FiiO M23

FiiO M23 :: Portable Audio Player :: $699 (Dark Blue Aluminum Model) & $899 (Silver Stainless Steel Model)

-

This review was prepared using a M23 borrowed from FiiO's authorized distributor in South Korea, 'Scheherazade'.
I was commissioned to provide an honest opinion in a free and independent manner, without any external influence.

Btw, are you more familiar with Korean?
So am I, and If that's the case, I think you'd be better off reading my review written in Korean here.

-

Founded in 2007 by former OPPO employees, FiiO has been in the audio business for nearly 17 years, producing a wide range of products since its establishment in 2007. The DAC/AMP family has been highly acclaimed and popular around the world, contributing to the “Chi-Fi” trend.

The FiiO M23, which I will introduce today, is the Fifth generation of the FiiO's DAPDigital Audio Player lineup. (X7 - X7II - M11PRO - M11PLUS - M23)

Unlike smartphones, DAPs have a long release cycle, and if you look back at this history, you'll see that it's a lineage that spans a whopping 9 years. This gives you an idea of how long FiiO has been making DAPs.

-



You're now looking at the package of FiiO M23.
If you lift out the card with a brief description of Desktop Mode, and you'll find the M23 inside a hard foam.

The back of the package has a short list of specs, which I've summarized in the table below for ease of reading.





The internal components include :

• FiiO M23
• Display Protective Glass (Pre-installed)
• Transparent TPU Case (for Aluminum Models)
• USB C to C cable
• USB A to C adapter
• SD Card Tray remover pin
• User manuals

The M23 Aluminum Model comes with a transparent TPU case, while the slightly more expensive Stainless Steel Model comes with a leather case.

Given that the DAP products are notoriously hard to get cases for them, it's nice to be able to protect your device right out of the box, and I'm particularly pleased with how well the case fits together despite its sharp angles and complex shapes.

That said, I do have to admit that the TPU material is far from luxurious, and the jelly case is subject to yellowing after prolonged exposure to UV light due to the nature of the material. It would have been nice to see a leather case included with the aluminum model as well.



The FiiO M23 has a cold frame that's cut and machined from solid metal, with tempered glass on the front and back. In many ways, it's a premium design that's reminiscent of a flagship smartphones, and its solidity and weight in the hand is quite appealing.

The design could be boring, but the sharply angled hexagonal edges and the unique pattern of the tempered glass on the back that splits the light into multiple lines add a unique touch to the design.

You'll also recognize the Hi-Res logo engraved on the back.



Let's take a look at the right side of the device first.

From the top, you can see the “Back / Pause / Forward” buttons lined up in a row, with the 'Desktop Mode Switch' and the 'Hold Switch' underneath.

The 'Hold Switch' can be flipped up to lock any of the buttons out of action - except for the power button. You can still press the power button to turn on the screen, but you're completely prevented from touching the screen. Depending on your preference, you can allow certain buttons to work while the hold switch is flipped.

The 'Desktop Mode Switch' literally toggles the 'desktop mode' on and off, which is something FiiO has been pushing hard lately, and you'll notice a big performance boost from it. We'll discuss this in more detail later.



On the left side of the device, you'll find the power button, volume touch panel, and multifunction buttons. There's a colorful LED surrounding the power button that changes color depending on the quality of the music you're listening to.

The unique volume touch panel, which looks like covered with a carbon fiber, is designed to recognize your touch, allowing you to quickly adjust the volume by simply swiping your finger up and down.

It's a bit of a miss as it doesn't have the same feedback at your fingertips as a volume knob with a clicky snag, but I like the durability advantage of having no moving parts, and you can still fine-tune the volume by clicking on the touch panel just like you would do with a regular volume button.

Below the volume touch panel is a multifunction button. You can personalize what this button does in the Settings app, assigning it a role like changing the equalizer and filters, or switching to Bluetooth reception mode. I have set mine to switch to USB DAC mode, which I personally find really handy.



The top of the product features a 3.5mm single-ended terminal and a 4.4mm balanced terminal.

Both headphone sockets are designed to double as lineouts, and the 3.5mm socket is also capable of outputting coaxial digital signals via SPDIF mode. If you can find the right cable, you can even use the M23 to connect to an external DAC.

With so many functions integrated into a single socket, it's important that it's durable enough to withstand frequent cable swapping. To that end, FiiO says that they designed the sockets to be stronger and more robust, with separate metal components on all sockets, including the USB-C.



If you look at the bottom of the product, you'll see two USB-C sockets and an SD card slot.

The SD card tray pops out when you poke the hole with the included pin, which is supposedly capable of recognizing SD cards up to 2TB. DAPs don't usually have fast internal storage, so I'd recommend using an SD card to store your music.

The USB-C port in the center is a USB 3.0 port that can transfer data and charge at the same time. When connecting to other source devices, you'll need to use the center port to transfer data back and forth.

Next to it, the USB-C port with the orange accent is purely for power delivery. It's essential for 'Desktop Mode' technology, which maximizes acoustic performance by drawing 100% of its power from an external source instead of a battery that's sensitive to charge and discharge.

Because this port is designed to deliver higher capacity power more reliably, it's also said to be able to charge batteries at a slightly faster rate than the center Data & Power port.



FiiO has a long history of building DAPs, nearly 11 years in fact.

In 2015, just two years after introducing its first DAP product, FiiO introduced its first full Android DAP - X7, showing its pioneering response to the streaming services at a very early stage, and I think I don't need to emphasize the technology and know-how that FiiO has accumulated over the past nine years of Android DAP development.

Perhaps as a result of this, the FiiO M23 was quite pleasant to use and sounded great. Even though it's positioned in the mid-range position, I didn't notice any major gripes or shortcomings throughout my time with it that I wouldn't envy a higher-end products.

The Snapdragon 660 SoC used in the M23 is not the latest chipset to be produced, but it is more than capable of playing high-resolution music. Being a Qualcomm chipset - although there aren't a lot of products that support it - but the aptX HD codec is available, which is a plus.



The Android OS is well optimized, and third-party apps run smoothly and reliably. It comes with the Google Play Store installed by default, so it's easy to install all the apps you're used to using on your smartphone without having to do anything special.

I was able to install YouTube and other video apps, and the quality of the 5.5-inch display with an 18:9 ratio is pretty good, except for the fact that the maximum brightness is a bit on the dim side. I can say it was quite good for watching videos on it. Of course, it doesn't support DRM like Widevine, so if you want to watch videos properly, you should use the M23 as a DAC.

The Android OS version is 10, which is a bit on the low side, but it's still a version that can utilize almost all streaming platforms, which is fine for the purpose of a DAP that plays music, but it's also true that you'll start to worry about applications being unsupported.

Luckily, FiiO is working on an Android 12 update for the M23. It's a bit behind schedule due to the simultaneous update for multiple models, including the M11S, but FiiO has expressed its strong commitment to providing a stable A12 update, even if it's a bit late, in various communities and forums.



With its multiple Modes, the M23 is more than just an audio player; it can also act as a high-performance DAP/Amp by connecting to a variety of source devices.

With this feature, you can watch a movie on a large TV in your living room and listen to the sound through the M23 at the same time.

The M23 supports a total of five connection modes, each of which is characterized by the following features

• Android Mode : The default mode. Uses the M23's Android operating system.
• Pure Music Mode : Focused on offline music listening via the FiiO Music app.
• USB DAC Mode : Allows M23 to be utilized as a USB DAC.
• Bluetooth Receiver Mode : Enables M23 to be utilized as a Bluetooth receiving DAC.
• Airplay Mode : Enables the M23 to be utilized as an Airplay listening DAC.

Airplay Mode is particularly useful for Apple device users.

Unlike regular Bluetooth, AirPlay works over a local network (LAN) via WiFi, which means it can reliably transmit lossless sound over a much wider bandwidth, making it a far superior wireless connection in terms of sound quality.

There's no need to go through a complicated pairing process, and once the M23 is in Airplay mode, connecting is as simple as clicking a button or two on your iPhone.

It's also worth noting that, although not shown in the menu above, the M23 is Roon Ready, supporting Roon connectivity via the pre-installed FiiO Roon app.



The usability features don't stop there.

The M23 has the ability to connect with smartphones on the same network via the FiiO Cast app, which goes beyond just sending and receiving sound signals and allows you to control all of the M23's features from your smartphone.

You can adjust the volume, pause, flip through songs, switch connection modes, change device settings, open offline music lists stored on your M23 to play your favorite songs, and even mirror your M23's screen to your smartphone for remote control.

I think this feature is a result of the fact that DAPs have leveled up in sound performance in many ways, and more and more people are using them as a single main setup.

Since DAP products are generally not light in weight, the ability to switch music from a smartphone, which is much lighter than a DAP, was a feature that I utilized more often than I expected.



As well as the ease of use we've discussed, you'll notice that a lot of effort has gone into the acoustic technologies that are directly related to the audio experience.

The system-wide equalizer is one of the best examples of this. By default, it acts like the 10-band equalizer most people are familiar with, but it also functions as a parametric EQ that allows you to personalize the frequency, filter type, and Q value by long-pressing each band, making it a great equalizer for beginners and advanced users alike.

The Sound Effects tab lets you change your tone in a more intuitive way. In addition to increasing and decreasing bass and treble, you can also make fun timbral changes, including stereo enhancements.

In addition to this, the Audio section of the Settings app also allows you to assign Line Out / Headphone Out / SPDIF roles to each audio socket, or change the kind of digital filters that the DAC uses when processing your audio.



The story that “the Android OS structurally forces the sample rate of the audio it plays to be converted” has become so common knowledge that most audiophiles are now aware of it, which is why certain applications that purport to achieve 'Bit Perfect' have become must-have apps among enthusiasts.

However, application-based “bit-perfect solutions” have a fatal flaw: they are structurally incapable of affecting the sound played in other applications, so you must listen to offline music through those applications.

For DAP makers that have adopted the Android OS, how well they've implemented this “system-wide bit-perfect” is often used as a measure of their software design capabilities: if it's not done well enough, several issues can happen - like certain apps thinking that your device is rooted.

In that regard, the DAPSDigital Audio Purification System, a lossless music processing system that FiiO emphasizes, is quite remarkable.

DAPS refers to an entire software system customized to ensure that audio signals are reproduced as pristinely as possible from the kernel and HAL levels, which are closest to the hardware, including the DAC chipset, and is difficult to implement without a high level of technical understanding of both hardware and the Android OS.

