified to be listened through headphones.

The FiiO M9’s 2GB of internal storage is almost entirely taken up by the modified Android operating system, so it is necessary to invest in a micro-SD memory card to copy your music (maximum capacity of 2TB).

The FiiO M9 DAP’s micro-SD memory card slot accepts cards with a storage capacity up to 2TB.

With its WiFi connectivity, the FiiO M9 can access multiple online music services. Finally, its USB-C port can be used to operate this player as a USB DAC when connected to a computer. 

Double AK4490 DAC

The FiiO M9 includes two AKM AK4490 D/A convertors that are implanted in an entirely balanced structure. This is the same DAC that is used in the FiiO X5 III and iBasso DX150, as well as the prestigious Astell&Kern KANN and Questyle QP2R DAPs. This converter from the Japanese manufacturer’s Velvet Sound range is characterized by an excellent signal-to-noise ratio (SNR) and very low distortion.

Audiophile amplification

The FiiO M9 DAP’s amplification uses a pair of OPA1622 operational amplifiers that have a low level of background noise and distortion. Several low-pass filter settings are also available, as well as a two-position gain control (low/high) to adjust the output level according to the impedance and sensitivity of the headphones or earphones used.

The manufacturer has announced an output power of 170mW per channel into 32 ohms and 19mW per channel into 300 ohms for the 3.5mm mini-jack output, with an output impedance under 2 ohms. The FiiO M9’s relatively modest amplification means that it is best suited for use with headphones and earphones that have a low impedance (16 to 300 ohms according to the manufacturer’s recommendations) and high sensitivity rating.

Although the manufacturer recommends pairing the FiiO M9 with headphones that have an impedance under 300 ohms, it still manages to power a challenging model such as the Sennheiser HD540 Reference.

However, we still managed to push it to its limits by pairing it with the Sennheiser HD540 Reference open back headphones (600 ohms/94dB) with which it sounded rather good. With the gain set to High and the volume at halfway (60/120), we achieved a satisfactory sound level in a calm environment. You could easily push the volume slider up to 90 or even 100/120 to improve the dynamic range and bass reproduction without causing distortion. But be careful as the battery will run out pretty quickly (3 to 4 hours of autonomy with Qobuz via WiFi).

The FiiO M9’s audio settings menu provides several modes for the low-pass filter.

Customized Android

The FiiO M9 DAP runs on a customized version of Android optimized to transfer audio streams directly to the DAC, without any digital modification or interference. Functional and pleasant to use, the interface is rather responsive (more so than with the FiiO M6) once the chosen audio playback app is open. However, we did notice a slight delay between entering a command on the touch screen and it being applied, but it isn’t a huge problem.

The FiiO M9 DAP’s home menu features the icons of the installed apps. You must scroll up to reveal hidden icons.

Among the shortcuts on the home screen are the FiiO Music app, a file manager, access to the photo gallery, technical support where you can update the firmware, and access to the settings. You have to go into the latter’s audio section to activate the USB DAC mode and AirPlay.

Installing the apps

By default, the FiiO M9 includes the Tidal, Moov and KKBox online music service apps. However, it is possible to install other music apps such as Spotify, Qobuz, Deezer, Roon, Bandcamp, Amazon Music, SoundCloud and even TuneIn Radio to enjoy web radios on your DAP. As the Google Play Store isn’t available, you need to visit the manufacturer’s website ( to find the corresponding APK files. These official installation files must first be downloaded onto a computer before being copied onto the player’s memory. Then, simply go into the file manager to install them.

For our review of the FiiO M9, we chose the Qobuz, Deezer and Amazon Music apps to take advantage of our subscriptions and enjoy all our playlists and favorite tracks.

FiiO Music app

The FiiO Music app is essential on the FiiO M9 DAP as it is responsible for scanning and indexing the music stored on the memory card or in the player’s internal memory. It also allows you to access DLNA servers present on the local network if you store your music on a NAS.

The FiiO M9 DAP’s FiiO Music app has a simple and functional interface.

You can access music files in several different ways via the FiiO Music interface: you can directly access all tracks, or browse by artist, album or genre. It is also possible to create playlists and directly access the folders containing the audio tracks.


