FiiO M21 VS HiBy R6 III

At their core, the FiiO M21 and HiBy R6 III are built on a remarkably similar foundation: both pack the same Cirrus Logic CS43198 x4 DAC configuration, identical 64GB internal storage, 4GB of RAM, and offer the same trio of audio outputs (3.5 mm, 4.4 mm, and USB-C). Their format support is functionally equivalent as well, covering all major lossless and lossy codecs including DSD and MQA. For a buyer focused purely on audio hardware parity, these two devices start from nearly the same place.

The differences emerge in the platform and endurance specs. The M21 runs on a Snapdragon 680 paired with Android 13, while the R6 III uses the older Snapdragon 665 on Android 12. In practice, the 680 is a more modern, efficient chip, which likely contributes to the M21's superior real-world stamina: 15 hours of battery life versus 13 hours on the R6 III — a meaningful gap for long listening sessions or travel days. The M21 also recharges faster, needing just 1.5 hours compared to the R6 III's 2 hours. The R6 III does edge ahead on SNR at 126 dB versus the M21's 124 dB, a 2 dB difference that is technically measurable but unlikely to be audible in real-world use.

Overall, the FiiO M21 holds a clear practical advantage in this group: a newer chipset, a more current Android version, longer battery life, and faster charging all tip the scales in its favor. The R6 III's marginal SNR lead does not meaningfully offset these platform-level advantages for most users.

The two devices take noticeably different approaches to physical design. The FiiO M21 is the more compact and significantly lighter option at 193 g, compared to the HiBy R6 III's heftier 250 g — a 57 g difference that is immediately perceptible when holding either device for extended periods. For commuters or gym users who pocket their player, the M21's smaller footprint and lower mass translate directly into greater day-to-day comfort.

On the display front, the trade-offs are more nuanced. The R6 III offers a larger 5″ screen, which benefits navigation and album art browsing, but its 294 ppi pixel density trails the M21's 326 ppi on a 4.7″ panel — meaning the M21's smaller screen is actually sharper. The R6 III specifies an IPS LCD panel, which typically delivers better viewing angles and color accuracy than a standard LCD, partially compensating for the pixel density gap. The M21's display type is listed simply as LCD without the IPS designation, leaving that advantage with the R6 III for screen quality.

Taken together, the FiiO M21 holds the stronger design edge for portability-focused users: it is lighter, more pocketable, and sharper. The R6 III counters with a bigger screen and likely better panel quality, making it the preferable choice for those who prioritize a more immersive visual interface over compactness — but the weight penalty is substantial and hard to ignore.

Wireless connectivity is largely a shared story between these two players. Both run Bluetooth 5 with Wi-Fi support, and both cover the most important high-quality audio codecs: LDAC, aptX HD, aptX, and AAC. For the vast majority of users pairing either device with a quality wireless headphone or IEM, this common codec foundation means real-world wireless audio performance will be comparable.

The differentiators are specific but meaningful depending on your ecosystem. The FiiO M21 adds LDHC (also known as HWA), a high-res wireless codec that supports up to 900 kbps and is particularly relevant for users with compatible Huawei or HiBy-ecosystem earphones. More broadly useful is the M21's support for AirPlay, which opens seamless streaming integration with Apple devices and AirPlay-compatible speakers — a genuine convenience advantage for users in the Apple ecosystem. The HiBy R6 III supports neither LDHC nor AirPlay.

The FiiO M21 takes a clear edge in connectivity. Its additional LDHC codec broadens wireless headphone compatibility, and AirPlay support adds a layer of ecosystem versatility that the R6 III simply cannot match. Neither device supports aptX Adaptive or aptX Lossless, so that is not a differentiator, but the M21's extras make it the more flexible wireless performer of the two.