FiiO M21 review: precision and transparency in the palm of your hand

Priced at €329, the FiiO M21 DAP is positioned in between the affordable JM21 and the more ambitious M23. With it, FiiO promises to generalize technologies inherited from its high-end models, in a compact, affordable format. Its symmetrical architecture uses a Cirrus Logic CS43198 quad DAC, capable of processing PCM streams up to 32-bit/384kHz and native DSD256. This design is accompanied by 3.5mm mini-jack and 4.4mm balanced jack headphones outputs, delivering up to 950mW per channel. Running on Android, like the rest of the brand’s recent range, the FiiO M21 provides direct access to streaming services, with an interface similar to that of modern smartphone users.

Presentation

Design

Visually, the FiiO M21 retains the aesthetic DNA of the brand’s previous models, with an exemplary finish that makes the device feel premium. Its chassis is made entirely of aluminum alloy for robustness and durability. The rear abandons the carbon-fiber pattern of the previous FiiO M11 in favor of a frosted glass panel for a better grip. For ease of transport, the FiiO M21 is the brand’s most compact model after the JM21, measuring 6.8cm wide, 12cm high and 1.7cm thick. Combined with a weight of 193g, this format makes it easy to slip into a jacket or trouser pocket.

The layout of the FiiO M21’s controls reflects a real concern for ergonomics. Buttons are logically distributed on both sides of the device, facilitating intuitive use without even having to take the player out of your pocket. The right-hand side houses the playback buttons, allowing you to start, pause or switch between tracks with a natural gesture. On the left edge are the power button, the volume control and a Hold selector that locks the touchscreen, leaving control solely to the physical keys. This security feature is invaluable on the move, so as not to interrupt listening if a button or the screen is accidentally pressed. Volume control is achieved in highly progressive 1 dB steps, offering appreciable precision, even if handling remains less intuitive than the M23’s touch control. In addition, a specific control provides access to the desktop mode for boosting power when the device is powered from the mains. Finally, a multifunction button can be assigned to a number of actions, such as shuffle, filter adjustment, equalization, or switching to USB or Bluetooth DAC mode.

The FiiO M21 is also the first model from the brand to introduce a dual USB port on a DAP of this range. One is reserved for charging, while the other is dedicated to data transfer and use as a USB DAC. These ports are cleverly placed underneath the device, facilitating access when installed on a desktop dock. This dual USB port enables the addition of a true desktop mode, allowing the device to be continuously powered from an AC adapter (not included) to increase amplification power. This makes the FiiO M21 an excellent streamer, DAC or headphone amp for sedentary use, whether on a desk or on the living-room hi-fi system. Finally, the 3.5mm mini-jack and 4.4mm jack outputs have been reorganized on top, simplifying connectivity when the player is carried in a pocket.

On the front, the FiiO M21’s screen lags behind current standards somewhat. With a diagonal of 4.7″ and a resolution of 750×1334 pixels, it’s on a par with the screen that equipped the iPhone 7 almost 10 years ago. So we won’t be choosing this player for video viewing or ultra-defined display, but that’s not its primary vocation. On the other hand, the screen is perfectly suited to music management, offering user-friendly, intuitive navigation. Its high brightness effectively compensates for reflections outdoors, guaranteeing good legibility, even in bright sunlight. On the other hand, the absence of automatic brightness adjustment can also be seen as a shortcoming, especially for outdoor use where you frequently switch from a bright to a darker environment.

Behind this modest display lies much more modern electronics. The Snapdragon 680 processor, backed up by 4GB RAM, ensures remarkable responsiveness, worthy of many recent smartphones. Browsing a vast music library, launching a streaming app or switching from one menu to the next is smooth and seamless, with an experience similar to that of a modern smartphone.

Quadruple DAC Cirrus Logic

The brand has made the ambitious choice of integrating four Cirrus Logic CS43198 DACs, working in parallel at 8 channels within a fully balanced architecture. Such a configuration, usually reserved for much more expensive portable players, drastically reduces noise and distortion while improving channel separation. To guarantee the most accurate conversion possible, FiiO relies on a fifth-generation FPGA controller, supported by a dual quartz oscillator clocked at 49.152MHz and 45.158MHz, to limit jitter and ensure perfect stability of digital streams.

