FiiO M15 Review

With 13 years of experience behind them, FiiO have represented an unstoppable force in the personal audio scene. They have always constituted the epitome of what an audio brand should be; humble, fairly priced and willing to listen and improve upon consumer feedback. With that said, the Chinese audio brand set themselves a challenge – to create the best portable music player using all their experience within the growing industry.

The result has culminated in the FiiO M15 flagship portable player retailing for $1299. At this price point, FiiO have ventured into new grounds since their latest $649 Fiio M11 Pro DAP. This now places it in competition with Lotoo’s PAW 6000 DAP and Astell & Kern’s Kann Cube.

The M15, whose design is inspired by western classical architecture, improves upon its predecessor with higher grade resistor and capacitor components. With the implementation of AKM’s twin AK449EQ’s DAC chipset, an NDK femtosecond crystal and Samsung’s Exynos 7822 processor it is clear to see FiiO’s efforts of redefining the Hi-Fi listening experience.

Fiio M15

The Packaging

FiiO have stepped up the unboxing experience since previous reviews with a packaging fit for a flagship product. The outer sleeve has a multicolored glow which moves with light and houses a secure inner North American Black Walnut box. FiiO have ditched the prior standard packaging for a more premium look which shows off the M15 nicely. Also included is a USB C to USB-A charging cable, pin for memory card tray, user manual and coaxial converter cable. It is disappointing to see that FiiO have not included any protective case especially seeing this is their top-end product.

The Design & Build

The FiiO M15’s design is a stark departure from yesteryear generation products. Instead of the angular design philosophy, FiiO have embarked on a curvilinear aesthetic. The reason behind doing so has aptly been described by CEO James Chung.

With the M15’s internal components and improved battery capacity, space optimization becomes key and the ‘Bauhaus’ rational design concept’ applies where styling serves function. Hence, the M15 improves upon ergonomics from the outset with a superior grip for its weight.

On the top of the device, the Fiio M15 supports a volume wheel similar to Questyle’s QP1R. However, unlike the latter DAP, the M15 employs a more subtle derivative with an all-black finish. It is nice to see the incorporation of a pulsating LED beneath which works well in low-light conditions.

FiiO have customized a special ‘high-damping’ potentiometer for the volume knob with the aim to prevent accidental turning. One area of improvement could be the placement of the actual volume where it feels more intuitive on the right-hand side of the device (for right-handed operators) which make up the majority of people. Nonetheless, I am impressed by the quality of the volume wheel.

Next to the wheel, the Fiio M15 supports a wide range of outputs including single-ended 3.5mm and balanced 2.5 mm or 4.4 mm options. It is quite rare to see all three of these outputs available in a single DAP and it is good that FiiO are accommodating all cable termination types. The quality of the outputs are equally impressive with a strong concentric ring design.

On the left of the device, the M15 has six physical buttons within an indented groove. The groove indefinitely improves grip as well as serving as a nice aesthetic implementation – another example of style serving function.

At the top is a ‘hold’ switch which when turned on disables the touch panel display. Beneath is the power button as well as three standard playback controls. Finally, FiiO have included a multifunctional prompt button enabling users to ‘Add to Favorites’, ‘Switch songs randomly’, ‘Switch filters’, ‘Enter Bluetooth receiving’, ‘Enter USB DAC mode’ and more.

This is useful feature and allows quick access to common actions. Each button shape, however, is virtually the same with no lack of spacing and hence hard to distinguish from a tactile perspective.

At the bottom of the device, the M15 has USB-C charging capabilities and uses a single SD card slot supporting up to 2 TB of expansion. The card slot requires an ejector key in much the same way a SIM card tray does in certain phones. I would prefer the more natural ‘push and eject’ mechanism that the Lotoo PAW 6000 uses but it is evident to see FiiO go for a more seamless design structure.

The Screen

The M15 sports a 5.15-inch 1440 x 720 IPS screen with a borderless 10-point touch display. The screen quality is fantastic and more in line with a modern smartphone. There is a wide reading angle and the brightness levels work decently in well-lit conditions. In contrast to the M11 Pro, the M15 makes use of Corning Gorilla Glass providing it with much needed protection against the odd scratch and bump.

Although not part of the intrinsic screen specifications, I particularly like the default screen wallpaper FiiO have chosen. It is different and yet very classy; a proprietary graphic showcasing the internals of the M15 in gold lining with subtle spec markings.