The FiiO M9 features a touchscreen that is a little over 8cm (3.2”) in diagonal with a 16:10 ratio. The display quality is satisfactory despite the screen’s low definition (480 x 800 pixels). It is enough to read the information on the screen, but when entering text using the keypad, the very small size of the keys can be inconvenient. Moreover, it isn’t easy to use the display outdoors during the day or in brightly lit rooms. The combination of the shiny coating and low brightness makes it difficult to read what’s on the screen (mirror effect). This issue has also been observed on many other DAPs, such as the FiiO M6 and the FiiO M7.

Depending on how bright the ambient light is and the colors of the album artwork, it can be difficult to see what’s on the screen.

Power supply

The FiiO M9 is powered by a rechargeable Li-Polymer battery with a capacity of 2350 mAh. The manufacturer announces a maximum of 10 hours of continuous playback with the unbalanced headphone output (3.5mm), which is consistent with what we have observed when using low-impedance IEMs as well as the Sennheiser Momentum Wireless headphones in passive wired mode (28 ohms). With a more demanding pair of headphones such as the Sennheiser HD540 Reference (600 ohm version), the player’s battery life is greatly reduced. The battery can be recharged quickly (approx. 2 hours) using the included USB-C cable, which can be connected to a powered USB port or a mains/USB charger.

USB DAC mode

When it is connected to a USB port on a computer, the FiiO M9 can be used as a USB DAC in asynchronous mode. In this configuration, the DAP’s internal clock handles sending the packets of digital data to the AK4490 converters. This operating mode considerably reduces jitter, providing a more precise and soft restitution.

In USB DAC mode, the FiiO M9 handles the vast majority of audio formats: FLAC, WAV, WMA, AIFF, APE, etc. up to 24-bit/192kHz; DSD 64/128 in ISO, DSF and DFF. Note that if you wish to play Hi-Res Audio files with a sample rate over 24-bit/96kHz, it is necessary to install a specific Windows software driver, present on the DAP’s memory.

The FiiO M9 used as a USB DAC with the Qobuz app on Windows 10. Note that the color of the FiiO logo underneath the screen changes according to the quality of the audio files: blue for standard and CD-quality files, green/yellow for hi-res files (PCM 24/96 and 24/192).


The FiiO M9 DAP features two headphone outputs: an unbalanced 3.5mm mini-jack output and a balanced 2.5mm mini-jack output. The first provides an output power of 170mW (32 ohms) and can power most hi-fi earphones and headphones on the market with an impedance somewhere in between 16 and 300 ohms. This output can also be switched to a digital S/PDIF coaxial line output. The balanced headphone output provides an output power of 195mW into 32 ohms (220mW into 32 ohms with the gain set to high).

On the left, the 3.5mm mini-jack output (can be switched to headphone, line and SPDIF outputs), in the middle, the balanced 2.5mm mini-jack headphone output and on the right, the FiiO M9’s USB-C port for charging the battery or connecting the player to a computer to use it as a USB DAC.

Key specifications

  • DAC: 2 x AK4490
  • OS: Android (customized version)
  • CPU: Samsung Exynos (Dual Core 1GHz)
  • Certified Hi-Res Audio
  • Compatible with Bluetooth (emission and reception), AirPlay and DLNA
  • 3.2” touchscreen

Compatible audio formats

  • DSD: DSD64/128 (“.iso”,“.dsf”,“.dff”), dst
  • APE FAST/High/Normal: 192kHz/24-bit
  • APE Extra High: 48kHz/24-bit
  • APE Insane: 48kHz/24-bit
  • Apple Lossless: 192kHz/24-bit
  • AIFF: 192kHz/24-bit
  • FLAC: 192kHz/24-bit
  • WAV: 192kHz/24-bit
  • WMA LOSSLESS: 96kHz/24-bit
  • MP3, OGG, WMA, AAC…


  • Maximum unbalanced output power: 170mW (32Ω/THD+N<1%)
  • Maximum balanced output power: 220mW (32Ω/THD+N<1%)
  • Frequency response: 5Hz to 80kHz
  • Signal-to-noise ratio: ≥ 118dB (unbalanced) / ≥ 113dB (balanced)
  • Channel separation: 72dB (unbalanced) / 98dB (balanced)
  • Balanced output THD: < 0.002% at 1kHz/32 ohms
  • Unbalanced output THD: < 0.002% at 1kHz/32 ohms


