Overview

The FiiO M21 is a 329 USD Android 13-powered digital audio player announced in 2025. Chinese company FiiO has established itself as a cost-performance leader in portable audio equipment since its founding in 2007. The M21 is positioned as an ambitious product that adopts four Cirrus Logic CS43198 DAC chips and a two-stage amplifier circuit, featuring the industry’s first desktop mode to achieve 21Vpp peak voltage and 950mW output when connected to external power. Equipped with 64GB storage, 4GB memory, and Snapdragon 680 processor, it aims to deliver desktop-level performance that transcends traditional portable audio boundaries.

Scientific Validity

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The M21’s measurement performance shows excellent results that reach transparent levels. THD+N achieves 0.0004% on 3.5mm output and 0.0003% on 4.4mm balanced output, significantly exceeding the transparent level (0.01% or below) in the reference table. The S/N ratio of 125-126dB exceeds the transparent level (105dB or above) by more than 20dB, while crosstalk maintains sufficient separation performance at 74dB (SE) and 109dB (BAL). Frequency response realizes ideal flatness with deviation of 0.02dB or less across 20Hz-20kHz, and dynamic range secures 120dB or more. Through the parallel configuration of four CS43198 DACs and two-stage amplifier design, the noise floor is suppressed extremely low at 2.1μV (SE) and 2.7μV (BAL). The 950mW output in desktop mode provides sufficient driving power even for 32Ω loads, with no measurable factors found that would hinder transparent reproduction.

Technology Level

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The M21’s technical approach is rational and contemporary. The configuration of four CS43198s in parallel drive is effective for improving S/N ratio and dynamic range, with clear theoretical basis. High-power output through external power utilization in desktop mode can be evaluated as a practical solution to avoid battery constraints. The combination of Snapdragon 680 and Android 13 provides modern usability, and the two-stage amplifier circuit design is reasonable through separation of voltage amplification and current drive. However, technical originality is limited, with the DAC chips used and circuit configuration remaining combinations of existing technologies. While the Cirrus Logic CS43198 is an excellent DAC, it’s not quite industry-leading, and the amplifier circuit is also a general op-amp-based design. Self-developed elements are few, and while the technology level exceeds industry average, it cannot be called innovative.

Cost-Performance

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In evaluating the M21’s cost-performance, comparison with the company’s JM21 is decisive. The JM21 provides nearly equivalent functionality and performance to the M21 at 199 USD, with dual CS43198 DACs, 700mW+700mW output (32Ω), THD+N 0.0006%, and S/N ratio 130dB. The cost-performance calculation for the M21 at 329 USD yields: 199 USD ÷ 329 USD = 0.605, which rounds to 0.6. The M21’s advantages are limited to RAM capacity (4GB vs 3GB), further high-power output in desktop mode, and slight S/N ratio improvement from quad DACs - hardly decisive functional differences to justify the 130 USD price gap. Major functions including Android 13, 4.4mm balanced output, MQA decode, and 32bit/768kHz support are also provided by the JM21, making practical differences limited. With products like the Hiby R4 (249 USD) also available in the market, the M21’s pricing is judged as expensive compared to products with equivalent functionality and performance.

Reliability & Support

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FiiO is an established portable audio manufacturer with 18 years of experience since its 2007 founding, maintaining a good record regarding product reliability. The M21 comes with a 1-year international warranty, which is industry-standard level. The company’s Android-powered DAP product line receives continuous firmware updates, with regular functional improvements and bug fixes implemented even for existing models. The support system is organized through authorized dealers worldwide, and appropriate repair/replacement support can be expected domestically in Japan. However, as an emerging Chinese manufacturer’s destiny, uncertainty in long-term support compared to established Western brands cannot be denied. The M21 adopts the relatively new Snapdragon 680 SoC, so firmware update support can be expected for the foreseeable future, but support beyond 5 years is not guaranteed. Overall, it can be evaluated as above industry-average reliability and support levels.

Rationality of Design Philosophy

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The M21’s design philosophy is fundamentally rational and based on scientific evidence. External power utilization through desktop mode is a practical approach to achieve high output by avoiding battery constraints of portable devices. Technical rationale is clear for S/N ratio improvement through parallel drive of four DACs and optimization of voltage/current drive through two-stage amplifier circuits. The adoption of Android 13 and Snapdragon 680 realizes dramatically improved usability compared to conventional dedicated OS-powered DAPs. The measurement performance-focused design stance is also commendable, with specifications like THD+N 0.0003% and S/N ratio 126dB that significantly exceed transparent levels being appropriate from a scientific audio evaluation perspective. However, questions remain about the necessity of existing as dedicated audio equipment. With equivalent or superior performance achievable at lower cost through smartphone + high-performance USB DAC combinations currently available, the rationality of providing a dedicated DAP at 329 USD is limited. While the design is based on scientific evidence overall, there is room for improvement from a cost-efficiency perspective.

Advice

For those considering purchasing the FiiO M21, we strongly recommend first comparing it with the company’s JM21. The JM21 provides nearly equivalent sound quality performance to the M21 at 199 USD, with limited practical differences. The M21’s unique value lies in further high-power output in desktop mode, but this is excessive specification for anyone other than users of ultra-high impedance, low-sensitivity headphones like HD800 or LCD-4. For typical IEMs or 32Ω headphones, the JM21’s 700mW output provides sufficient drive capability. For those prioritizing convenience as an Android-powered DAP, the Hiby R4 (249 USD) also becomes a strong alternative. For smartphone + high-performance USB DAC combinations, options like the iBasso DC06 Pro (119 USD) or FiiO KA17 (149 USD) provide cost advantages over the M21’s price (329 USD), though they lag in integration and convenience as dedicated DAPs. While the M21 is certainly an excellent product, its pricing is inappropriate in relation to market competition. Its value is realized only in special applications where budget allows and desktop audio compatibility is prioritized.

(2025.8.7)