The User Interface

The M15 comes equipped with the Android 7.0 Nougat Operating System. For those who own an Android device, this is a familiar and well-trodden user interface which is not only fluid and smooth but highly intuitive.

FiiO, unlike many other DAP companies, have always run their players in parallel to the smartphone user experience. While some may argue this does not differentiate itself enough to define the need for purchasing, others may argue the same audiophile offering in a familiar interface is a much-needed solution.

I fall in the latter camp and after experience with some other DAPs where the user interface could be made more intuitive (such as Questyle QP1R’s and even Cayin’s N8), the FiiO M15 provides a refreshing and yet recognised experience.

The Fiio Music Player app is their stock music app which provides support for MQA and Fiio Link (allowing users to control the M15 directly from their own smartphone). Some other key implementations are gap less playback, play through folder as well as equalizer settings.

The in-built equalizer allows preset genres to be chosen directly (from 20 Hz to 20 kHz) adjusting ten frequency bands independently from -12 to +12 dB dependent on personal listening needs.

Overall, the user interface is very smooth highlighting an importantly functional aspect of the touchscreen. It is nice to see the return of the Google Play Store and the ability to download popular streaming services such as Spotify and Tidal rather than an APK file.    

The Internals

FiiO have gone the AKM route with their latest flagship 3rd generation dual AK4499EQ DACs. With four channels per chip, the DAC can decode up to 768 kHz sampling rate and native DSD512 with a signal to noise ratio up to 140 dB and THD+N as low as -124 dB.

Two NDK femtosecond crystals work in conjunction with the 3rd gen FGPA clock algorithm to provide lower jitter and a more accurate clock for the DAC.

The M15 uses the same processor as the M11 before it – the Exynos 7872. While they haven’t chosen to upgrade the processor, there is not much to complain about as the processor provides a zippy and smooth user experience. It remains amongst the most powerful SoC among HiFi DAPs with a 3GB RAM as well as dual A73 + quad A53 cores.

The XMOS XUF208 USB chip is used to provide info transfer via the USB DAC mode and supports up to 768 kHz/32 bit and DSD512 input. A Qualcomm CSR8675 Bluetooth chip supports two-way LDAC lossless Bluetooth as well as SBC, aptX, aptX-HD, LDAC and HWA codecs.

With flagship-grade gold PCB and high-grade Panasonic capacitors, the M15 looks good on just about any spec sheet. FiiO have really gone the extra mile to not only procure the best elements but to provide immeasurable value as well.

The Amp & Power

The M15 is a small powerhouse providing 490 mW of power under a 32-ohm load and a balanced output power of up to 800 mW. The same 300-ohm load provides 70 mW of single-ended output power and balanced output power up to 275 mW.

To provide uncompromising detail, the M15 adopts 2 high-precision OPA2211 op-amps for the low-pass filter, 4 OPA1612 for IV conversion and 1 OPA1622 for amplification of each channel.

An interesting and new feature is the ‘active servo power’ technology which allows the power output to change dependent on preferred settings. For example, users can decide a minimal noise output or ‘over-ear headphone listening mode’ to driver harder transducers. This is useful for pushing headphones towards the limits of testing but care must be taken not to activate this mode with sensitive earphones (though a warning prompt is made).

The Battery

The FiiO packs in a massive 7490 mAh high-energy density lithium battery which stands at a higher capacity than both the Cayin N8’s 7000 mAh and the LPGT’s 5500 mAh. This provides the M15 with a whopping 15 hours of battery life which places it in par with Lotoo’s PAW 6000 (which to date stands as one of the best battery life within the high-tier DAP category).

The M15 supports QC2.0 quick charging and fully charges within 3 hours. Although not the fastest overall charging time, the large battery size is suspected to account for this.

Sound quality

The sound of the Fiio M15 clearly belongs to the big leagues with its reference, airy and transparent tonality. While the M11 Pro presents a mid-forward and slightly energetic sound, the M15 accomplishes a more refined sonic landscape with a smoother upper midrange and a well-positioned mid-section. It is clear to see that the house FiiO sound still lingers with a slight tilt towards the higher frequencies (particularly upper midrange and lower treble).

With that said, the sound of the Fiio M15 is largely linear with a capable bass performance and extensive treble. It is easier to appreciate sense of space and separation as the M15 does not have a particularly warming low-end. It is a neutral tonality with some hint of brightness owing to the relatively leaner note size, perceived height and extension drawn from the midrange and treble.

