FiiO JM21

Introduction

The FiiO JM21 is a compact lightweight Digital Audio Player (DAP) that combines some great features like Android 13, dual Cirrus Logic CS43198 DACs, and up to 700mW output power all at a budget-friendly price.

So, after using the JM21 for more than a month now I think I have a very good idea for its capabilities and an idea of its limitations compared to some higher end DAPs, but overall it is a great DAP in this price range.

So read on to find out more but let’s start with the unboxing:

Unboxing and Build Quality

The JM21 arrives in nice box typical of the latest FiiO/Jade Audio products: The back of the box has some specifications: Opening it up: And removing the manual you finally see the JM21 in a protective sleeve:

Taking the JM21 output of the box it has its protective sleeve already:

Here is everything you get in the box:

• JM21 DAP
• USB-C charging cable
• Pre-applied PET screen protector
• Transparent silicone protective case
• Quick start guide
• Warranty card

The packaging is clean, compact, and functional, reflecting FiiO’s experience and attention to detail.

Design and Build Quality

The FiiO JM21 is impressively slim and lightweight, making it extremely portable.

The JM21 does have a slightly cheaper / ‘plastic’ feel at least compared to much more expensive DAPs but using plastic rather than metal will keep its weight down.

The 4.7-inch HD display is sharp enough for its price, although not as bright as premium models, requiring at least 50% brightness for indoor use and 100% for outside use.

It is also much thinner than most other DAPs which also means there isn’t a lot of space for a large battery, but again this makes it much more ‘pocket-able’ DSP than most other DAPs (the Hiby R1 that I recently reviewed is more pocketable but is not Android):

With the plastic casing having a good protective case is great, so I would suggest to use it in the case immediately:

To give you an idea of the relative size here it is compared to a Retro Nano, a Hiby R1 and a FiiO M23:

Buttons and Ports

Left: Power/lock button and volume control. Right: Playback controls (play, pause, next) and microSD slot (supports up to 2TB). Bottom: Both 3.5mm single-ended, 4.4mm balanced headphone jacks, and USB-C port.

Features

Let’s get into some of the key features:

Audio Performance

With dual CS43198 DACs and SGM8262 amps, the JM21 delivers clean and powerful audio. The balanced 4.4mm output provides up to 700mW of power, enough to drive demanding headphones like the HiFiMAN HE400se or Sennheiser HD650. The 3.5mm single-ended output supports SPDIF and Line Out modes, making the JM21 a versatile source for external gear.

Smooth User Experience

Powered by the Snapdragon 680 processor, the JM21 runs smoothly with Android 13. During testing, the device showed no noticeable lag or software glitches especially after I upgraded to 1.0.5.

Android 13 UI

So as well as a newer processor the Snapdragon 680 FiiO have used a newer version of Android in this DAP than they have previous, both of these 2 decisions gives you a very snappy UI that is fast at navigation but will more than likely still seem a little slower than your smartphone UI.

But let’s get into some of the screens in this new Android 13 build, first I would suggest updating the firmware immediately as FiiO have fixed many of the battery issues that the earlier reviews mentioned.

Firmware Update

I got a system updated immediately to 1.0.4: but most of my experience for this review was using version 1.0.5, and it fixed many issues with the earlier builds especially around battery life:

Settings screens

Next let’s look at the settings menu’s and some of the key sub-menus:

Mode Choice Option

The mode choice gives you the option to switch modes:

The JM21 offers multiple modes for diverse use cases:

• Android Mode: Full functionality with streaming apps like Spotify, Apple Music, and Tidal.
• Pure Music Mode: Restricts functionality to focus on music playback.
• Bluetooth Receiver Mode: Works as a high-quality Bluetooth receiver.
• USB DAC Mode: Functions as an external DAC for PCs and phones.
• AirPlay Support: Wirelessly streams audio from iOS devices.

The Pure Music mode is really just replacing the Android launcher with the FiiO Music App, but it does stop “distractions” and lets you focus on the music, I do like this mode especially with the screen rotated, but more on the FiiO Music app later.

You get a slightly different experience switching modes options within the Pure Music Mode:

Global settings

Key options here were the Power off Timers (which greatly help with battery life) and make sure that double tap to wake is disabled (which I disabled to save battery life).

