FiiO M15S

Having recently tested the new M23 extensively, I was very excited to see how it compared to its bigger brother, the M15s. With an RRP of €999, the M15s is priced slightly above the M23 and directly below the top model M17. As soon as you unpack it, you notice that the M23 and M15s hardly differ in terms of weight and size. However, the more expensive M15s comes with a genuine leather cover, which I would have preferred for the M23 instead of a simple silicone cover. The M15s also comes with a docking station including a cooler on which the DAP can be operated very conveniently in desktop mode. The volume control on the M15s is either classic via a potentiometer or via two buttons, which can be configured as required.



If you take a look at the technical data, the M15s uses the top DAC from ESS, while the M23 uses the top model from AKM. In terms of performance, the M15s is somewhat more powerful with its 2x1200mW@32 Ohm instead of the 2x1000mW@32 Ohm of the M23. On the other hand, the M15s has a slightly more powerful battery. The advantage of the M23 is that the battery can be charged even faster than the M15s. However, it lasts around 1 hour less.

There is no difference between the CPU and the software. Both process touch commands quickly and smoothly - there's nothing to complain about here. A big advantage for me with the M15s is the line out. This can be set not only fixed but also regulated, which is very advantageous for operation with the iBasso PB5, for example, because the fixed line out of the M23 offers hardly any control range for very sensitive IEMs due to the very high voltage. Incidentally, both DAPs will receive Android 12 via a software update.



For the sound test, I used my Focal Utopia 2022 and my Unique Melody Multiverse Mentor. Both devices can be operated effortlessly in low gain and the M15s is dead silent with all the IEMs I have tested! The volume control range is also fantastic and I would also like to have this for my iBasso DX320 MAX Ti, where I always have to readjust the digital volume control. However, headphones that are very difficult to drive, such as a Susvara or 1266 Abyss TC, are too much of a good thing for the M15s. Here you have to resort to even more powerful DAPs like the M17 or an external amp like the PB5.

Tonally, the M15s plays even closer to its big brother M17 than the M23 does. With its AKM DACs, the latter sounds a little smoother, but thinner in the mid-range with a slightly purer bass range. The M15s, on the other hand, strikes like Thor's hammer when the recording demands it. It also has the fuller mids like its big brother, the M17. What is only noticeable in a direct comparison is the slightly wider imaging of the M17. It also separates a little better but also sounds more technical. All FiiO DAPs play on the brighter side and are not comparable with a Shanling M8 (significantly warmer) or 320 MAX Ti (somewhat smoother, but also bright).

The combination of M15s with the Utopia 22 and its dynamic capabilities is a brilliant combination and a lot of fun. The bass goes deep down with more slam than with the 320 MAX Ti, but without lacking audibility. This is ensured by the rest of the tuning, where the transition from bass to mids and treble is seamless.

From a stage perspective, the M15s is more spacious than the M23 with slightly better separation. Individual sound events crystallize more clearly than with the M23, which focuses more on a smoother rather than more technical presentation. Fortunately, the M15s does not produce a boring, technical sound, but a very coherent, very clean, high-resolution and, above all, involving sound due to the great bass range.

The rather bright presentation of the FiiO DAPs already showed in my last review that the combination with the external iBasso PB5 Korgtube amp is a good combination. And the M15s is no different! The Multiverse Mentor in particular gains a little more space in this combination and the overall warmer sound colors invite you to enjoy music for hours on end.

I think you can't go wrong with either of the DAPs M23 and M15s. As I need the regulated lineout for my application and am also addicted to the brilliant bass range, I personally opted for the M15s!

Fiio M15S​

The M15S by FiiO promises to be the middle-ground DAP for portable and stationary use. Is extra power and some cool features enough to secure it a place on the market? Let’s see how much we can extract from the newest DAP in FiiO's portfolio coming at $999.