An important point to note is that there some difference between the single-ended and balanced outputs with the latter picking up more dynamic range capability with added headroom and bass impact. In this mode, the Fiio M15 really shines and delivers a stellar performance. Micro-detail revelation is equally fantastic with the M15 able to unravel cues and nuances in tracks akin to high-performing desk set-ups. It does so amidst a pitch-black background with ultra-low distortion levels with help from the NDK femtosecond crystals for a jitter free performance.

In “Shame on Me” by Avicii, bass is presented as punchy with texture. It is not a rich sound but digs surprisingly deep for its neutral predisposition. Next to the Questyle QP1R, the M15 presents more punch and articulacy at the expense of the QP1R’s body and mid-bass tilt. One of the critiques of the M11 Pro was its slight edginess, however the M15 does well to negate this with a more polished tonality. Overall, the sound is more open, layered and detailed in line with a top-performing DAP.


Cayin N8 ($3599)

The Cayin N8 DAP and the Fiio M15 are two different sounding DAPs. While the Cayin N8 draws its inspiration from a tube analog sound rich with macro-dynamic prowess and harmonic bloom, the M15 delineates a clearer and more transparent sound. The N8, possesses the larger soundstage with an overall more encompassing sound.

The two DAPs lean on different directions of the analytical-musical scale with the N8 adhering to a richer, slightly softer tonality whereas the M15 focuses on a leaner signature with faster decay. The difference becomes even more evident with the Cayin N8’s tube-mode powered on with vocals expressing the favorable harmonic distortion that tubes are known for.

Despite their differences in signature, both the N8 and the M15 supply reserves of power capable of driving difficult transducers. Needless to say, they express high dynamic range with bass that presents with plenty of slam albeit with different tonal characters.

Lotoo PAW 6000 ($1200)

This has been a long-awaited comparison especially as the two DAPs perform at the height of their performance-curves and retail for a similar price. Both hover along the neutral baseline with the PAW 6000 slightly favoring the bass and lower midrange whereas the M15 has an affinity towards the upper midrange and lower treble.

As a result, the PAW 6000 sounds more authoritative in the lower frequencies and richer because of the lent warmth. The M15, on the other hand, has more of an open sound with added height owing to the more extensive treble. Again, at this price – preferences certainly come to play as well as synergy with certain monitors.

In terms of OS, the two DAPs could not be further apart with the PAW 6000 using a proprietary custom OS and the M15 providing a familiar Android 7.0 experience. Where all the bells and whistles are concerned, the M15 delivers and then some. I am a big fan, however, of the stripped back PAW 6000 custom OS which is blazingly fast and responsive.

FiiO M11 Pro $650

The M11 Pro was a well-rounded DAP which garnered many awards. One point which plagued some users, however, was its plausibly too mid-forward sound. This, coupled, with its propensity for upper midrange sheen may not have gelled with certain combinations. The M15 improves upon this with a more open sound with better detailing and smoother higher frequencies. Dynamic range is also heightened which is likely owing to the increased power reserve and load per ohm.


The Fiio M15, in much the same way as the Cayin N8, caters for a wide selection of IEMs as well as headphones. The ‘over-ear headphone’ is particularly impressive to drive headphones such as the ZMF Verité to enough headroom and scale. Other impressive combinations included 64 Audio’s Tia Fourte and Campfire Audio’s Solaris 2020.


The FiiO M15 represents the most complete and well-rounded digital audio player that the Chinese audio giant have ever created. It is clear to see a lot of thought, structural design and passion has gone into the flagship DAP. To this extent, it is a stand-out performer with an impressive battery profile, versatility, streaming capabilities and most importantly – a top tier reference sound.

No doubt the M15 will take a seat in our best DAPs list and I am sure it will earn many awards as the M11 Pro did before it. Improvements to note could be the inclusion of Bluetooth 5.0 as well as certain software optimizations (particularly volume dB displayed as opposed to volume bar graphics) and a ‘search bar integration’ in menu.

The form factor may not appeal to everyone either as the M15 is relatively wieldy at 310g and prone to slippage – I suspect the inclusion of a protective case would have obviated this issue. Nevertheless, the M15 is a stallion DAP which accomplishes a lot given its price and hence highly worthy of an Audiosolace recommendation.

Fiio M15

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Manufacturer: FiiO

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