Audio Settings

There are a lot of Audio Settings to allow you to tweak the sound: And more when you scroll down:

You get SPDIF output from the LO if you want to offload an external DAC

With Bluetooth options you get an excellent set of codecs:

Battery Life

Despite its compact size, the JM21 offers decent battery life:

• Single-ended output: ~12.5 hours.
• Balanced output: ~9.5 hours.

You can also get about 7 days idle time, but I see no reason to not get the JM21 to switch off when it’s idle for a period to totally the battery life. Recharging is quick, with the USB-C port supporting fast charging.

FiiO Music

The FiiO Music application is good, but I imagine most people will use the native Music application, Spotify, Tidal, Qobuz or Apple Music but the FiiO Music application has some nice features. I have 3 other music applications that I find excellent on DAP that I will show later on but lets get into some of the FiiO Music features.

FiiO have built a few other applications, e.g. FiiO Link and Equaliser application that all work well with the Music Application:

The Lab features option has a few more options to experiment with:

For example enableing the extra Sound effect options including a stereo expander:

You can get an idea of the level of customisation available when looking at the extensive amount of audio playback in the Settings option on this screen:

The layout of the music is pretty sensible showing the music stored on the microSD card, so all the artists:

Selecting an Artist shows their albums: Then playing an Album:

The Now playing screen is nicely minimal (and can have a theme applied) and it has a nice subtle graph equaliser playing at the bottom of the screen:

You have lots of extras on the menu when playing a song like Car Mode:

And lyrics when playing you own music:

When the screen is rotated you get a nice alternative layout for the now playing screen - this time I swapped to a different Theme:

You might see the VU button next to the Song Name, clicking that shows a nice VU Meter:

VU Meters

I am a sucker for VU Meters:

And you can have dual VU Meters when you rotate the screen:

Themes

I mentioned earlier there are some alternative themes to switch too:

Screen rotation

And I like how the Application works well in landscape mode so that is an easy switch:

Equaliser Application

The now standard (and pretty good) FiiO Equalizer application is available within the FiiO Music:

Sadly for now this seems to only apply EQ to music playing within the FiiO Music App. I believe this is a restriction with the way it works with Android 13, but since its Android I did find some third party EQ applications in the Play Store here is an example of one:

Alternative system-wide EQ Application

So I used Poweramp equalizer which provided EQ for third party streaming applications (like Plexamp):

You get some customisation options for each Streaming Application inside Poweramp:

And of course you have full PEQ with import capabilities:

Alternative Music Applications

While there are probably 1000s of alternative Music Applications for Android, I thought I would highlight 3 that I use and that work very well with the JM21 (as they have easy offline storage options) for when you are not on Wifi.

PlexAmp

So as well as a subset of my music on the MicroSD card, I have a Plex server with my full collection and PlexAmp is a nice way to stream that collection remotely, but I do like that it has easy offline downloads, so I have various playlists downloaded for offline playback, very handy on an Airplane or even just out for a walk when not on a Wifi network.

There is an automatic playlist called recently added which I automatically have set for offline access - great way to listen to the latest music even if you are not on Wifi:

Roon Arc

While you can obviously run Roon on the JM21 I think Roon Arc with its “Download” capabilities is a better alternative with an even nicely UI that PlexAmp: And the offline screen:

Radio Paradise:

Another nice Streaming application with offline capabilities is Radio Paradise - I like how you can download a few hours worth of a few of the different streams. Very handy when getting on a long flight:

Sound Impressions

The FiiO JM21 delivers an enjoyable and extremely balanced sound signature. Here’s a breakdown:

Bass

• Clean and balanced with good body and texture.
• Sub-bass extension is satisfying without being exaggerated.
• Excellent control even with complex tracks like Slipknot’s “People = Sh*t”.

Midrange

• Smooth and transparent, with natural timbre.
• Vocals are rich and engaging, with no harshness in the upper mids.

Treble

• Well-extended and airy, providing a pleasant sparkle.
• Non-fatiguing and smooth, even at higher volumes.

Specifications and Measurments

The battery figures above while accurate I would definitely recommend auto switching off the JM21 when idle as the battery does drain faster than older DAP Android devices when on idle, I believe this is a mixture of the smaller battery, Android 13 and the way the Wifi works on the JM21.

That is an easy option within the settings and I set it to 10 minutes:

I was initially concerned with only 3GB of RAM compared to most Android smartphones with 8GB or more but having used it for a month I noticed no problems especially if you keep the JM21 focused on playing music and do not load all your social network applications onto it, it is not a problem.