​

Introduction to the FiiO M15S review​

I had the FiiO M11 Plus ESS (which I reviewed) some time ago and I loved it. Then, I wanted to try something else and swapped it for the Chord Mojo 2. Worst decision ever, to be honest. Got rid of it quicker, than you can say “but why, it’s supposedly so good?”. Not for me. So I went back to using dongles, with the Questyle M15 taking the prime place in my inventory. A dongle isn’t a perfect replacement for a DAP, so I kept looking. Imagine, then I stumbled upon FiiO representatives at the CanJam in London. After a short back and forth we have reached an agreement, and the FiiO M15S has landed in my hands, together with something else, but that’s a story for another time.
Why do I like DAPs so much, and why a dongle can’t replace it you ask? A couple of reasons. I value the independence of music from my phone. Also, listening to music doesn’t drain my phone’s battery. Great for longer trips. Then, the sound quality. Physically larger device means we can put more stuff inside. And in this scale, the more the better. Reviewed FiiO M15S features one of the top DACs on the market, the ESS Sabre ES9038PRO, which by itself is just huge. It by itself is as wide as a dongle I used for comparisons in this review. Lastly, output power. Less important with IEMs, as dongles can handle that very well, but with headphones, extra headroom makes all the difference.

Packaging​

Unboxing feels like it’s a premium smartphone. Or, like it’s the M11 PLUS with extra steps. Everything we get is packed very nicely and securely. The external sleeve is full of iridescent prints. Looks cool, like it’s a gaming accessory.
Inside, we’ll find the player in a hard foam piece. Underneath them you’ll find the DK3S stand with a cooling fan, quick start guide and USB type C/Type C- Type A cables. I like the idea of the stand, as it complements the FiiO M15S as a desktop DAC/AMP. Even without running the fan, it’s just convenient to use, instead of a DAP lying flat on the desk. Reviewed FiiO M15S is delivered with a leather case, featuring a metal backplate for heat sinking. Cool, nobody wants to order that separately, especially at this price point.
So, overall: all is good here, nothing to complain about.

Build Quality​

The first thing you should do when unboxing this DAP is to take it out of the case it comes in. The build quality is immaculate. I dare you, to find something imperfect.
It’s okay, I’ll wait.
Told you.
It looks great: metal frame, with perfectly fitted front screen and back glass. Tactile buttons, smooth knob on top, and a necessary hold button. The top knob is specially braced in case the DAP drops on top of it. It should survive that incident, but I haven’t tested this theory. I have a strict don’t drop stuff policy, but you can try if you want. Thermals are really good too. The internal heat spreader works nicely, heating the chassis pretty evenly, though the lower part is slightly warmer. Nothing worse than accidentally touching a hot spot on a DAP or smartphone, am I right?

Tech​

Reviewed FiiO M15S is a DAP, which means this is going to be a long paragraph. Let’s start with the system part, and then we will finish with audio-related topics. The first thing we see is the 18:9 5,5” 720p display. While it’s nothing to write home about when compared to contemporary smartphones, it’s still a solid display. Vivid colours, brightness and resolution are enough for usage. To be honest I thought it was a higher resolution. Good thing I don’t review video gear then.
The brain of the reviewed FiiO M15S is the Snapdragon 660 featuring 4x 2,2GHz and 4x 1,8GHz cores, with an Adreno 512 graphics core is an older, but still capable SOC. It’s been used in phones like Xiaomi Redmi Note 7s, or Samsung A9. It uses 4GB of RAM and has access to 64GB of internal memory (some of which is taken by the operating system). The memory can be extended with a micro SD card, of a capacity of up to 2TB. Since no reputable brand makes cards this big, we’ll have to stick with a realistic 1TB, which is still absolutely insane.
All of this tech runs on a custom Android 10 with global SRC disabled. It means, it basically is bit perfect regardless of what app are you using. As was pointed out by my friend, Grzesiu, an older Android is not as secure as the newest versions with current security patches and features. Something to consider.
Built-in BT is done with the Qualcomm QC5124 Bluetooth 5.0 chip. It allows to use of the nicest codecs like LDAC, aptX HD, and AAC in both ways: as a receiver and a transmitter. On board, Wi-Fi supports both 2.4GHz and 5GHz bands in a Wi-Fi 5 spec. The power for all of that goodness comes from a 6200 mAh battery, which you can top up in around 4 hours, thanks to QC3.0 and USB PD.
Dope. You can set the battery limit at 80% to extend its life, a great feature! Nothing more annoying than searching for not only the right battery but also a repair shop that will handle a DAP a couple of years from now.
For the audio part, inside the reviewed FiiO M15s we have a proprietary digital filter/SRC stage using an FPGA with a femtosecond oscillators from the Japanese NDK company. It also produces the SPDIF output you can access via the 3,5mm jack. The D/A conversion is done with an ESS Sabre ES9038PRO. Yes, the full-size version. It is interesting to me, how they managed to fit it inside this DAP. Kudos to that, not an easy task.
The analogue stage uses OPA927 opamps. The audio chain uses high-quality thin film resistors and metalized foil caps from Panasonic. We are getting a set of standard outputs: 3,5 mm and balanced duo: 2,5mm and 4,4mm. The first one can work as headphone out, line out and SPDIF out. Balanced outputs are either pone output or line level. A great feature for integrating the reviewed FiiO M15S into a stationary system. The USB connector works both ways allowing this unit to either feed an external DAC or become a USB DAC itself. The HiRes functionality is here with capabilities of up to 32bit/384kHz and DSD256. Is it the most you can get nowadays? No. Should you be bothered by that? Oh no, I won’t be able to listen to my collection of 768kHz music. Which is one sample file, which I never actually played.
The power output is respectable, with up to 1,2 W @ 32 Ohm @ 1% THD @ balanced out in Ultra High Power mode. It isn’t available for portable use, where we can expect a pretty nice 1 W @ 32Ohm @ 1% THD @ balanced out. Around 800mW with a reasonable distortion. A bit more than half of that with single-ended output. More than enough for IEMs and headphones. It’s not like I’m commuting to work with Susvara on my head, let’s be realistic.