The M23 has an LED on the power button and a sampling rate on the top bar to indicate the quality of the audio currently being played, and while I tested a wide variety of applications and streaming services, I didn't notice any resampling of the sound source. In many ways, I would say that the software is very well done, just like any other FiiO products.



The FiiO M23 features AKM's latest DAC. Unlike other products that integrate all functions in one chipset, this is a two-chip solution. The AK4191EQ and AK4499EX, fulfills different roles.

The design of the chipsets that handle digital signals and those that handle analog signals is strictly separated on a chipset-by-chipset basis, which has the advantage of increasing noise resistance.

However, it also has the disadvantage of occupying a larger area on the board because the chipset is divided into two. therefore, it has been adopted mainly for desktop D/A products that are relatively free from space constraints.



The amplifier to support the high-performance DAC is the THX AAA-78+. This amplifier consumes about 1.7 times more power than the THX AAA-38 in the diagram above, but offers a significant increase in power output with slightly better sonic performance.

As a result, the M23's output characteristics are quite exceptional. The output is generous enough to drive IEMs, dynamic driver headphones, and you can even drive some planar headphones if you utilize the balanced output.





The M23 has plenty of power as it is, but the “Desktop Mode” that FiiO has been pushing hard lately can take its performance to extreme limits outside the constraints of a portable device.

'Desktop Mode' is all about squeezing the most out of your acoustic performance from a stable, externally supplied power source. Since lithium-ion based batteries suffer from significantly reduced battery life when used at too high of a power level, there is a limit to the maximum power that can be realized from a portable device, and this can help you get the most sonic performance out of your device without worrying about battery degradation.

Using 'Desktop Mode' on your M23 is simple. Simply flip up the D.MODE switch on the right side of your device, connect your M23 to a fast charger that supports USB PD technology, and you'll see a notification asking you to enable 'Super High Gain', as shown in the photo above.

Even if you accidentally close the notification, you can select 'Super High Gain Mode' again from the Gain settings, which are visible when you pull down the top notification bar.

Once you've selected 'Super High Gain', you'll notice that the M23's already high output is now up to four times higher, reaching up to 1000mW in certain situations.





Contrary to popular belief, high impedance does not necessarily mean it's difficult to drive. The truly difficult headphones to drive are the low-impedance, low-sensitivity headphones, most notably Hifiman's Susvara.

The Susvara has an impedance of 60ohms and a sensitivity of 83dB/mW, which is exactly what you'd expect from a low-sensitivity, low-impedance headphone, but if you take this information and turn the headphone loudness up to a generous 110dB, you'll see that it requires over 500mW of power.

That's a lot of power for most portable gear, especially DAPs, but the FiiO M23's 'Desktop Mode' should be able to handle it without frustration. Of course, you'll need to get an XLR to 4.4mm adapter or a separate 4.4mm balanced cable.




Now let's listen to the sound of M23.

The FiiO M23s were able to drive all of my headphones with ease and without any signs of struggle. While I tend to stick to less challenging headphones, I'm not sure there's anything the M23 can't drive unless it's a headphone with a really unusual design, as we've seen.

With so much power, the M23 never felt like it was lacking while listening to music on my headphones, even with the gain on low. Even then, I was able to focus on the sound in a very quiet background without any noise, even when matched with very sensitive earphones at 115dB/mW.

It's quite impressive to see it handle such a wide spectrum of products, from the most sensitive to the most difficult to drive headphones, and still be able to neutrally reproduce the sound without any significant distortion or coloration.

In many ways, the FiiO M23 was true to its role as a HiFi DAP - to reproduce the original sound without distortion - and the performance numbers on the spec sheet were a good indication of that.


L - Super high gain mode, full volume playback -6dB sinusoidal signal, 20Hz-80kHz, SE headphone out (32Ω load)
R - Super high gain mode, full volume playback -8dB sinusoidal signal, 20Hz-80kHz, BAL headphone out (32Ω load)

FiiO is one of the rare companies that publishes the measurements of their products on their website, and the M23 is no exception.

In the first set of measurements, you can see the frequency response of the M23.

It shows a perfect reproduction of the signal from 20Hz to 20,000Hz, the human audible frequency range, with no significant roll-off. It's not until we get to 80kHz, well outside the human audible range, that we observe a slight roll-off, which is very good.


L - PO Super High Gain Mode 2V@32Ω
R - BAL PO Super High Gain Mode 4V@32Ω

Distortion performance is also very good.

Both the single-ended unbalanced and balanced terminals, even when operating at their peak performance, show excellent numbers in metrics including THD+N and SINAD. This can be interpreted as having ultra-low noise characteristics that are difficult for the human ear to perceive.

-

So far, we've taken a look at FiiO's new mid/high-range DAP, the M23.

If you look at FiiO's DAP lineage, which has recently undergone a change in product naming conventions, you'll see that the M23 is the second tier in a four-tiered lineup, behind the upcoming M21. Above it are the M15s, and the M27, which is the replacement for the M17 in the works.

So FiiO has been describing the M23 as being in the “mid/high-range line,” and I couldn't help but think, “Is this really a mid-range product?” when I was using the M23.

It's hard to see how they could do any better than the M23, which has already shown that it's hard to complain about its audio performance, output power, and technical perfection. Of course, I'm aware that the higher-end M17 is already armed with a ton of outputs, a larger battery, and more, but for most enthusiasts, the M23 is more than enough to get you started on the road to end-game DAP.

If you're looking for a full Android DAP with serious performance, but with a modest weight and size that allows for some portability, the FiiO M23 is definitely worthy of consideration.

FiiO M23 Technical highlights

FiiO M23 is a new mid-range DAP, the successor of the much acclaimed FiiO M11 Plus ESS. As you may well remember, the M11 Plus was originally launched with dual AKM AK4497EQ DAC chips but after the devastating AKM factory fire, FiiO has switched production to dual ES9068AS chips. For the M23, FiiO has returned back to AKM and the new device utilizes the flagship AK4191EQ + AK4499EX combo. This DAC chip is a new design that totally separates the digital and analog portions and also features the “DWA ROUTING Technology” to further improve the signal-to-noise ratio. FiiO has already adopted this DAC chip combination in their portable DAC/amp, the Q15 and the FiiO K9 AKM desktop DAC/amp.

The THX AAA 78 headphone amplifiers, that were used in the M11 Plus and M11 Pro, have been upgraded to the much better THX AAA 78+ amplifier architecture that allows for greater power output with higher fidelity. The M23 uses two of them in a fully balanced configuration.

The audio architecture consists of DAC, I/V, LPF, voltage amplification, and parallel amplification stages. Responsible for handling the I/V and LPF stages are 2 low-noise and high-precision OPA1612 op-amps. The voltage amplification is taken care of by 2 low-noise and high-bandwidth OPA1662 op-amps.

A large number of high quality parts, like high precision film resistors, Panasonic film capacitors and high capacity polymer capacitors, are used in the audio circuit.

A 4-stage 20-rail power supply with independent analog and digital supplies is used to provide clean and stable power to the M23.

The player supports local decoding up to 384kHz/32bit PCM and DSD256, USB DAC decoding up to 384kHz/32bit and DSD256, and USB Audio up to 768kHz/32bit and DSD512. All modes support full MQA decoding.

You can read more about the
FiiO M23 here.



Desktop mode with dual Type-C ports

The M23 is FiiO's first portable player with dual type-C ports, one of which is dedicated to accepting power only (POWER IN). When this dedicated power type-C port is connected to a fast charger, the Super High Gain Mode can be activated for more gain and more output power. In this mode, the output power can reach up to 1000mW/32Ω per channel. While in this mode, the other Type-C port does not consume any power and thus makes it suitable to connect the M23 to a phone for use as a USB DAC.

The M23 also features FiiO’s Desktop mode with a dedicated switch. When this mode is activated, the M23 is completely powered by an external power source. The built-in battery will neither be charged nor discharged, which ensures the M23 can be used as desktop equipment without fear of damaging the battery. In order to activate this mode you must connect a fast USB charger (or any other 5V DC power supply) to the power type-C port and toggle the Desktop mode switch. The Desktop mode will also unlock the Super High Gain Mode for higher power output.

The Battery

The FiiO M23 features a large, 5500mAh capacity battery that supports a dual-mode, fast-charging system that utilizes extreme fast-charging + normal fast charging. At a lower battery state of charge, extreme fast-charging is used to safely allow for up to 30W charging speeds. When the battery gets close to a full state of charge, the M23 switches to slightly slower normal fast-charging, which allows for greatly improved charging times while still maintaining battery health. Battery last time is about 8-9 hours from the balanced output at high gain mode, steaming high resolution material from Qobuz.



Other features

The player features a low-jitter clock and a HiFi audio core that bypasses the original Android version preserving the original sampling rate of the audio stream (both PCM and DSD). A 10-band PEQ with FiiO's proprietary tuning algorithm can be used in any operating mode. You can adjust the EQ's frequency points, gain, bandwidth, and Q value to fine tune the sound. Additionally you activate FiiO's ALL TO DSD function in any operating mode. I don't equalize so I haven't fiddled too much with the PEQ and can't offer further insight.

The M23 supports six different operating modes: Roon Ready, Android, Pure Music, Bluetooth, and AirPlay. You can also stream music over DLNA by retrieving music from NAS, local networks, and cloud servers through UPNP/SMB.

Bluetooth connectivity is also supported with the SBC/AAC/aptX/aptX HD/ LHDC/LDAC codecs during transmission and SBC/AAC/LDAC during reception. The wireless connection is strong and stable while the audio quality is as good as it can get from Bluetooth’s lossy protocol.

Non Audio stuff

The chassis of the M23 features FiiO's classic, hexagonal honeycomb design with its distinctive edges that give it a rather industrial look. While I am a big fan of FiiO's M15S rounded design, I can see many people preferring the M23 for its more modern and futuristic appearance.

The chassis of the deep blue version is made from solid aluminum alloy and all ports on the player are reinforced with specially designed metal pieces. The back is reinforced with an electroplated tempered glass panel. Build quality and finish are simply excellent while the M23 is also available in a stainless steel version which looks even more premium and luxurious.