  • 1 x USB-C
  • 1 x 3.5mm mini-jack unbalanced headphone output, switchable to line or S/PDIF coaxial output (adaptor provided)
  • 1 x 2.5mm balanced headphone output
  • 1 x microSD memory card slot

Network connectivity

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


  • Version 4.2
  • Emission and reception
  • Supported codecs: LDAC, aptX, aptX HD, SBC

Power supply

  • Li-polymer battery
  • Capacity: 2350 mAh
  • Autonomy: up to 10 hours (45 hours in standby mode)


  • Dimensions (W x H x D): 52 x 109 x 13mm
  • Weight: 116g

FiiO M9: listening conditions

We tested the FiiO M9 DAP with the Sennheiser Momentum Wireless headphones in both wired and Bluetooth (aptX) mode, along with the AKG K92 wired headphones.

We tested the FiiO M9 DAP with the Sennheiser Momentum Wireless headphones.

We also used the DAP with several pairs of earphones, including the Sennheiser Momentum In-Ears.

The FiiO M9 DAP is a great match for the AKG K92 headphones which it drives very efficiently.

We listened to Hi-Res (FLAC and DSD) audio files that were stored on a memory card inserted in the DAP, but also via the Qobuz (Qobuz Studio subscription) and Deezer apps. To do so, the FiiO M9 was connected to the local network via WiFi.

We also tried the USB audio DAC mode by connecting the M9 to a computer (Windows) with the included USB cable. We listened to high resolution FLAC and DAD files stored locally on the Foobar2000 app, as well as our review playlists via the Qobuz Windows app (Wasapi Exclusive mode).

In USB DAC mode, we were able to listen to our playlists via the Qobuz Windows app on the FiiO M9.

FiiO M9: listening impressions

The FiiO M9 DAP provided a very balanced sound, with a lot of clarity and softness thanks to its double AK4490 DAC. The lows, which were rather lively and deep, were precisely positioned and didn’t bleed into the other frequency ranges. The vocals were nicely centered, textured and perfectly outlined. Live acoustic performances (guitar/vocals or piano/vocals) were reproduced with authenticity and presence, which helped convey the emotions of the music and the artist’s voice. The highs were detailed, precise and smooth, without any sibilance.

Overall, the sound was detailed, with bold attacks and obvious rhythm. Both the stereo spatialization and the depth were impressive, and the music stretched far beyond the limits of the headphones and earphones we used.

FiiO M9: compared to…

FiiO M6: the FiiO M6 lags behind the FiiO M9, whose musical performance is far superior, especially regarding the softness in the highs, which tend to generate sibilance with the M6. The lows are a little less harsh and seem more intense with the M9, which takes the lead in this frequency range. The spatialization is remarkable and the integration of the different frequency ranges is perfect for a player at this price point. 

iBasso DX150: also equipped with a pair of AK4490 DACs, the iBasso DX150 also provides a soft and natural sound. However, it outperforms the FiiO M9 with its more significant output power, 32GB of internal memory and more recent version of Android that provides access to the Aptoide play store. That said, it will set you back an extra €200!

FiiO M9: conclusion

With the FiiO M9, the Chinese manufacturer offers a mid-range DAP with almost unbeatable value for money. Although elegant, compact, intuitive and easy to use, it has a few flaws such as its limited and rather slow operating system. However, the most important aspects are there, with excellent musicality: balance, dynamism, softness and precision are all present with this DAP, which also knows how to unfold an extensive and beautifully spacious soundstage.

Although it isn’t theoretically designed to power “big” headphones, the FiiO M9 DAP pleasantly surprised us with these Sennheiser headphones.

The Chinese engineers have done an excellent job of integrating the double AK4490 DAC into this DAP, which simultaneously displays precision, detail and balance. Paired with headphones or earphones with an impedance under 100 ohms and a sensitivity rating over 100dB, it is capable of producing high volume while maintaining its battery life of about ten hours.

What we liked

  • The compact size and light weight
  • The simple and intuitive interface
  • The balanced, rich and natural sound
  • The USB DAC mode
  • The aptX, aptX HD and LDAC compatible bidirectional Bluetooth
  • The included protective case

What we would have liked

  • A less reflective screen
  • A more responsive OS
  • An app store

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