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FiiO M21 specifications and in-depth review

FiiO M21

Manufacturer: FiiO

The FiiO M21 is a full-featured digital audio player built on the Qualcomm Snapdragon 680 chipset and running Android 13, giving it the flexibility of a modern mobile platform alongside its dedicated audio hardware. It carries four Cirrus Logic CS43198 DAC chips in its design, supporting a wide range of audio file formats including MP3, FLAC, WAV, DSD, MQA, ALAC, and several others. The device ships with 64 GB of internal storage, a microSD card slot for expansion, and 4 GB of RAM to keep the Android environment responsive during use.

On the connectivity side, the FiiO M21 supports Bluetooth 5 with an unusually broad codec set that covers LDAC, LDHC, aptX, aptX HD, and AAC, as well as AirPlay and Wi-Fi. Wired listening is handled through both a 3.5 mm single-ended output and a 4.4 mm balanced output, with USB-C rounding out the audio output options. The signal-to-noise ratio is rated at 124 dB, the 4.7-inch LCD touchscreen resolves at 326 ppi, and the unit weighs 193 g with a thickness of 17 mm. Battery life is rated at 15 hours, with a charge time of approximately 1.5 hours.

Pros
  • Equipped with four Cirrus Logic CS43198 DAC chips and a 124 dB signal-to-noise ratio, indicating a well-specified audio output stage
  • Supports an extensive range of wireless audio codecs over Bluetooth 5, including LDAC, LDHC, aptX, and aptX HD, as well as AirPlay for network-based streaming
  • Offers both a 3.5 mm single-ended and a 4.4 mm balanced output alongside USB-C, covering multiple wired connection types
  • Plays back a wide variety of audio formats including DSD, DFF, MQA, FLAC, ALAC, APE, and more, reducing the need for file conversion
  • Comes with 64 GB of internal storage and an external memory card slot, providing flexible capacity options
  • Battery life is rated at 15 hours with a relatively short charge time of 1.5 hours
Cons
  • At 193 g and 17 mm thick, the physical size and weight may be noticeable for extended handheld use
  • The display resolution of 750 x 1334 px on a 4.7-inch LCD is modest and may appear less sharp compared to higher-resolution panels
  • Does not support wireless charging, requiring a wired connection every time the battery needs replenishing
  • Lacks weather sealing, so the device offers no protection against splashes or moisture
  • aptX Adaptive, aptX Lossless, and aptX Low Latency are not supported, limiting compatibility with certain newer Bluetooth audio devices
Who is this for?

The FiiO M21 is well-matched for dedicated audio enthusiasts who want a standalone player with serious DAC hardware, as the quad Cirrus Logic CS43198 configuration and 124 dB signal-to-noise ratio point to a device built around output quality rather than general-purpose use. Its support for formats like DSD, MQA, FLAC, and ALAC makes it a practical choice for listeners who maintain high-resolution audio libraries and want native playback without transcoding. The broad Bluetooth codec support — covering LDAC, LDHC, aptX HD, and AirPlay — also suits users who regularly switch between high-quality wireless headphones from different ecosystems. With 64 GB of internal storage plus an external card slot and a 15-hour battery life, it works well for extended listening sessions away from a power source.

Who is this NOT for?

Users who need a device that can handle outdoor or variable-weather environments will find the M21 limiting, as it carries no weather sealing whatsoever. The 193 g weight and 17 mm thickness also make it less appealing for those who prioritize a compact, lightweight carry — it is noticeably bulkier than a typical pocket-friendly player. Listeners invested in newer Bluetooth audio standards will hit a ceiling here as well, since the M21 lacks aptX Adaptive and aptX Lossless, which may matter for users pairing with compatible next-generation wireless gear. Additionally, those who prefer a sharp, high-resolution display for media browsing or UI interaction may find the 750 x 1334 px LCD underwhelming for that purpose.

General info:

internal storage 64GB
Audio outputs 3.5 mm, 4.4 mm, USB-C
DAC name Cirrus Logic CS43198 x4
Audio file types MP3, FLAC, WAV, APE, AIFF, WMA, ALAC, OGG, AAC, DSD, DFF, MQA
Battery life 15 hours
charge time 1.5 hours
has an external memory slot ✓
Signal-to-noise ratio (SNR) 124 dB
has wireless charging ✕
is weather-sealed (splashproof) ✕
RAM 4GB
Chipset (SoC) name Qualcomm Snapdragon 680
Android version Android 13

The FiiO M21 runs on a Qualcomm Snapdragon 680 chipset paired with 4 GB of RAM and Android 13, providing a capable foundation for a dedicated audio player. At the heart of its audio hardware are four Cirrus Logic CS43198 DAC chips, delivering a signal-to-noise ratio of 124 dB across three output options: 3.5 mm, 4.4 mm, and USB-C. It handles a broad range of formats including MP3, FLAC, WAV, APE, AIFF, WMA, ALAC, OGG, AAC, DSD, DFF, and MQA. The device comes with 64 GB of internal storage and supports external memory expansion via a card slot. Battery life is rated at 15 hours with a charge time of 1.5 hours. The M21 does not include wireless charging and is not weather-sealed.

Design:

screen size 4.7"
resolution 750 x 1334 px
pixel density 326 ppi
weight 193 g
Display type LCD
has a touch screen ✓
volume 139.876 cm³
width 68 mm
thickness 17 mm
height 121 mm

The FiiO M21 features a 4.7-inch LCD touchscreen with a resolution of 750 x 1334 px and a pixel density of 326 ppi. The unit measures 121 mm in height, 68 mm in width, and 17 mm in thickness, giving it a volume of 139.876 cm³. It weighs 193 g, which is consistent with its physical footprint as a dedicated handheld audio player.

Connectivity:

Bluetooth version 5
has aptX ✓
has LDAC ✓
has LDHC ✓
has aptX HD ✓
has aptX Adaptive ✕
has aptX Lossless ✕
has AAC ✓
has aptX Low Latency ✕
has AirPlay ✓
supports Wi-Fi ✓

The FiiO M21 supports Bluetooth 5 with a wide selection of wireless audio codecs, including LDAC, LDHC, aptX, aptX HD, and AAC, making it compatible with a broad range of Bluetooth receivers. It does not support aptX Adaptive, aptX Lossless, or aptX Low Latency. Beyond Bluetooth, the device includes Wi-Fi connectivity and AirPlay support, enabling wireless audio streaming over a local network.

Final Verdict

The FiiO M21 is a purposefully built digital audio player that centers its identity around serious DAC hardware and broad format compatibility, making it a compelling option for listeners who treat audio playback as a priority rather than an afterthought. Its quad Cirrus Logic CS43198 DAC configuration paired with a 124 dB SNR gives it a technically strong foundation, and the combination of balanced and single-ended wired outputs with wide Bluetooth codec coverage — including LDAC, LDHC, and aptX HD — means it accommodates a variety of listening setups without compromise. It does carry some practical trade-offs in terms of bulk, display resolution, and the absence of weather sealing or newer Bluetooth standards like aptX Adaptive, which narrow its appeal for more casual or on-the-go users. For those whose focus is high-resolution audio playback with flexible connectivity, the FiiO M21 delivers a well-specified, capable package that aligns closely with what a dedicated audio player in this category should offer.

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