UI and connectivity

The FiiO M23 has a 5.5” touch panel with vibrant and crisp colors that is fast and responsive. The size of the player (75.7x136.5x18.1mm) makes it suitable for one hand use. The M23 is not as compact or lightweight as the iBasso DX170 or the Shanling M3 ultra but it is still a portable player that you can carry around with you and it has the benefit of the desktop mode that the players don't have.

The M23 also has hardware buttons for easier operation. The right side houses three buttons for playback control, the Desktop mode toggle switch and a hold switch. At the left side of the unit we have the power on/off button, the innovative volume touch panel and a multifunction button that is user configurable. There are various functions that can be assigned to this button, like switch digital filters or enter USB DAC mode etc. You can adjust the volume level of the audio by either using the touch slide function or more traditionally by pressing the up and down edges of the touch panel.

The bottom of the chassis houses the two USB type-C ports and a micro SD card slot that accepts SD cards up to 2TB. At the top of the chassis you will find the two headphone outputs, 4.4mm balanced and 3.5mm single ended. Both can be configured as line outputs with a fixed or variable level while the 3.5mm also doubles as a coaxial output.



Performance

At the heart of the FiiO M23 is a Snapdragon 660 SoC with 4GB of RAM that ensures a snappy operation and smooth user experience. The player is fast and responsive, you can browse and listen to music at the same time without experiencing any lagging. The M23 supports the familiar Android interface and gestures while you can download all your favorite applications from the Google play store which comes pre-installed.

The system runs the Android 10 OS which is outdated by modern standards but the truth is that I didn't find anything missing while using the player for music listening. I don't use my DAPs for gaming or any other applications so I don't much care about the Android version as long as it is compatible with my favorite music apps. However, since Android 10 is no longer supported, I do believe that the M23 should have come with a more recent Android version.

For the purists who like to experience the best possible sound quality there is the option to switch operation to the pure music mode which kills all unnecessary tasks and runs the FiiO music player which incorporates many functions and allows for deep audio customization.

Upcoming Android update

As for writing these lines, FiiO is working on a new firmware that is going to update the M23 to Android 12. The update will be released in about a month so stay tuned.

Accessories

The included accessories are a screen protective film (pre-installed), a silicone protective case (for the Aluminum Alloy Version), a leather case (for Stainless Steel Version), a USB-A male to Type-C female adapter and a type-C to C data/charging cable plus some paperwork. It seems that FiiO is cutting down costs because the M11 Plus ESS included the leather case as a standard.



Power output

The FiiO M23 has decent power output even without enabling the desktop mode as it can do 475mWpc/32Ω or 630mWpc/16Ω from the balanced output. The Desktop mode raises the power to 1Wpc/32Ω from the balanced output, enough to run most headphones except some really difficult ones. The FiiO M23 supports four gain levels for better matching with various loads and is absolutely silent when used with very sensitive earphones like the FiiO FX15.

I have used various headphones, from the FiiO FT5, to the Sennheiser HD660S2 and the HIFIMAN Arya Organic with very satisfying results. The M23 has plenty of power to drive them with confidence, strong grip and great dynamic range. As per usual practice, the FiiO M23 was left playing music for about 100 hours before listening evaluation.

The HiFi boost mode

The recent 1.0.1 firmware update has introduced a number of new features and sound tweaks but the most important of them is the HiFi boost mode which provides higher power output in battery mode. The HiFi boost mode can be enabled from the audio settings and will raise the power output under battery mode from 475mW/32Ω to a whole 760mW/32Ω thus making the M23 much more powerful but still not class leading. There are a couple of competitive DAPs that are more powerful than the M23, like the Shanling M5 Ultra ($589) that can do 1.1W/32Ω without the need of an external power adapter.

Going back to the FiiO M23, the HiFi boost mode can drive a lot of full sized headphones with the downside that it will increase battery consumption and heat generation. However, under real working conditions, like driving the HIFIMAN HE1000 SE, I didn't notice any significant temperature rise or battery drainage.

Audio Stuff

(The text includes comparisons with the FiiO M11 Plus ESS and AKM plus the FiiO K9 AKM)

The FiiO M23 has stunning audio performance without anything really negative worth noting. The sound is a nice combination of musical timbre with stellar technicalities that synergize in harmony to make for a captivating and lifelike listening experience. The overall sound signature of the FiiO M23 reminds a lot of the FiiO K9 AKM, it is literally the portable version of FiiO's much acclaimed desktop DAC/amp which happens to be one of my favorites. Tonally balanced and very cohesive, this is the kind of audio player that can match with all kinds of headphones and handle various music styles. Rest assured that the FiiO M23 will pay due respect to all your headphones and is not going to mess with their frequency response and tuning.

This is a neutral sounding DAP with a touch of warmth and natural timbre, far more musical and engaging than the M11 Plus ESS. Technically competitive and very transparent, the M23 offers great fidelity and precision but not at the expense of musicality. The previous ESS version was a little more technically proficient and clean but also a touch more clinical and sterile than the M23 which is also much improved when compared with the legendary M11 Plus AKM which used to be my favorite DAP back at the time.

The following sections might sound like I am copying my FiiO K9 AKM review but this is something I can't help avoiding because these two devices have similar sound performance, especially when you enable the desktop mode of the FiiO M23.

The FiiO M23 produces deep bass that is fast, tight and controlled with remarkable clarity, layering and definition. It is dynamic and impactful albeit a little bit lean and dry on its textures. This is a THX module limiting factor, the FiiO M15S or some other players can produce more weighty and visceral bass but the M23 is still good and better than the M11 Plus ESS in this regard. The FiiO K9 AKM incorporates a beefier power supply and better THX modules and as such it can produce greater dynamic swings and more generous physical impact but the M23 is not that lacking, especially when you enable the desktop or the HiFi boost modes.



The AKM DAC chip that is used in the M23, is a much better match for the THX modules than similar ESS chips because it helps mitigate their academic sterility. They synergize far better to produce a sound full of natural timbre and diverse harmonies. This is something that gets perfectly clear when focusing on the mid-range of the M23, which is colorful, captivating and engaging. The timbre is realistic and more organic than it was in the M11 Plus ESS. More analog sound but at the same time without loss of clarity, separation and articulation. The FiiO M23 is very resolving throughout the whole frequency range, far surpassing what is expected for the category. It is not as refined and resolving as the FiiO M15S or the M17 but not that far behind and it comes at a much lower price.

The FiiO M23 is fast, faster than the M15S and as energetic and sparkling as the M17 but also smoother and more polite. The treble is crystal clear and extended, transparent and well defined but not bright or sharp. The M23 far surpasses the M11 Plus ESS in treble smoothness, timbre realism and lack of significant artificiality while it is equally resolving and refined with deep detail retrieval without sounding analytical or boring.

The soundstage is open and spacious with excellent positioning accuracy and solid stereo image. Depth layering is also very satisfying and the player sounds grand and immersive but the THX modules are somewhat limiting the sense of atmosphere, they are not that good in communicating time and space information. Still, the M23 will make your favorite headphones sound grand and help them handle the most demanding large scale symphonic and choral works.



Vs the iBasso DX260

The $250 more expensive iBasso DX260 ($950) is the first player to utilize an octa-DAC chip matrix, a groundbreaking design that utilizes eight CS43198 flagship DAC chips, with four of them dedicated to each channel. SoC and RAM are the same in both players but the DX260 runs a newest Android 11 version. The iBasso DX260 is also the first player with a user replaceable battery but on the other hand, it doesn't have the unique desktop mode of the FiiO M23. Despite that, it is very powerful with 1015mWpc/32Ω without the need of an external power adapter. However, there is no way to bypass the internal battery in a pure desktop working situation. Screen size is 5”, slightly smaller than the 5.5” of the M23 but in exchange you get a player that is slightly more compact and lightweight.

The iBasso DX260 is the most transparent and neutral sounding DAP on the planet with remarkable clarity, layering and separation. It offers masterclass technicalities while still sounding natural, musical and engaging. The FiiO M23 can't match the technical performance and the class leading transparency of the DX260 but it offers a different kind of sound shaping that many people will prefer. The low-end is more visceral and weighty, it sounds fuller and hits harder. The overall timbre is more organic and analog, the temperature of the sound is warmer. The treble is smoother, a little laid back, more polite and less energetic. Imaging, separation and layering are very strong on the DX260 but the M23 sounds a little more expanded and holographic.

Conclusion

The FiiO M23 is not only a much improved version of the M11 Plus ESS but undoubtedly one of the finest sounding audio players without any significant drawbacks. It can easily be considered as one of the best DAPs just judging from the sound quality, let alone the unique desktop mode and the dual USB type-C ports. The FiiO M23 combines stellar audio performance with many features in a combo that is very hard to beat at this price point. And while it might not be a flagship killer, the FiiO M23 offers near flagship level performance at a very affordable price thus making it a best buy recommendation.

The review sample was kindly provided free of charge. The price of the FiiO M23 is $699 and you can buy from here.

The FiiO M23 is also available at FiiO's Amazon shop.

General/Build/Packaging
Fiio needs no further introduction. I have tested and reviewed several products from the brand and I have good experience with their products in general. I have their latest DAP with me today, the Fiio M23 which houses AK’s flagship DAC, the 4191+4499EX paired with a fully balanced THX AAA 78+ headphone amplifier as well as a plethora of components within the unit itself.
The build quality is very solid and premium looking, no sharp edges, the volume can be adjusted via the touch panel or physically as well. A 3.5mm and 4.4mm output are located on top of the player, lineout is shared and switchable via the OS itself.