Desktop mode/high power

Charging the reviewed FiiO M15S is not as easy as you would expect. Let me explain. When connecting a regular USB power supply, it will charge like any other thing on this planet. But, if you plug in a fast charger with QC/PD functionality, you will get some extra options. First is the Desktop Mode. It disconnects the battery completely (neither charges nor drains), meaning the USB power supply takes full responsibility for the device. It basically turns into a desktop device. If you use the M15S at home it will hugely extend the battery life.
The Ultra High Power Mode uses external power to increase the voltage rails from +/-6V to +/-7,6V bipolar, giving us around 3V of extra swing. It means that we have more headroom for the DAC part and more output power for the headphone amplifier. It’s an absolutely brilliant idea and it gives it more edge against other DAPs in stationary roles. Also, unlike its older brother, the reviewed FiiO M15s has no external power brick required. Just a modern USB power supply, which you most likely already have. How does it affect the sound? It is easy to notice. The music feels more dynamic and open. Sound staging gets wider and bass gets a nice boost. When listening at home, using this mode was a no-brainer.

User interface/features

The operating system of the FiiO M15S, being a custom Android 10 will feel familiar to most of us. Navigation is very intuitive as usual. All of the important settings are available in the easily accessible top menu. This DAP offers us 5 modes of operation:

1. Android Mode: Regular, Android-based DAP with access to Play Store and 3rd party apps.
2. Pure Music Mode: skeleton OS functions and only the FiiO music app is available. Shuts down unnecessary processes and programs in the background. The “Audiophile mode” if you may.
3. USB DAC Mode: exactly as stated (volume works?, HID?)
4. Bluetooth Receiving Mode: turns it into a BT audio receiver, and shuts down everything else.
5. AirPlay: works as an AirPlay receiver. Duh.

Most of my listening tests of reviewed FiiO M15s were in mode 1.
An exciting feature for me is the FiiO Roon, which turns the reviewed FiiO M15S into a Roon Ready streamer. Works flawlessly, there is even an icon of this DAP in Roon. A fantastic option for those who want to share this device between home and portable use. As an avid Roon user, I’m content. Also, the buttons on the player control Roon, so you can easily skip tracks.
The menu holds another audiophile feature: upsampling to DSD64 2,8MHz. It uses the built-in FPGA to convert every input to DSD before it is converted by the onboard DAC. Besides “cool kids factor” it makes the sound a bit softer, smoother and slightly less dynamic. Also, drains a battery like crazy, so be mindful of that. Cool thing to have, similarly like it was in the M11 PLUS.
There is one multifunction button on the side. By default, it allows for quick mode selection, but you can customise its function, including switching filters, adding to favourites, switching songs randomly and a couple more. A convenient thing to have, but when using the switch filter function I was getting no info on which filter I was using. I would have to go into audio settings to check which one is being used now. Shame, it’s not displayed anywhere else. Nothing a patch won’t fix FiiO.
The last trick I want to talk about is the second harmonic regulation, a feature built into the ES9038PRO chip. It allows us to increase the amount of second harmonic in the output signal. Make the sound more tubey and sweet. In practice it felt like a bit of extra compression, softening the sound and dynamics. I preferred listening without it, as level 1 was hard to notice and level 2 was a bit too much for me.