This design allows playback of Hi-Res files up to 32-bit/384kHz and native DSD256. Admittedly, some very high-end models boast higher theoretical compatibilities, up to 32-bit/768 kHz and DSD 1024, but in reality it’s exceptional to encounter such formats in everyday use. In practice, then, the M21 covers most needs, from high-resolution personal libraries to lossless streaming.

High amplification power

The care taken with the FiiO M21’s internal architecture translates into a strict separation between the digital and analog stages, each isolated and powered independently to minimize interference. The analog circuit itself benefits from several separate power supply lines, including one specifically dedicated to the headphone amp. The latter adopts a two-stage design: a first preamplifier section manages the signal voltage, while a second power stage ensures the current expansion required to efficiently power all types of headphones.

To preserve signal purity, FiiO uses carefully selected components, including tantalum capacitors renowned for their extremely low noise levels. The figures speak for themselves: in battery operation, the M21 delivers up to 290mW into 32 ohms with the unbalanced output, and 720mW via the 4.4mm balanced output. This is more than enough power to drive the vast majority of headphones and in-ear monitors on the market, including demanding hi-fi models. For high-impedance headphones or particularly power-hungry planars, the FiiO M21 can go even further with its Desktop mode. Powered by an external USB source compatible with Power Delivery 2.0 or 3.0, it boosts power to 405mW into 32 ohms in unbalanced, and up to 950mW in balanced. Enough to rival real sedentary headphone amplifiers. In order to adapt to the varying sensitivities of headphones and earphones, three gain levels are available. In addition, the 3.5mm and 4.4mm mini-jack outputs can be set to line level, enabling the FiiO M21 to be used as a source with a hi-fi amplifier or active speakers.

Android and streaming

The FiiO M21 runs on Android 13, offering a familiar interface for Android smartphone users. Thanks to the Google Play Store, it’s possible to install any mobile app, especially online music services such as Deezer, Spotify, Tidal and Qobuz. These various apps are perfectly integrated, with an experience identical to that provided by the mobile versions. In addition to Android, the M21 offers a Pure Music mode. In this mode, the FiiO Music interface takes over, only providing access to stored tracks and music shared on the local network. Other apps are no longer accessible. Finally, the player can be configured as a USB DAC, AirPlay receiver or Bluetooth receiver.

In Bluetooth mode, the FiiO M21 can receive music from a smartphone, tablet or computer via a Bluetooth 5.0 controller. It supports most Bluetooth codecs, including the classic SBC and AAC, as well as high-resolution codecs such as LDAC. Naturally, it is Hi-Res Audio Wireless certified, making it a serious option for wireless listening. What’s more, the M21’s Bluetooth controller is reversible, allowing it to be paired with wireless headphones or earbuds. In this mode, the same codecs are used, with the addition of Bluetooth aptX HD and LHDC.

Battery or mains powered

The FiiO M21 is unique in that it can be powered by battery or USB. For portable use, it relies on a 4000 mAh battery that FiiO claims will provide up to 15h of listening time on the unbalanced output and just over 12h30 on the balanced one. These figures prove to be true in practice, with even slightly longer autonomy via the unbalanced output when listening at moderate volume. On the other hand, in a more demanding scenario with 300-ohm balanced headphones and WiFi, the battery life is closer to nine to ten hours. Recharging is fast, with a Power Delivery 2.0-compatible charger providing a full charge in just 1.5 hours.

At home, the FiiO M21 can switch to desktop mode to preserve its battery. When this mode is activated and the Type-C power port is connected to a fast charger, the player bypasses the internal battery to avoid charge/discharge cycles and optimize battery life. This mode also activates the Super High Gain mode to boost output power. This makes it a very attractive desktop headphone amplifier for powering demanding headphones. It should be noted, however, that this operation causes the player to heat up significantly, which is normal but should be kept in mind during prolonged use.