Specifications (Full Specs here)

• CPU: Qualcomm Snapdragon 660
• RAM: 4Gb LPDDR5
• Rom: 64 Gb (4Gb for the system)
• DAC: 1x AK4191EQ + AK4499EX
• Amp: 4-Way THX AAA-78+
• Sample rate : PCM : 8Hz – 384Hz (8/16/24/32bits) native – DSD64/128/256/512
• System clock: Full synchronization technology with 4th Gen FPGA processor and dual Japanese crystal clock
• Outputs: 3.5mm TRS // 4.4mm Pentaconn // USB-C
• Input: USB-C
• Screen: 5.5″ 1440×720 IPS Screen
• Micro SD: SDHC / SDXC (single slot)
• WiFi: 2.4 GHz / 5 GHz support
• Streaming supported directly – Full Google Play Support
• Bluetooth support: SBC, apt-X, apt-X HD, LDAC, HWA, (AAC receive only)
• Duplex Bluetooth: the player can emit and receive music
• Battery: 3.8V 5000mAh Li-Polymer
• Quick Charge: QC4.0, PD3.0
• Battery life: 10.5h with wired headphones (3.5mm), 9h with a Balanced headphone
• Charging time: around 3.5h
• Size : 136,5 x 75,7 x18.1 mmWeight: 299g

IEMs/Headphones/Equipments used for this review

• Sony MV1
• Spirit Torino Twin Pulse IEM
• Letshuoer EJ09
• Fiio FT3

Foreword
My review is solely based on what I hear via my equipment and I never consider my reviews to be objective in any way rather a subjective approach. Do take into consideration that everyone’s ear anatomy is not the same, so the psychoacoustics perception might be different as well, but i believe it will not stray too far

General Features (Battery Life, UI/UX)

• Battery life largely depending on the volume and gain setting, as well as file format, on balanced output, using FT3 and volume level at 60/120, High gain, streaming Tidal, i am getting roughly 7-8 hours of battery life, on SE with similar gain and volume level, i gain an additional hour +- (this is a very subjective observation, no exact measurement done, hence please don’t view this objectively, rather a reference)
• UI/UX is generally very good for me, the OS is very fluid and i encounter no lag/sluggish when scrolling through lots of titles in the Fiio Music Player as well as Tidal, Apple Music
• Desktop mode enables you to run solely from the power source and will not drain the battery, however, when you use the M23 with any PD enabled charger, it will enable the super high gain mode
• Wireless connectivity ( Wifi, Bluetooth) they are generally quite stable and i did not experience any disconnection from the Wifi nor Bluetooth (except when it is out of range for bluetooth)

Sound Impression (Slow Filter, High Gain Firmware 1.01)
The M23 has been run in for approximately 50 hours prior to writing this impression. The sound of the M23 is nothing but amazing, despite sharing the same DAC configuration as Q15 as well as K9 AKM which i have tested and reviewed, they sound nothing alike, which shows that having the same DAC doesn’t mean they will sound the same, it’s the implementation of the amplification as well as the circuit design that matters. I’m not saying it will make a bad sounding/ badly tuned IEM turn good, it simply makes what is already good a step further and eeking out every bit of hidden potential your IEM/headphone have. The M23 is quite neutral to my ears if you’re using the Fast Filter, i prefer it to be slightly coloured hence i’m using the Slow Filter as stated, there’s a slight lift on the lows, but the overall listening impression to me is that it is natural and the technicalities are very impressive.
Soundstage is largely dependent on the transducers and mastering of the songs, but M23 does render the soundstage very open and let you have a good perception on the stage size in terms of depth, width and height.
Imaging is absolutely excellent with very good separation and layering, instruments can be pinpointed easily and they sound like they each have a space of their own and not mushed together. With desktop mode on, and plugged into a fast PD charger/power bank, and enabling the super high gain mode, things have been taken up a notch, good dynamics as well as slightly better control in terms of the lows and also soundstage.

Pairings
Letshuoer EJ09

• EJ09’s sound profile by nature is boosted sub bass with analytical sound, note weight is borderline thin
• Pairing the EJ09 with the M23 is nothing but fun, the bass is slightly elevated, it has more punch now and better extension, it is tight and the texture is good as well, all these without messing with the mids and highs, this is evident when listening to Gojira’s Amazonia, the double paddle especially has more punch
• The mids are slightly forward and doesn’t sound that recessed
• The treble is slightly smoother, the imaging and detail retrieval is just amazing, i can definitely hear the notes that i need to focus more previously in order to hear it, the M23 renders it with ease, Hans Zimmer’s Why So Serious ( The Dark Knight )
• Soundstage has more width and depth, doesn’t sound that 2D anymore
• Note weight is slightly thicker and more musical overall, suitable for those who find the EJ09 a tad bright

Spirit Torino Twin Pulse IEM

• The Twin Pulse is neutral with slight warmth on its own, based on my listening impression pairing it with M23, the soundstage is definitely “bigger” than before, especially on Super High Gain mode, Twin Pulse IEM scales really well with more power, imaging that is already good has been taken a step further with excellent separation as well as layering, simply amazing
• Bass sounds slightly thicker but not slow by all means, the rendered texture is also improved
• Not much changes on the mids, perhaps the vocal positioning is slightly being pushed forward
• Imaging and separation is very good as you can clearly pinpoint the instruments easily

Sony MV1

• This particular pairing is the most interesting to my ears
• The MV1 itself is leaning towards neutral and slight warm, with a slight lift on the mid bass
• Listening to MV1 with the M23, bass has better control and tighter, while retaining the punch, i also noticed a slightly better sub bass extension
• Slightly better separation and imaging, in terms of detail retrieval, not much changes
• Soundstage has very good width and depth to it and seems to image much better as well
• The MV1 doesn’t need super high gain as the headphone itself is fairly sensitive and easy to drive

Fiio FT3 (32 Ohm Ver)

• The FT3 by nature is slightly warm with fairly good technicalities
• M23 on high gain mode does have plenty of juice to drive FT3 to its best, however, on desktop mode with super high gain mode, FT3 exhibits better bass performance, in the sense of control, tightness and texture, soundstage is slightly wider and also pinpoint accuracy in terms of imaging
• Mids has slightly better texture and also better treble extension

Comparison (Cayin N3 Ultra)

• Uses different DAC chip (AKM4493Sx2) and has lesser power output compared to M23, but it does have several timbre coloration that you can choose from (tube, solid state)
• The sound signature is leaning towards warm and musical whereas M23 in my opinion is balancing between good technicalities and musical
• Feature wise, the N3 Ultra is rather minimal and straightforward as they have decided to forgo android OS, they are still running on android OS but a customised one, which only allows offline music playback and no app installation is supported, M23 on the other hand is more versatile when it comes to the OS, you are able to install supported apps via the google’s playstore
• In terms of power output, M23 does offers higher power output compared to N3 Ultra
• N3 Ultra is a pure DAP as its sole purpose its to play music, without any other functionality

Final Thoughts
Having tested and used the M23 on a daily basis for a month plus prior to publishing this review, the M23 definitely has what it takes to make a statement in the fast moving market with various competition. The M23 is a very versatile DAP packing loads of features within the player itself. The M23’s sound will please most listeners out there who are looking for a sound signature that is natural with a slighty coloured sound.
The power output is definitely sufficient for most IEMs and headphones out there which are not power hungry. All in all, the M23 is a very capable DAP with loads of features as well as good power output, at the time of writing this review, the OS is Android 10, Fiio has mentioned that an update for the Android OS will happen sometime soon, so for those who are looking to purchase the M23, this is definitely a good news. The M23 gets a recommendation from me for sure!

*A big thanks to Fiio for sending this over for the purpose of this review. I thank them for their support.

Introduction​

I was never a big “brick” DAP person. In the past, I have owned some cheap small MP3 players from Creative and Sandisk, but in the end I invested more in desktop setup. It all changed when I bought a FiiO M11S about 1.5 years ago. Having an Android-based player with great battery life and decent sound quality while remaining relatively small, it offloaded most of music listening time from my phone to the DAP. The M11S also served as my digital transport for my dongle DAC collections.

After that, I bought the FiiO Q15 as I was interested in the AK4499EX+AK4191EQ combination and was completely impressed by it. I was using my M11S+Q15 stack as my portable setup for a time. They made me wish for the Q15 in a DAP form, so one could imagine what kind of excitement when M23 was announced. After trying it at Canjam Singapore 2024, it convinced me to get it immediately.

FiiO M23 is the latest mid range DAP from FiiO. Due to the recent naming convention change of FiiO’s product lineup, M23 is actually placed in between M11S and M15S. In fact, it is the direct successor to the M11 Plus, taking its place in FiiO’s DAP price pyramid. M23 came in two variants: aluminium alloy ($699) and stainless steel ($899). I bought the aluminium alloy version and the leather case (SK-M23) separately; the stainless steel version comes with the leather case included.

So, does M23 improve on my previous M11S+Q15 setup? It’s a bit complicated, so let’s get into it!

Specs and Features​

Quick rundown of the basic specifications of the M23.

DAC: AKM AK4499EX+AK4191EQ
Amp: THX AAA 78+
Max Output Power: 2x 1000mW @32ohm in Desktop Mode
CPU: Qualcomm Snapdragon 660
OS: Android 10

The M23 is powered by THX AAA 78+ amplification which is the evolution of the THX AAA 78 that is in the M11 Plus. With the Desktop Mode, it is capable of reaching 1W per channel with very low THD levels and very black background.

The OS is Android 10-based, which means it came with Google Play store, allowing us to install music streaming apps easily. It also came with system-wide Android SRC bypass, making all audio outputs run bitperfect natively. I think FiiO’s Android implementation is my favourite so far.

Desktop Mode​

One of the unique selling points of M23 is definitely the Desktop Mode. FiiO has been developing this feature for a while, with the M17/Q7 having the dual power supply system with barrel plug charger, then M15S having the first dedicated desktop mode when being powered by compatible PD power supply. Then KA17 and Q15 came in with the dual USB C inputs, making it possible and convenient to access the Desktop Mode (with the new “D” icons too, starting from KA13). This culminated in M23, the first DAP with the “refined” Desktop Mode implementation.

In battery mode, there are 3 gain levels: Low, Mid, High. When you connect an 18W PD charger on the orange USB port and you switch the D.Mode switch, the battery will be bypassed and you’ll gain access to the Super High gain level; the battery will neither be discharged nor charged while in this mode.

Sound​

Gears used for testing (among other stuffs):

• 64 Audio U18S
• Thieaudio Monarch Mk2
• Sennheiser IE600, HD660S2, HD800S
• Hifiman Edition XS
• Final Audio D8000 Pro LE

I typically listen to a lot of J-Pop, jazz, orchestral soundtracks, and some rock and EDM.

I would describe M23’s sound as neutral-bright, still somewhat adhering to FiiO’s house sound. It does have a very tactile subbass response, but it is not overly boosted, just enough for the subbass to balance out the treble energy. Midrange is generally pleasant, clean, and detailed.

Tonally, nothing is really emphasised. Generally, the sound is very balanced with very little coloration. The tuning seems to be intentional to reveal the excellent technicalities of the AK4499EX+AK4191EQ to the fullest extent. Separation and layering are exceptional and crisp even in complex tracks. Soundstage is also relatively wide, but not the widest I’ve ever heard. Resolution and dynamics are definitely top notch, beyond M23’s price point.

