FiiO JM21 Review: Premium Sound in a Portable DAP

The FiiO JM21 has been one of the most anticipated releases in portable digital audio players (DAPs). With FiiO’s reputation for delivering high-quality audio gear, this device comes with high expectations. I paired it with the Letshuoer S12 IEMs for my initial testing, and what struck me first was the design. Its minimalist, lightweight metallic backplate gives it a sleek yet practical feel, which is always a good sign for a portable device. The JM21 feels like it was built with attention to detail, and that sets the tone for what’s to come.

Unboxing and First Impressions

The packaging of the JM21 reflects FiiO’s usual clean, understated style. Inside the box, you’ll find the device, a USB-C charging and data cable, a couple of protective accessories (like a screen protector or a case), and the user manual. It’s nothing overly flashy, but everything feels well thought out.

The device itself feels premium right out of the box. The metallic backplate is a standout feature, adding durability while keeping the device lightweight and portable. Ergonomically, it fits nicely in the hand, and its size makes it easy to slip into a pocket or bag without feeling cumbersome. A transparent case is welcome. And the possibility of connecting a strap to its body is promising.

Specifications:

• Processor: 8-core Qualcomm Snapdragon 680

• RAM: 3GB

• Storage: 32GB ROM (approximately 22GB usable)

• Display: 4.7-inch HD screen (750×1334 resolution)

• DAC: Dual Cirrus Logic CS43198

• Amplification: 700mW + 700mW output power

• Battery Life: Up to 12.5 hours playback (single-ended); up to 9.5 hours (balanced)

• Operating System: Android 13

Outputs:

• 3.5mm single-ended headphone jack

• 4.4mm balanced output

• USBC

• Bluetooth Version: 5.0

Bluetooth Codecs:

• Transmission: SBC, AAC, aptX, aptX HD, LHDC, LDAC

• Reception: SBC, AAC, LDAC

• Dimensions: Approximately 120.7 x 68 x 13 mm

• Weight: Approximately 156g

Design and Build Quality

The JM21 strikes a perfect balance between minimalism and functionality. Its front face is dominated by a high-resolution screen, while the back features that light metallic plate, offering both durability and elegance. The buttons are well placed and have a satisfying tactile feedback. You’ll find essentials like volume controls, a power button, and a microSD card slot—everything you need for day-to-day use.

The overall build quality is solid, and it gives you confidence that the device will stand up to regular use. It’s clear that FiiO paid attention to both form and function here.

Technical Details and Performance

The Fiio JM21 is powered by a Qualcomm Snapdragon 680 processor, an eight-core chipset running at 2.4 GHz. While the 3GB of RAM might sound a bit limited by today’s standards, for a music-focused device, it’s sufficient for smooth operation in most scenarios.

On the audio side, the JM21 shines with its DAC capabilities, delivering a clean and detailed sound. It supports high-resolution audio formats like FLAC, DSD, and WAV, making it a reliable choice for those who value lossless music playback.

Sound Performance of Fiio JM21

After pairing the JM21 with the Letshuoer S12, here’s what I found about its sound characteristics:

Bass

The bass is tight and well-controlled, with enough depth to give tracks a satisfying low-end punch. It’s not overpowering, which is great if you’re looking for a balanced sound. In genres like electronic or hip-hop, the sub-bass response adds depth without overshadowing other frequencies.

Midrange

The midrange is clean and natural, allowing vocals and instruments to stand out without sounding too forward. Vocals feel slightly laid back but maintain a sense of clarity. On acoustic and blues tracks, the separation between instruments is quite noticeable, creating a pleasant listening experience.

Treble

The treble is smooth and never harsh. It avoids the piercing highs that can cause listener fatigue, making it ideal for extended listening sessions. While it’s not the most detailed treble I’ve heard, it’s well balanced and complements the overall sound signature.

Soundstage and Imaging

The JM21 offers an impressively wide soundstage for its class. Instrument placement feels natural, and there’s a good sense of depth. However, transparency is where it falls slightly short, especially in busier, more complex tracks. It’s good, but not outstanding.

User Experience

Navigating through the JM21’s interface is straightforward and user-friendly. Menus are classic with Android 13, and settings are easy to adjust. While the touchscreen is responsive enough, the 3GB of RAM does occasionally remind you of its limitations with minor lags during heavy multitasking. Still, for its primary purpose—music playback—it performs reliably. And the swift update system is a bonus. It updated and added screen locking or unlocking after double-knocking on the screen. Familiar?

Battery Life

Battery performance is another strong suit of the JM21. In my testing, it easily lasted two days with moderate use, which is great for a portable device. For longer trips or heavy listening sessions, you won’t find yourself reaching for the charger too often.

Comparison

Testing Toto’s “Africa” with the FiiO JM21, HiBy R4, and HiBy R3 II 2025, all paired with the Letshuoer S12, revealed how each player shapes the experience in its own way. 

The FiiO JM21 stood out with its darker, warmer tone, which gave the percussion a deep and weighty presence. The expansive soundstage created an immersive sense of space, where vocals and harmonies seemed to float effortlessly. Yet, there was a slight trade-off—subtle details like delicate guitar plucks and synth lines felt a bit softened, as if peeking through a thin veil.

Switching to the HiBy R4, the focus shifted to neutrality and precision. The percussion gained speed and impact, hitting harder and tighter than the JM21, while the guitar riffs sprang to life with greater clarity and separation. The R4’s Class A amplification added a sense of vibrancy, lifting dynamic shifts with ease. However, the soundstage felt a bit more condensed. This wasn’t necessarily a downside—it brought harmonies closer, giving them focus—but it didn’t deliver the same sprawling, atmospheric quality as the JM21. Where the R4 shined, though, was in uncovering micro-details, particularly in the softer instrumental layers that might otherwise be missed.

The HiBy R3 II 2025 took a different path with its warm, relaxed tuning. Vocals were lush and intimate, standing confidently at the forefront of the mix. This worked beautifully for the emotional pull of “Africa,” but the percussion lacked the impact found in the JM21 and R4. The more compact soundstage gave the track a cozy, personal feel, which suited the vocals well but fell short of conveying the capability of the song’s arrangement. The R3 II’s saving grace is its MSEB tuning panel, which offers enough flexibility to tweak the treble and bring balance back to the mix. For listeners who prioritize smoothness and vocal richness, this might be the most appealing choice.

Pros:

• Sound Quality: Smooth and detailed sound signature with a wide soundstage and good separation.

• Build Quality: Slim and lightweight design, making it highly portable.

• Operating System: Runs on Android 13, providing a familiar and user-friendly interface.

• Output Power: Capable of delivering up to 700mW + 700mW, suitable for driving a variety of headphones

• Value for Money: Offers high-end features at an affordable price point.

Cons:

• Battery Life: Some users report that the battery life may not meet the claimed durations, especially when using power-intensive applications or higher gain settings.

• Build Materials: The chassis is primarily made of quality hard plastic, which may not feel as premium as metal constructions.

Conclusions of FiiO JM21 Review

The FiiO JM21 is a solid option for anyone looking for a portable DAP with a refined, slightly laid-back sound signature. Its build quality, wide soundstage, and comfortable listening profile make it a joy to use for extended periods. While it might not satisfy those looking for extreme transparency or cutting-edge hardware specs, it delivers a well-rounded experience that’s hard to fault.