Installation and configuration

Right from the start, the FiiO M21 shows exemplary simplicity. Adding a Wi-Fi connection, choosing a language and installing streaming apps are all it takes to start listening to music in just a few minutes. The experience is immediate, with no tedious configuration. Familiarity with the interface is fast, especially for those used to Android devices. If need be, you can fine-tune the sound reproduction as you wish, thanks to a ten-band graphic equalizer, the oversampling filters offered by the DAP and the different gain levels that allow you to adapt the output power to the headphones or earphones you’re using.

For this test, we paired the FiiO M21 DAP with the FiiO FT1 Pro and Meze 105 Silva open-back headphones, as well as the FiiO FT1 and Meze 99 Classics closed-back headphones. We listened to Hi Res FLAC and DSD audio files stored on a micro SD card, as well as 24-bit/192kHz tracks streamed from Qobuz.

Listening impressions

From the very first listening session, the FiiO M21 set the tone with a neutral, analytical reproduction. The key word here is authenticity, with a minimum of intervention, leaving it to the headphones and recordings to impose their personality. Transparency was exemplary, with no background noise and incredibly clear timbres. Vocals emerged with precision, instruments stood out clearly from one another, and the soundstage was pleasantly airy. Without reaching the holographic breadth of players twice or three times as expensive, such as the FiiO M23, the M21 managed to create a well-structured soundstage where each instrument was correctly positioned.

The highs soared with extension and clarity. They added shine to the cymbals, strings and breaths in recordings, while remaining controlled. On complex tracks such as ZZ Top’s La Grange, we noticed a slight brightness with some headphones that were too neutral or that already leaning towards harshness. However, the overall sound remained natural and sufficiently well controlled to avoid any excessive sibilance.

The almost total absence of noise allowed us to fully appreciate the micro-dynamics and the most subtle passages of recordings. Dynamics were solid, with a good reserve of energy in the attacks and excellent transient control. The bass was exemplary. The lows descended with assurance and without excess. They favored clarity over massiveness, offering firm, precise bass. Some users may find this register a little timid if they’re looking for meaty bass on electronic or pop music, but this restraint is in keeping with the FiiO M21’s overall philosophy of neutrality.

The midrange also benefited from the player’s analytical qualities, with vocals expressing themselves with accuracy and naturalness, although sometimes they were a little timid. Acoustic instruments displayed a rich texture that is unexpected in this price range. There was a slight coldness, particularly with hushed jazz ensembles, where the velvety tones of the saxophones and the roundness of the grand piano seemed more restrained than enveloping. But this approach reflects a desire for authenticity: the M21 reproduces music as it is recorded, without attempting to artificially soften the edges.

FiiO JM21 vs FiiO M21

Compared to the entry-level FiiO JM21, the FiiO M21 is clearly a step up. Where the JM21 focuses on the essentials, with a simplified architecture and a pleasant but less accomplished reproduction, the M21 introduces a much more ambitious design: quadruple Cirrus Logic DAC instead of two, balanced architecture, more meticulous power supply with independent isolated modules for each section, and increased amplification power. The results are immediately apparent, with a wider soundstage, clearer instrument separation and significantly enhanced dynamics. And let’s not forget the Desktop mode, unprecedented at this price level, which transforms the M21 into a true sedentary DAC/AMP.

Who is this DAP for?

The FiiO M21 is aimed above all at discerning music lovers who want to enjoy neutral, precise sound reproduction, without having to invest in a mid-range DAP at an elitist price. It’s perfect for those who listen to their music both on the move and at home, thanks to its decent battery life and its Desktop mode, which transforms it into a real DAC and sedentary amp. This player is also aimed at users familiar with streaming services, who will appreciate Android 13’s fluidity and compatibility with all platforms. Those with a personal high-resolution library will also find something to their liking, with 32-bit/384kHz PCM and DSD256 compatibility ensuring virtually total support for the available formats.

FAQ – Frequently asked questions