The THX sound is also often described as being too sterile and dry. I would say that FiiO’s current implementation has addressed this criticism to an extent, but with some tracks I can still sense slight dryness. It does take away from the velvety and warm AKM timbre quite a bit, but still pleasant in many different genres. However, if you want a thicker AKM timbre taste, I’d recommend the FiiO Q15 instead.

Bass​

The bass is very well extended, maintaining very tight grip on most transducers I paired with it, generating a very tight bass control and well-textured midbass. While I don’t think it’s bass-boosted, but the bass region does sound quite distinct, probably due to the faster transients and texturing.

Mids​

The mids are detailed and layered, the star of the show. If anything I would like to nitpick, the presentation can be a tad too clinical, but that also means that both male and female vocals are equally well-reproduced and generally more versatile for most genres.

Treble​

M23’s treble reproduction is on the safe side, free of sibilance or sharpness. It’s pretty much taking the characteristics of the transducer, taking nothing nor adding more to the actual capabilities of any IEMs and headphones you paired it with.

Power​

This is where the complicated feeling starts. To my surprise, outside of Desktop Mode, the power output of M23 is actually below my old M11S (and by extension, lower than M11 Plus too). On top of that, the battery life is also below the M11S and M11 Plus, which is understandable since the DAC chip is actually desktop-grade this time. I still find that M23 on battery is acceptable with most IEMs and easy-to-drive headphones, but started to struggle with higher power demands, like with my HD660S2 and HD800S.

While writing this review, a new firmware update 1.0.1 dropped and it changed the situation greatly. A new option is added into the Audio settings called “Hifi boost”, which will give you a warning that the battery life and the heat generation will increase with this setting. However, the peak power while in battery mode is then increased from 475mW to 760mW at 32ohm! This is well beyond its predecessor M11 Plus and my old M11S, which now made it a true upgrade to them. It is a game-changer for my headphones use case, allowing me to finally drive them on M23 without having to resort to Desktop mode.

Naturally, with Desktop Mode, M23 has enough power to drive almost everything, including the aforementioned full-sized headphones to almost their full potential. Note that if you have an 18W PD capable power bank, you can activate the Desktop mode as well.

Other Experiences​

So, in about 3 weeks of owning the M23, here are a few points about my experience using it:

• Desktop mode is actually great for making M23 as a dedicated digital transport. While at home, I can plug the M23 into a DAC while in Desktop mode charged with the power USB port, while connecting the external DAC through the main USB port. This allows for the battery from getting charged and therefore prolonging battery life.
• You can also use Desktop mode when the M23 is working on the external DAC mode.
• The Hifi boost doesn’t seem to adversely affect the battery life. Normally I use IEMs most of the time while on M23, which means I operate it at lower volume settings with Hifi boost on. I feel that the Hifi boost does not really increase the average power consumption, but allows a higher instantaneous peak in the playback, so it does improve the dynamics to my ears. I now just leave the Hifi boost on all the time.
• The leather case is pretty nice, but I’m not a big fan of the metal grill back. It doesn’t feel nice in the hands and it tends to tangle with other stuff in the bag. I ended up getting a soft pouch to cover the entire thing.
• Similar to the M11S, the 3.5mm SE out doesn’t perform as well compared to the 4.4mm balanced out. I think M23 does maintain the sound signature similar, just the dynamics are still slightly behind.
• Charging is quite slow with the charging logic. It does charge quite quickly when it is at low percentages (up to 30W), then it will ramp down as it has more charge. I can understand that this is due to the battery lifespan maintenance, so I try to charge at 30-40% to avoid getting into the super fast charging. You can also limit the maximum charge, but I keep it at 100% personally. I usually get about 8h on IEMs.
• Volume touch control is quite nice, but I’d recommend keeping it on the auto-lock.
• The leather case may be quite annoying if you’re using the swipe navigation, as it blocks the sides too closely. Same goes with the notification tray pulldown, quite hard to pull when the leather case is installed.
• Very fluid OS, I think it’s one of the smoothest Android implementation even when the M23 is still on the aged Snapdragon 660.
• Size-wise, since it is very close to my M11S size, I didn't really have much problem with it. One of the reasons why I skipped on M15S was the size, so I’m glad that the M23 fits just fine.

Overall I’m still very positive with the M23, especially after the firmware update.

Conclusion​

With the rise of dongle DACs, it does pose a question to everyone’s minds whether owning a DAP is worth it, and it is often cited that DAPs under $1000 are not worth it. Well, as dongles get more expensive and DAPs are getting cheaper and better, I think the age of DAPs is still far from ending. M23 is a proof of that, giving enough features, sound quality, and package that would justify its existence in the age of smartphone+dongle. I would highly recommend the M23.

//Update: The price in Germany dropped to 699 which is the same as the M11 Plus ESS, hence i do recommend it over the M11 Plus ESS, obviously and upgraded to 5 Stars. If you do not own an M11 Plus ESS already, the M23 is the better device.

I owned the M11 Plus LTD, the M11 Plus ESS and, of course, i had to test the new M23.

And the first thing that surprised me is that its basically not different from the M11 Series, which is a good thing. I liked them exactly how they where. I have high praise for this DAP and it is a good product overall.

And the M23 is better in some aspects, as it has more power. But i don't need that feature, even with large over ear headphones, i was still totally fine using Low-Gain and very very rarely used Mid-Gain (Never had to use High-Gain). So that is already one feature that, i personally, have no use for.

In my initial review is mistakenly mixed up the M11 Plus and the M23 noise floor. The M23 is actually lower which is a positive. I couldn't hear the noise floor on the M11 Plus with any earphone i tested, but if you have an insanely sensitive one, that might make a difference for you.

The Sound Quality is, as far as i can tell, unchanged. Maybe there are minor changes i need long listening sessions for to catch them, but at least in the 4 hours i listened to music, it was pretty much identical to the M11 Plus ESS.

And that is, for me, the biggest bummer. The Sound is unchanged, the SoC is unchanged, the Android is unchanged. You basically pay 750€ (In Japan its roughly 1.5x the price, a joke) for the exact same device, but with slightly higher power (probably nobody needs, you could drive the Susvara, easily, with the M11 Plus).

I do not see why someone would want an M23 over an M11 Plus ESS, especially when the M11 Plus ESS is going now for cheap everywhere.

The M23 is just no upgrade. It uses a different DAC on paper (that comes with disadvantages) and has more power (which comes with disadvantages). Thats it. Same but different.

So i highly recommend to check the price difference between the M23 and the M11 Plus ESS and grab the M11 Plus if you can. There is not really a difference.

A lot of people don't like cross-company comparisons, so i did not put this into my rating, but just for the sake of it.

To put this into context. Both the ZX500 and ZX700 (Inferior in terms of features/power, superior in terms of sonic performance) are cheaper than the M23. And the ZX500 is now several years old, you can grab an ZX500 in "like new" condition for 250€ and have the superior sound. You can get a like new WM1AM2 for the price of the M23. Yes, apples and peaches because used vs. new and so on.

But Money is Money. Unless you're not rich/have an unlimited amount of money, i can not recommend the M23 to anyone right now.

If you don't care about the price, get it. Its a good DAP. Not good enough to justify the price tag, but its good. If the price doesn't matter for you, you will be as happy with it as you was with your M11 Plus ESS.

FiiO M23 - A feature rich DAP with desktop level capabilities​

FiiO new M23 DAP is a both natural progression on from the M11 Plus but with the addition of some clever new features the M23 is now blurring the distinction between a portal DAP and a desktop headphone Amplifier



But is a DAP the right device for you? Let’s find out in this review.

Note: I would like to thank FiiO for providing the M23 for the purposes of this review - if you are interested in more information about the M23 check it the details: here

Why use a DAP?​

I have a section later where I explain my own personal history with DAP’s and from that long history, I have derived a bunch of what I feel are key benefits of a DAP, so before getting into this review. Here are my thoughts on why a DAP might be still a relevant device for you.

In my opinion, a DAP has always had 4 ‘core’ requirements:

1. Browse and play my own music, ideally from on-device storage, so I can use it ‘offline’
2. Be portable enough to carry with me ( to places where I cannot get mobile data streaming like an airplane )
3. Play the music in the highest possible quality - even when Smartphones had headphone jacks this was a problem - the Apple Dongle can only go so far
4. Good battery life and the ability to save the battery life of your primary ‘smartphone’ by being a separate device - numerous times over the past 20 years with DAP’s, I have ‘saved’ the battery on my primary smartphone by using an alternative ‘companion’ device for music when on long ‘business’ trips or on holidays

There is also one more requirement that have become more relevant for me in recent years and that is to have a device that doubles as a desktop DAP with enough power for ‘good headphones’. This is because I often work in shared space so having a portable ‘desktop’ amplifier that I can bring to different location but also works with some of my more demanding closed backs gives me a great working experience.

You might still think your Smartphone is enough (and it might be for your specific use-case) but there is also a cost factor involved. This can be either related to the cost of buying the initial storage on your smartphone or the cost of roaming mobile data streaming:

1. Roaming mobile data charges (especially outside Europe) can mean I get charged something like Eur50 for one hour of music streaming from Spotify or Apple Music
2. Buying say 1TB of extra storage upfront with my smartphone can add $200 to the cost of the smartphone

So lets get into the detail on the M23 ..

Retail Box, Unboxing Experience and Hardware​

The FiiO M23 comes with a nice packaging reminiscent of a mobile phone:

The back of the box:



Upon unboxing - in a sleek package that mirrors its premium design:

Contents:​

Inside that box:



you find the M23 DAP itself which comes pre-installed with its protective cover:



Under the M32 you get a microSD removal pin and some sections with manuals and the usb-charger:



Finally, this is everything that is in the box, a USB cable for charging and data transfer, and a user manual that provides essential startup information:

First Impressions and a device tour:​

The M23 has what I would call a ‘chunky but compact’ size, and it is heavier than I would have thought looking at it, with non-stainless steel version coming in over 300g and the stainless steel version which comes in at 390g. My much larger iPhone 15 Pro Max is merely 220g by contrast, but as we will see later in the specification section there is good reasons for this weight and its size means it still fits easily into my pocket and I had zero problems popping into my laptop bag when going to the office.