Here are the specification for the output power:

Single-Ended (3.5mm) vs Balanced (4.4mm) Output

So that THD+N value of 0.0006% is equivalent to SINAD of 105 so not state of the art, but even my AudioScienceReview standards an excellent result but FiiO did provide a graph showing the balanced output at 30Ohms that there is slightly higher THD+N are some slightly higher frequencies with a THD+N of 0.003% which is still way below any audible noise level:

The frequency response is completely flat / neutral so other than the PEQ capabilities above the JM21 will provide the music exactly as it was recorded with no colorisation, here is again the balanced output at 30Ohms:

I found the balanced output to be excellent and on high gain I was able to drive my current hardest to drive headphones, the Modhouse Tungsten to deafening levels. I decided to measure this max output at both low and high gains for a practical measurement comparison:

If you want to utilise EQ, or maybe you like massive amounts of dynamic range you might need a little bit more power but for me the JM21 drove them perfectly at about 80% on high gain and really shows that you can probably cover 99% headphones and all IEM’s with the output power of the JM21.

Comparisons

So the reason I referenced that old fairy tale “Goldilocks and the 3 Bears” in the subtitle of this review was because as DAPs go there are smaller ones (with fewer features and less power) and larger ones which are much more expensive and are much less portable, so it seemed appropriate that the JM21 was that perfect middle ground DAP.

As an example I have both a Hiby R1 and a FiiO M23 both of which are exceptional good DAPs in their price ranges, so I thought these 2 would be good comparisons:

JM21 vs. Hiby R1

JM21:

• Larger screen easy to read with lots of Android customisations (Font sizes, Rotation etc)
• More power output Balanced output really bring out the best in the JM21.
• Android OS This is probably the biggest difference - I love the ability to have many streaming apps.

R1:

• Cheaper at less than 1/2 the price the R1 is an incredible bargain for a DAP
• System wide EQ I do love the MSEB and other audio customisations available on the R1
• No Balanced output Ultimately the R1 has limited output so fine for IEMs and easier to drive headphones but don’t expect miracles

For me this comes down to a few questions to ask yourself:

1. What are you going to use the DAP with? IEMs or Headphones?
2. Streaming or your own Music? R1 has some streaming options (Tidal, Qobuz) but not nearly the same as the JM21.

JM21 vs. FiiO M23

JM21:

• Affordable Price Point: At $199 USD, the JM21 offers exceptional value for its features. 
• Compact and Lightweight: Weighing just 165 grams, it’s truly pocket-sized, making it an ideal travel companion. 
• Latest Android OS: Runs on Android 13, ensuring compatibility with modern apps and a smooth user experience. 
• Less Internal Storage: Comes with 32GB of internal storage compared to 64GB on the M23 

M23:

• Large Size: Fairly large form factor and larger screen. 
• Robust Build Quality: Beautifully constructed with a premium feel, enhancing durability and aesthetics. 
• Superior Audio Performance: Features flagship AKM DACs and THX AAA 78+ amplification, delivering powerful and neutral sound.
• Some Extra Features: You get some extra features like system-wide EQ and desktop mode with super high gain.

The fact that the JM21 at 1/4 of the price is able to compete with the M23 shows what an incredible bargain it is, but again it comes down to a few questions you might want to ask yourself:

1. How much power do you need? The M23 has the edge
2. Is a larger battery more important than portability

Rating

I had to give the JM21 a 5-star pragmatic rating, it has the power, the lightweight portability and almost all the features you could want all for less than $200. I would love a future firmware update to provides FiiO EQ system-wide but as I showed earlier there are third party PEQ applications that can mostly provide that capability.

The only other thing possible to be concerned about would be battery life but with the latest firmware this has not been a problem especially since I enable the idle shutdown.

Conclusion

The FiiO JM21 sets a new benchmark for budget Android DAPs. At under $200, it offers a level of performance and versatility that’s hard to beat. Whether you’re streaming music, using it as a USB DAC, or simply enjoying your local files, the JM21 delivers a smooth and enjoyable listening experience.

While it has some minor drawbacks, a smaller battery and no system-wide PEQ functionality, these are forgivable at this price point. The JM21 is a “Goldilocks DAP”, striking a perfect balance between portability, power, and features.

Highly recommended for anyone looking for an affordable yet capable Android DAP.