FiiO M15S Review: A Portable Hi-Res Lossless Music Player for Enhanced Listening Experience

The FiiO M15S digital audio player is not a device for everyone. It’s actually a specialized device that only those with a discerning ear for music quality will appreciate. The average user who doesn’t dive deep into music might not find it particularly useful.

That being said, this player is one of the best ways to elevate your music listening experience. Paired with a great set of headphones, the FiiO M15S can deliver exceptional Hi-Fi audio quality. This player is best used in conjunction with lossless music services like TIDAL or Apple Music and a pair of headphones capable of handling lossless and Hi-Fi tracks.

I recommend using headphones with a neutral sound signature, ones that don’t undergo special tuning or coloring but aim to reproduce the artist’s original intent. I’ve tried various headphones, from simple TWS earbuds to Focal’s Utopia headphones.

Of course, the higher the quality of your headphones, the better the results. For those who want more from their music and wish to enjoy it anytime and anywhere, the FiiO M15S is an excellent choice. Yes, it’s quite expensive, but I assume that those reading this review understand the price of Hi-Fi equipment and are willing to invest in it. In that case, I highly recommend the FiiO M15S.


  • M15S main unit
  • Leather protective case
  • DK3S cooling base
  • PD charging/data cable
  • USB power cable for use with the cooling base
  • USB adapter
  • MicroSD card removal tool
  • User manual


The FiiO M15S’s design looks somewhat like a smartphone from a distance. It’s a bit shorter than the iPhone 14 Pro Max but noticeably thicker and heavier.

The body is primarily made of glass and aluminum, giving it a robust feel. At the bottom of the unit, there’s a USB-C charging port and a microSD card slot that supports storage of up to 2TB.

The power button, previous track button, pause/play button, and next track button are on the left side of the device. On the right side, you’ll find the lock switch, volume buttons, and an input mode selection button. The input mode selection button allows you to choose from the following options:

  • Pure Music Mode: An exclusive mode for immersive music experiences.
  • Android Mode: Allows the use of third-party apps, including streaming services.
  • AirPlay Mode: Wireless connection to iOS devices like iPhone and iPad, improving sound quality.
  • Roon Ready Mode: Roon Ready certified, suitable for true music enthusiasts.
  • USB DAC Mode: Functions as a DAC when connected to a computer or smartphone, significantly improving sound quality.
  • Bluetooth Mode: Supports SBC, AAC, aptX, aptX HD, aptX LL, LDAC, and aptX Adaptive, offering convenient high-quality wireless audio.

On the top of the device, there’s a very useful volume knob with 120 precise volume levels. It is surrounded by an LED ring that can be customized for brightness, operational status, color, and more. Next to the knob are various output interfaces, which include:

  • 2.5mm balanced headphone output
  • 3.5mm single-ended headphone output
  • 4.4mm balanced headphone output

Overall, the craftsmanship of the device is excellent, though it may feel a bit bulky compared to a smartphone. However, adding a fingerprint sensor for unlocking would make it even more perfect.


The FiiO M15S features a 5.5-inch 1440×720 display with responsive touch capabilities. The brightness is adequate, and the operating system is based on Android 10, featuring a clean, uncluttered UI with no pre-installed bloatware.

Users can watch videos and play less demanding games on this screen, but these are supplementary functions, as the device is primarily intended for professional music playback. The display doesn’t perform particularly well in bright sunlight due to its limited brightness.

Overall, this isn’t a flagship smartphone display, but it covers all the essential functions required of a professional music player.


As mentioned, the operating system is Android 10, which is somewhat outdated from a smartphone perspective.

From a hardware standpoint, Android performs smoothly on this device with accurate touch responses. The only issue you might encounter is with updates for some third-party apps. Android has already been updated to version 14, and some video apps may require a newer Android version for future updates. If FiiO doesn’t continue to update the system version, it could lead to fewer games and streaming apps being compatible in the future.

The M15S also comes with the FiiO app, which can scan all music on your MicroSD card or connect to a NAS media server for music playback. It’s essentially like other music player apps. The M15S also supports Roon Ready. Roon is similar to Plex, designed for Hi-Fi music playback, and is used by many audiophiles.

Diving into Android system settings, you’ll find

an audio section, which goes beyond typical smartphone settings. Here, you can fine-tune various audio quality aspects:

  • Output selection
  • Gain selection
  • Low-pass filter mode
  • Bluetooth audio codecs
  • Balance adjustment
  • Second harmonic adjustment

These settings allow users to make precise adjustments to various output details according to their listening preferences. FiiO also provides a dedicated tech support app to guide users on reference and usage of these settings. However, it might be a bit complex for those who have never used a Digital Audio Player (DAP) before.

In summary, the software and UI work well, offering a wide range of features. The professional output settings are especially notable. However, we hope that FiiO will upgrade the M15S to newer Android versions to ensure continued app compatibility.

Sound Quality

The FiiO M15S is not just a music player but also a powerful 8-channel DAC. You can use it as a desktop DAC by connecting it to your computer. Here are some performance features that enhance the sound quality of your computer output:

  • ES9038PRO DAC (desktop-level)
  • 4th-generation Digital Audio Purification System (DAPS)
  • Dual power supply modes
  • Five gain levels
  • Dedicated desktop mode
  • Automatic AUX DC power supply
  • Over-engineered power supply for clean power
  • Multi-stage audio circuitry
  • SBC/AAC/aptX/aptX HD/LDAC 2-way/BT 5.0

Listening to Apple Music Lossless or similar lossless music through the M15S is truly enjoyable.

Once you connect high-quality headphones, the sound quality delivered by the M15S is exactly what you’d expect: neutral and natural. Different headphones may produce varying sound signatures. What matters most to me is the clarity and volume that the M15S provides. It significantly elevates the sound quality to a new level.

In conclusion, this device performs exceptionally well in terms of both performance and sound quality. Considering its price of around 6,000 yuan, it offers excellent value.


After some usage, I found that the battery life of the M15S can vary significantly based on factors such as Bluetooth usage, gain level, and whether it’s in desktop or mobile mode. When mainly using wired headphones with platforms like Apple Music and NetEase Cloud Music, you can expect approximately 11 hours of battery life. It’s not exceptional but decent. With QC3+PD fast charging, it takes a bit over 3 hours to fully charge, which is reasonable.


The M15S is a professional-level audio device designed for users who have high demands for sound quality and music details. This device excels in both performance and sound quality, delivering an outstanding listening experience, especially for audiophiles and music enthusiasts. The pricing of the FiiO M15S is relatively high, but if you are willing to invest in an exceptional audio experience and have the budget for it, it’s a product worth purchasing.