I like how FiiO not only provided a case for the M23 but shipped with the case on, its weight probably does mean its screen might not survive a fall onto concrete without this protective case.

Let do a little tour around the different connections of the M23:

Headphone jacks​

FiiO dropped the 2.5mm headphone jack which the M11 ‘series’ had, so we get a 4.4mm and 3.5mm headphones jacks:

As you will see later in the specifications, the 4.4mm balanced output can get to a very respectable 1000mw + 1000mw per channel in the ultra-high gain mode and one of the reasons I feel this ‘mobile’ DAP can double as a desktop unit.

The audio hardware behind these headphone jacks is very impressive with FiiO utilising a new THX AAA 78+ headphone amplifier but more on this in the Audio Hardware section later.

Hardware Buttons​

So the hardware buttons on the righthand side of the unit are very useful, with Next, Previous and Play/Pause buttons.



There is also a ‘Hold’ switch and finally the ‘D mode’ switch for the Desktop mode.

The Lock button has some software configuration you will see later on where you can decide to allow some buttons to still be active even with the device is locked.

As for the ‘D Mode’ switch, I will get into this in more detail later but this is a welcome feature and part of the secret of this device being a capable desktop headphone amplifier.

USB and MicroSD connections​

On the bottom of M23, there is the microSD slot which supports up to 2TB of storage. If you read ‘my mini history with DAPs’ later on you will realise that I immediately went out and bought a 512GB microSD and filled it up with a good selection of my ‘offline music’ collection as I love the ability to carry all or most of my music collection offline.



The dual usb-c is another great innovation which I have seen in a few recent FiiO devices. So one is for power only while the other can be both power and data. While this might seem strange there is a clever reason for this, you do not want you mobile phone or even laptop being drained, providing power to the DAP when using this DAP as a usb dongle. So if you have a desktop usb-c cable connected to the power only usb-c you can happily plug your mobile into the other usb-c and the M23 acts like a high quality DAC for the mobile without pulling any power from your mobile.

The other thing of interest with these usb-c connections is when desktop mode is enabled there is another clever feature, the usb-c power connection will provide power but will skip the battery, therefore if you have it in ‘desktop mode’ mostly your battery will not suffer from typical ‘pointless’ charging cycles that cause battery issues long, this should greatly enhance how long the battery lasts in the long term.

Volume slider, Power and Multi-function button​

Finally on the righthand side we the power button, the volume control ‘slider’ and a multi-function button:

You are provided some software configuration around both how the volume control works and the colour of the light (and when it flashes ) around the Power Button. I will shows these options later. The volume slider has a nice tactile feel and will be familar for those with a previous M11 series DAP.

Note: While the multiple function button is both a great option, I do feel FiiO could do a little more with this button. Currently it has the following functions availalbe to be assocated with it:



But, I feel this could be an excellent button to do automation tasks or even to allow the ability to select an application launch with this button or to toggle ‘Roon’ (more on the ‘Roon’ support later on ). For example, I often use PlexAmp on both my Smartphone and portable devices (as an alternative to Roon) and it would be nice to just launch Plexamp with a single hardware button.

Screen, CPU and the internals​

Both the screen and the CPU on the M23 are good for a DAP but are poor compared to your typical smartphone. In fact, I found it interesting that FiiO are using the same CPU the Snapdragon 660 that I was using in my alternative ‘Android’ phone that doubled as my DAP a few years ago, the Xiaomi Redmi Note 7. So I think FiiO might have upgraded the hardware in this release, but I should also say at no point did the software feel ‘sluggish’.

The LCD screen is good quality for the screen size at 1440*720, it is the least you should expect in a 5.5 inch screen - if it was a larger screen I would expect high resolution and again I would have thought FiiO might have switched to an OLED display.

Looking at the overal specifications, it is obvious that FiiO focused more on the Audio hardware which I believe for a DAP is obviously the correct focus but those expecting 2024 smartphone specifications for CPU, memory and screen will be disappointed.

But before we get into the details of Android, let have a look at the audio hardware next.

Audio Hardware​

FiiO provides this nice architecture diagram detailing the full audio path:

DAC:​

Utilizing AKM’s flagship AK4191EQ+AK4499EX DACs, the M23 offers an improved signal-to-noise ratio and much better measurements than its predessors as you will see in the measurement section below. This technology ensures a cleaner sound and higher audio resolution and a very neutral sounding DAP.

Amplification:​

Features a 4-Channel Fully Balanced THX AAA 78+ Headphone Amplifier providing a high power output of 1000mW at 32 Ohms in Super High Gain mode. This setup ensures that the M23 can drive demanding headphones at high volumes without distortion. While not at the flagship power levels of the M17 it does move the bar as to what you should expect from a DAP at this price point.

Sound Profile:​

The M23 delivers a very coherent, neutral tuning with an energetic presentation and excellent bass punch. It remains dead silent across various IEMs but powerful enough with enough headroom for all my planers to get that bass punch, making it versatile for most environments.

Given that the FiiO Equaliser is a key built-in feature, I feel having a neutral tuning is ideal allowing EQ customisation for those you like do like to customise the sound signature.

Android, User Interface and Software Provided​

The M23 was shipped with Android 10, but I believe an upgrade to Android 12 will come in May. I believe this won’t change too much of the User Interface though there is a new ‘material design’ in Android 12 so some of the screenhosts provided in this revew will look different once the Android 12 update is available.

Other key things in Android 12 will be updated Android Security, better notifications and some changes around the media player (though it remains to be seen how FiiO customise the media player experience with the M23 in Android 12).

The M23 includes an online upgrade application which will be useful when this update is available:



In fact during my review - an updated popped up:

Display and OS​

Here is the current ‘About’ screen with some of the software / hardware specifications:

M23 ‘Modes of operation’​

One of the most important configuration options FiiO provides is the ability to run the M23 in different Modes:

Mostly, you will probably run the M23 in ‘Android’ mode and that is what the majority of this Review will show, but the other modes are very nice to have and I did utilise them a few times in the past few weeks.

So, Pure Music mode is a nice option if you just use the FiiO Music application as it effectively launches just that application so there is no distractions or application switching, but you still get access to things like the PEQ filters and the Audio configuration.

With USB DAC mode effectively turn the M23 into a headphone ‘Dongle’ DAC for your laptop or smartphone. The M23 turns into a simple device showing the status of the connection:


And when connected it looks like this - you get the access to up to 384Khz in Usb DAC mode:


With Bluetooth Receiver and Airplay Receiver modes are nice extra are great for situations where you have the M23 setup with ’lineout’ connection into an speaker Amplifier or powered Amplifier and you can ‘cast’ to the M23.

These 3 have a similar UI to the usb-dac mode above when activated, basically the M23 is just waiting to be send a stream via bluetooth or Airplay.

There is another mode of operation, when ‘Roon’ is enabled the M23 Acts as a full “Roon Ready” device. I have a separate section below about ‘Roon’.

Android Audio customisations and settings​

Lets get into some of the customisation FiiO have made for Android with the M23 - since its ‘stock’ Android, I picked some of the main customisation here, so you can see what can be configured especially related to the hardware of M23:

Global Settings​

As you can see launch into further areas of customisation from this screen.

Let’s check out a few examples:

Light Colour customisations​

There is a light surrounding the ‘power’ button and this is how you can configure that light:

Lock screen buttons​

You can configure what hardware buttons are active when the device is locked - very handy when carrying the M23 in your pocket:

Audio Settings:​

Lots of useful options to adjust how the Audio is handled on the M23:



As you can see above, FiiO have moved the Bluetooth settings from the ‘Android Developer’ into a separate menu here, so you do not need to turn on developer settings when you want to configure the default Bluetooth Codecs and its associated settings.

Super Gain Mode:​

I like how when the M23 detects you have the right level of power from your usb-c connection it pops up the following screen (as if you are playing a game and have ‘unlock’ a secret level):



With this mode enabled you have an extra Gain level available:



And as you will see in the measurement section below - this means you can get that desktop level of power from the Balanced output.

FiiO Music Application​

The most important application (especially if you want to use your own music on a microSD card ) is the FiiO Music application. Both the Android Mode and especially if you switch to ‘Pure Music’ mode you will be using FiiO built in Music player.

Though of course you can install whatever your favourite Android Music Application (e.g. Neutron Music Player) or all the main streaming platforms music applications also like Spotify, Apple Music, Tidal, Qobuz etc

I found the FiiO Music application much better than I initially thought, though it does lack a little bit of customisation compared to some other music playing applications. But I was mostly very happy to use it with my offline music collection.

But let’s get into a little bit of detail about the FiiO music application:

It is relatively good at customisation with nice layouts for the different screens:

Note: If you switch to landscape mode in the player:



You get 2 very small VU meters rather than the one.


Once switched to Landscape all other screens will display in landscape mode nicely:

Note: that white area at the top of the screeenshots here are only a sideeffect of taking a screenshot and were not visible when the device was in landscape mode

Music Profile / Settings​

You can see this is where you can ‘scan for music’ so after ou have put your music on a microSD card - with my 512GB card it actually took close to 40 minutes to finish scanning but once it has indexed the music even after restarted the Application would start-up immediately and have access to all previous scannned music.

There is also a DLNA ‘browser’ within this section of the Application and this worked well looking for the many music servers on my network:



There are lots of settings in this section of the application:



Including a section on DLNA transmitting and receiving:



The crazy thing is I am only touching on some of the other capabilities available, there is a ‘Lab’ with some extra new features, there is Car Mode where you get a simplified player when using the M23 in your Car, there track metadata editing features, playlist management etc

FiiO Link Application​

Another nice application that FiiO has provided is the FiiO link application - basically with this enabled on the M23 you can control your music (and settings) from another device i.e. your smartphone (including iPhones) to remotely control the M23. This is extremely handy if you want to leave the M23 connected to an amplifier or powered speakers and control the music playback from your smartphone.



Basically you start the FiiO Link from the above screen, it will be waiting for a connection:



Once you start a FiiO Link client Application on your smartphone you see the M23 and can control the device.

For example via IOS:

FiiO Link ‘client’ on iOS​

Here is how the FiiO link client looks like on iOS:





Some Audio settings are easily changeable remotely:



But the key thing is you get remote control over the M23:



Overall this was a great feature and again as is the theme of this review means the M23 is much more than just a simple DAP it can be used in many flexible ways.

FiiO Equaliser​

I like how FiiO are standardising their Equaliser Application across devices and platforms, so it’s a very familiar experience here to the one you get configuring the EQ for the KA17 with the EQ defaults and 3 ‘spare’ custom profiles to edit yourself and the Advanced button to open up the PEQ capabilities.

There are features I would love added to this equaliser and FiiO have confirmed they are working on some of these features like the ability to export and import PEQ filters (for example, allowing Squig generated EQ filters to be imported here) and much more custom profiles ‘slots’ available as I have lots of EQ settings I would like to store.

I would also love “autoEQ” integrated though that might be harder. One thing I did notice in my testing with bluetooth headphones was the EQ was not applied to the bluetooth audio - though this might change with the Android 12 update.

Here is an example of what editing the PEQ capabilities look like:

FiiO Market AppStore​

As well as supporting Google Play Store the M23 comes with FiiO own ‘AppStore’ the FiiO Market. I imagine in China where I believe there are limitations on the Play Store, this is a key way to download audio applications:

But it is probably less relevant for those who want to stick to Google PlayStore.

Roon Support​

For those who haven’t experienced Roon it is an incredible beautiful Audiophile application that seamlessly integrates your own music collection or your Tidal / Qobuz subscriptions with a massively detailed metadata database providing albums and artist reviews as well as very detailed track information included who played on what track.

Together with all this information roon provides detailed technical information about how your Audio is being played by your hardware and even the ability to add filters for PEQ and other capabilities directly within the one Application.

I believe FiiO got certification for the previous generation of DAP, the M11 Plus and the M23 is currently using that certification to be ‘Roon Ready’:



A Roon Ready device has lots of extra capabilties within Roon e.g. the Audio Path:

Because the M23 is a Roon Ready endpoint you can remotely Cast music from the Roon Application. So when you are using the M23 as a Roon Ready device you do you get a nice album art of what is playing and some sensible controls - but mostly you are controlling the device from Roon itself:



I won’t get into all the details but for me being Roon Ready is another amazingly useful feature of the M23 that sets it apart from other DAPs and even other desktop headphones amplifiers.

Specifications and Measurements​

Output Power:

As you can see there are lots of different output power options depending on whether you are using the balance or single ended outputs and whether desktop mode and super gain is activated and the impedance of your headphones:

So the star of the show here is the Balanced output in Super Gain Mode a 1000mw is excellent for a ‘portal’ device and more typical of a good desktop amplifier. For comparison the M11 Plus provide a max of 660mW + 660mW into 32Ω. But a ‘real’ desktop player like the FiiO R7 provides full desktop power of 3650mW + 3650mW into 32Ω.

I believe this power and the desktop mode that enables this “Super High Gain” mode really allow the M23 to fill a gap for people who want good desktop power but also need a device that is highly portable.

Audio Quality:​

The tonality is neutral with a slight tilt towards a brighter, more energetic signature, which pairs well with warmer sounding IEMs or amplifiers.

Audio Precision Measurements​

Note: These are provided by FiiO, but I thought I would include these 2 in this review for completeness and to give you an idea of how clean the performance of the 3.5mm and balanced outputs are in super high gain mode:

PO Super High Gain Mode 2V@32Ω

BAL PO Super High Gain Mode 4V@32Ω


These measurement show desktop amplifier level of performance - the Balanced output has slightly worse SINAD but this is effectively because of the extra power you are getting.

My personal history with DAP’s​

Feel free to skip this section - this is my personal history with DAP’s but I felt it might give some context to why I still think DAP’s are good even in a world where your Smartphone can ‘do everything’.

So, my first experience with what might be called a DAP was with a Compaq iPaq PocketPC around 2001 - I was working in a company developing stockbroker ‘dealing room’ applications, and we had the idea of a high powered (but expensive) mobile experience might appeal to rich customers, so I got to use and develop for a PocketPC ( Windows CE ) this was also about the time that Napster was starting off and myself and some of my work colleagues were encoding our CD collections with Fraunhofer MP3 encoder. I distinctively remember having about enough space for a single Belle and Sebastian album to be loaded onto my development iPaq and listening to it on a plane with headphones on a trip to London. It was a revelation (this was a few years before the iPod was launched). I immediately went looking for devices with more storage.

Fast-forward a few years, and I had an Archos DAP with a ‘huge’ 10GB HDD and brought this with me on a week-long trip around Germany, the ability to call up any of my 100 CD Collection on its tiny screen was just amazing. I quickly upgraded Creative Zen and ended up with huge by those days collection of 500 CD’s for many other work trips. One key problem with these devices was how slow it was to load the devices with music and once it was loaded how clunky the UI was, but I resisted the temptation of the iPod for a few years.

I remember owning a few other DAP around this time from brands like Meizu which in fairness did start to push better DAC and headphone output with some iPod like touch wheel experience. But eventually I got a job working with a Telco and luckily for me, my job allowed me to experience with the latest phones. I was probably one of the first people in Ireland to have an iPhone and a Nexus device but from a DAP like experience I remember having the opportunity to have both an iPhone 4 and a Samsung Galaxy S1 (where I bought a ‘huge’ 32GB card for storing my music collection).

I flip / flopped between IOS and Android for a few years, typically having a Pixel just for the camera but the reliability and build quality of iPhone meant they were (and still are) my primary phone but had been once Apple removed the headphone jack, I would always have a separate mobile / music device (even a few iPods alone the way), I mostly settled on a few different Xiaomi Redmi mobiles which still had external storage and the headphone jack and were fast enough for browsing my ‘offline’ collection.

The only change I have had in the past few years is in the quality of both the headphones, I now typically bring with me has meant I need a better device for my ‘offline’ music collection and this has lead me to try a few mobile ‘solutions’ over the past few years. While the Apple usb-c dongle is good enough for some headphones, I wanted the ability to have both PEQ and more output power for my headphones and IEM, I initially switched to a Qudelik 5K but a few months ago started using a FiiO KA17 and while both have their pros and cons the fact you still need a ‘device’ with your music and these devices will draw power from your smartphone has brought me back to feeling that a DAP is still the perfect solution.

So, please excuse my personal history with DAPs, but I hope it provided some context for the rest of the review, I will try and make the rest of this review a more visual experience with less text.

Rating:​

I have given the M23 a 4.5 star pragmatic rating, it has a fantastic feature set, obviously built over the years by FiiO on their previous Android DAPs but now with the added Desktop Mode, the extra Super High Gain mode and the upgraded THX amplifier making it a superb offering.

I dropped it 1/2 point as the Android ‘hardware’ i.e. the CPU, Memory and screen resolution are a little out of date ( though the audio hardware is excellent ) and given it currently has Android 10 it currently seems a little date. When the Android 12 upgrade is available i will update this review and I may update the rating at that stage.

Conclusion:​

The FiiO M23 blurs the difference between a portal DAP and a desktop headphone ampiflier and stands out in the mid-to-high-end DAP market through its robust feature set, superior build quality, and exceptional audio performance. It represents a significant sonic upgrade over its predecessors and offers a compelling choice for audiophiles seeking a portable, feature-rich audio device.

The M23’s precise sound signature, coupled with its practical design and connectivity options, makes it a highly recommended purchase for those looking to invest in a high-quality, reliable DAP.

FIIO M23
AK4499 EX + AK4191EQ & THX AAA 78+
$700


Before I start this review, let me thank FIIO for providing the unit in for review, rest assured my review is 100% my own personal opinion.

You can check the M23 here
https://www.fiio.com/m23


Unboxing
What you get inside the box :

• DAP
• Micro SD Ejector
• Included Silicone Case
• USB C to C Cable
• Type C to A Adapter
• Manual & Documents

Build Quality

The M23 screen size is 5.5inch with1440 x 720p resolution, it looks good for a DAP, but not smartphone like good, if you know what I mean.

The M23 comes with a tempered glass screen protector and silicone case pre-applied from the factory.

I believe there are 2 variants of material type for the M23, stainless steel and aluminium one, the one I have right now is the aluminium one.
For the stainless steel version, you get a leather case instead of silicone case.

Left side of the M23 has a touch sensitive volume that can be enabled-disabled and also traditional clicking volume control.

Personally myself disable the touch sensitive one because I don't want to accidentally blast my ears with loud music if I accidentally swipe up the touch sensitive button.

There is also a power button with LED and multifunction button that u can map its function on the left side of the DAP.


On the right side, there is a rewind, play, forward button, Desktop Mode switch and hold / button lock switch.

On the above, there is 4.4mm and 3.5mm port

On the below there is a micro sd slot, USB in and power in port.

For charging, I suggest to use the power in port, because it is more faster compared to the USB in one.

Back side of the M23



Specs

Power & Desktop Mode

with high gain the M23 can give you 475mw @32ohm and 55mw @300ohm, this is actually already quite high power to be honest, but if you really want to push lets say low sensitivity high impedance headphone, you can use the super high gain accessible using the desktop mode, it can provide up to 1000mw @32ohmand 240mw @300ohm, both figures is for the 4.4mm port.

Also desktop mode make it safe to plug your M23 as a desktop unit.
It basically bypass the battery charging system, and completely power the M23 using the power in port, so your battery will be safe.

Battery Life

I get around 9.5 hours of battery life from the 4.4mm port using a planar IEM.
The M23 also supports 30w power delivery charging, it charges quite fast actually to the 80%, around 1 hour.
But 80% above take quite long time.


Input / Mode selection

There is an option for Android Mode, Pure Music Mode, Air Play, USB DAC Mode, Bluetooth Receiving Mode, and Roon Ready.
To be honest with you I rarely touch any mode besides the Android Mode.
Oh also one thing I would like to mention, the M23 can get a bit warm to the touch after several hours of use.

Sound
Neutral – Warm

Bass : Full, Deep, and Well Extended
I felt like the bass has some kind of highlight on its presentation.
It has that dense feeling into it, like there is this weighty feeling to the bass sounds so it renders object very well.

Midrange : Lush, Weighty, Relaxed
The presentation of M23 midrange is just like the typical signature sound of AK4499EX + AK4191EQ implemented on all FIIO's product
Just like Q15, K9 AKM, I praised it because how natural and lush the midrange presentation, and same with the M23, I love it.
It renders midrange in an elegant way, good note weight, lush, and relaxed yet natural, musical and yet very resolving at the same time.

Though if you wanted a more aggressive presentation, the M23 / Q15 / K9 AKM might not be the device for you.

Treble : Smooth, Extended, Very Detailed
The treble presentation of FIIO M23 is smooth, complementing the lush presentation of its midrange, but its extended at the same time, and on top of that, its very resolving and detailed.

There is this airy feeling without making your ears tired, and its very good, It can renders micro decay very well, tested even with planar type IEM / headphones.

Usually planar type IEM / headphones at least for me always has that impression of the decay is very short, but not when plugged in to the M23, it has proper decay of sounds ,and I really love it.

Technicalities
for $700 I'd say its “Very Good”
It offers practically almost the same similar technicalities like the K9 AKM but in portable form factor.

Stage : Very Good
Grand and well rendered layering
It sounds expansive just like a desktop unit for real, I don't know how FIIO made it, but yeah it sounds just as expansive as the K9 AKM.

Imaging : Very Good
It can make my trusty cheap Moondrop Chu 2 sounds holographical, no joke.
It rendered sounds very well with many layered information that you can easily image the sounds.

Detail Retrieval : Very Good
The M23 has a very good detail retrieval on all of its frequency (bass – mids – treble)
It sounds very resolving.
The M23 is really a joy to listen to, it sounds relaxed but full of micro details.

Separation and Positioning : Very Good
Thanks to its grand and well rendered layering of the stage, separation and positioning of the M23 is also very good, you can easily pinpoint and separate whatever you want with this DAP.

So basically for the technicality part, I was mind blown when I first tried the M23, because my expectation the M23 would be like below K9 AKM in terms of technicalities but no, Its so close to each other, yes its that good.

Comparison

FIIO Q15
The Q15 is almost like the M23 without operating system and minus THX AAA 78+ amp.
Is it worth it to spend more and get the M23?
In my opinion YES.

The M23 has superior bass control compared to the Q15.
M23 also has this more weighty presentation of the bass and it help renders object to feel more realistic and natural.
As for technicalities, the M23 also take it to the next level, basically what I said in my K9 AKM review applies here.
Its just like Q15 on a steroid, every aspects of the technicalities is noticeably improved.

Conclusion

If you really like the K9 AKM sound and hoping there is a portable version of it then here is your answer and solution for it.

The FIIO M23 is a device that you really can't underestimate.
It offers decent processor, very good screen, and decent battery life, somewhat updated android OS version and the flexibility of desktop mode.
You can literally use the M23 as a desktop unit too if you wish it for.

I can easily recommend the M23 for its price. Trust me, It offers a very good value without touching the $1000 price point.

Just in case you're Indonesian or understand Bahasa Indonesia, you can watch the M23 review video here



Thanks for reaching this far !

-littlenezt.

The FiiO M23 is the latest DAP from FiiO. With an RRP of €749, it is priced between the M11s and M15s. The M23 not only continues the classic hexagonal honeycomb design and 18:9 format of the M11 series, but also offers significant improvements in configuration, performance and ease of use. The aim was to create a mid- to high-end DAP that offers both outstanding performance and an excellent listening experience.



The M23 uses AKM's flagship AK4191EQ+AK4499EX. FiiO also uses "DWA ROUTING Technology" to further improve the signal-to-noise ratio. This technology enables a cleaner sound background and higher audio resolution, resulting in a more relaxed and natural sound.

The M23 is the first DAP from FiiO with two USB Type-C ports, one of which is dedicated to power input only (POWER IN). When this dedicated USB Type-C power port is connected for fast charging, the Super High Gain mode can be activated for more gain and more output power. In this mode, the output power can be increased up to 1000mW@32Ohm. In normal battery-powered mode, the M23 reaches a maximum power of 475mW@32Ohm, which is still more than enough for all IEMs on the market. Even the FatFreq Grand Maestro can be driven at high volumes. In this mode, the other USB Type-C port consumes no power and is therefore suitable for connecting the M23 to a smartphone for use as a USB DAC.

In addition, the M23 naturally also has the patented desktop mode (D.MODE), which can be activated with a switch. When D.MODE is activated, the M23 is fully powered by an external power source. The built-in battery is not used. It is neither charged nor discharged. A 5500mAH battery is used in the M23. A dual-mode fast charging system combines extremely fast charging and normal fast charging. When the battery is low, extreme fast charging is used to provide a safe charging speed of up to 30W. When the battery is approaching a charge level of approx. 80%, the M23 switches to the somewhat slower fast charging method, which is more gentle on the battery, in order to increase the battery's service life. With this charging method, a completely empty M23 can be charged to a capacity of 80% in approx. 1 hour. In symmetrical mode, a fully charged M23 lasts me just over 8 hours. A very good value!

The M23 uses amplifier designs from THX. These are considered to be particularly clean and linear. The THX AAA 78 headphone amplifiers used in the M11 Plus and M11 Pro have been further improved and implemented in the M23 as THX AAA 78+. This new design enables a more powerful sound reproduction with extreme precision.

Further technical details include the use of the proven Snapdragon 660, 4GB RAM, 64GB ROM, a 5.5-inch display with a resolution of 720x1440 in 18:9 format and 4 gain levels. The M23 will initially be delivered with Android 10, but will be updated to Android 12. The M23 comes with 6 different modes such as Android mode, Pure Music mode, Airplay, USB DAC mode, Bluetooth Receiving mode and Roon Ready mode. An integrated 10-band PEQ can be used in each mode.



The scope of delivery includes a transparent silicone case, a USB cable and instructions. The DAP itself looks very high quality in a great blue design. There are no sharp edges or anything similar and it sits very comfortably in the hand. As I currently use my DX320 MAX Ti almost exclusively, I now realize how big and clunky this iBasso DAP actually is. The M23, on the other hand, is tiny in size and weight and fits easily into any trouser pocket. And it's also great that it has a lock button. How much I wish my MAX Ti had this, because you often reach the buttons unintentionally while wearing it. With the volume control, you have the option of doing this via two buttons, as you would with other DAPs, or via a rectangular touch area on which you can slide a finger up or down to adjust the volume and, depending on how quickly you move your finger, it can be adjusted more quickly than with individual presses. I think the concept is very good!

For the sound test, I initially let the M23 play for 30 hours until it had developed its full potential. In this review, I have selected some of my own consorts for operation and these include: The Austrian Audio Composer, Fir Audio XE6 and 64 Audio Fourte Blanc. I also paired it with the iBasso PB5 Korgtube amp and looked at how the tonality changes. In the past, I have already tested the FiiO top model, the M17, and the M23 is very similar in terms of tonality. It is a rather neutral DAP without any coloration with brighter timbres compared to the DX320 MAX Ti or even a Shanling M8, which has a much warmer sound. The FiiO M17 is a very technical DAP and gets the maximum out of its ESS DACs when it comes to sound precision and separation. The M23 is not quite at this level. However, it also only uses one AKM DAC and is much smaller and much handier. Unfortunately, I don't know the M11s and M15s models and can't make a comparison with them. However, I think that FiiO has classified them correctly in terms of sound and that would be M11s<M23<M15s<M17. It's quite remarkable what you can get these days in terms of sound for the price of €749! An M17 is twice as expensive but never twice as good. The latter still has significantly better reserves for driving a Susvara or Abyss 1266 TC. The M23 can't do that even in desktop mode with the highest gain level. For IEMs, a Composer or a Utopia, however, you don't even need the desktop mode, as these models are easily satisfied with the performance in battery mode. If you are looking for a small and very good-sounding DAP for on the go, the M23 is a better choice than the much larger M17.

Tonally, we are dealing with a neutral DAP with very good technical qualities in terms of detail and separation. Only the significantly more expensive DAPs offer a direct comparison and show that it can be even better. I listened exclusively to the M23 for a few days and didn't really miss anything during this time with my headphones and IEMs. The M23 is an energetic DAP and doesn't have such a romantic character as the Shanling M8, for example, making it a very good combination for the somewhat warmer IEMs such as the XE-6 and Fourte Blanc. Due to the brighter, more energetic presentation, it can also be paired with a warmer amp such as the iBasso PB5, resulting in a slightly brighter timbre overall than when paired with the DX320 MAX Ti. I would no longer recommend the latter combination with an XE-6, for example, as it then becomes a touch too warm. With the XE-6, on the other hand, the M23+PB5 combination works very well! What bothered me a little is that the lineout on the M23 is fixed and doesn't have any gain stages. This means that the PB5 has a little too much power and the volume range is very limited. Of course, you can also go from the headphone out into the PB5 and then have the gain stages available. But this leads to so-called double amping, i.e. the output passes through the amplifier stage as well as the DAC stage and can lead to a loss of sound quality. I also tried this variant and preferred it in the end, as I could not accept the disadvantage of the excessive volume range of the pure lineout. I was happy to accept the very slight loss of sound quality.



From the bass to the treble, there is nothing that stands out in the performance. Everything sounds very balanced. The M23 sounds incredibly clean, which is probably due to its THX amplifiers. A DX320 MAX Ti pulls the sound even further apart with a larger stage. In terms of bass punch, they are almost on a par. The M17 hits a little harder. The mids are designed for maximum separation and detail and are not as full-bodied and natural as the MAX Ti. Here, the M23 has more of a FiiO house sound, just like the M17, i.e. without any warm melting in the mids, absolutely free of coloration. The treble is detailed and free of sibilants. The transition from the mids to the highs is smooth, so that even micro-details are not masked.

The Austrian Audio Composer is known for its energetic playing style. Does it also suit the M23? At first I thought it might be too much of a good thing, but this combination works really well! It's the treble response of the M23 that makes it sound pleasantly smooth but with real drive and punch at the bottom! A pleasure for fast music such as prog or speed metal!

The Fourte Blanc with its more restrained presentation is also brought to life, so to speak, with the M23 and plays a bit more energetically than with the DX320 MAX Ti. Incidentally, the M23 is absolutely dead silent with all my IEMs. And the volume range in low gain is absolutely fabulous! With the Fourte Blanc, my normal volume is between 30-40 in low gain. So you can still make very fine adjustments where I only have a handful of positions available with the potentiometer on the DX320 MAX Ti and often have to make fine adjustments with the digital volume control.

The M23 is the best DAP I've ever heard in the price range up to €749 and I can give it a clear recommendation to buy. Anyone looking for a technically very good, rather bright, neutral DAP without any tonal embellishments and the whole thing in a portable package can buy it without hesitation