Sound of the reviewed Fiio M15S​

To kick things off, FiiO M15S sounds different than most ESS-based audio devices. So that’s exciting (at least for me). It has a focus on midrange, pushing it forward. The exact opposite of a V-shaped response. The first things that came to mind after listening to it were spectacular sound staging and dynamics, which I admit sounds like any other review about gear with ESS DAC. I know. Not much I can do about it. On a more serious note, the sound quality from the M15S is spectacular for its price. It was able to stand up to a few really good competitors in portable and desktop realms.
Bass
When we think of ESS Sabre devices we usually think about spectacular bass. Well, not in this case. It plays a supporting role, taking a backseat. It provides enough quantity to provide a foundation but certainly is not a star of the show. It provides a solid level of resolution when listening to Afghan Whigs – Gentlemen. The bass riff in the background is crisp and separated from other instruments. Drums were tight, and snappy, with a great natural reverberation. Something I like a lot in sound. The textures are on point and while the bass sounds a bit light to my taste it does deliver quality noise.
Mids
This is where the party’s at. If you like huge, bold vocals and guitars, you’ll be delighted with the reviewed FiiO M15S. It puts the midrange on a pedestal and pampers it to no end. It is the most prevalent with vocals, both male and female. The singers/rappers/growlers seem to be physically imposing and they speak to like you are the only person in the world. I don’t want to ride the hype, but I can’t mention Oliver Anthony’s Rich Men north of Richmond. If you listened to this song even once, you know that besides hitting the nail on the head lyric-wise, it also is recorded very poorly. Nosie, clipping only adds up to the message. It fits with him being an off-grid artist, recording on a field outside his home, singing his heart out. It makes sense. And when you listen to it on the M15S, it speaks straight to your soul. As with other ESS-based DACs, the tonality could be richer (like men north of Richmond) it still is an excellent display of capability, especially if you love the clean, uncoloured, exact presentation.
Treble
I’ve been listening to Robyn’s Missing U, which has a lot of bells and I have noticed that they really stood out to me. The M15S treble is terrific. It blends resolution, speed and precision while not falling into metallic quality which can happen with ESS-based DACs. Bells in the mentioned song spread out all around my head evenly, creating a really immersive performance. They are a bit behind midrange, so take that into consideration when selecting your headphones/IEMs, more on that later. All in all, the FiiO M15S reproduces treble with great vigour, highlighting its detail.
Sound staging
Sound staging is very impressive here, although it has some quirks to it. Let’s start with the elephant in the room: vocals. They tend to be set dead centre with a tendency to be very big in size. It empowers the vocalists’ performance to a huge degree. Listen to Stir it up by Bob Marley & The Wailers, you’ll understand what I mean immediately. Bob and the choir are slightly exaggerated, while the rest of the bands feel very natural with a very wide and decently deep soundstage. The deepness seems to be limited by the dominating midrange in the middle. It creates this uncommon, but very fun vocal-centred presentation.

Comparisons​

Sadly, at the moment I only got my hands on ESS-based devices, so the differences aren’t going to be that big. There is a lot in common between those. I hope to expand my choices in the future, but for now, it is what it is. It’s also a great mirror of how the market was shaped by the fire of the AKM factory. To end on a positive note, I’m excited to see that Cirrus Semiconductor is still a pretty popular choice, AKM is getting back into the game, and we have a new player in the audio DAC game, namely ROHM from Japan.

FiiO M17
The difference between those two was much bigger than I was expecting. I was thinking: same manufacturer, same chip… Well, FiiO said hell no! The M17’s sound signature is a v shape with extra emphasis on the bass. It’s big and thick, just like me. It’s a big contrast to reviewed FiiO M15S’s midrange forward sound. The bigger brother does sound better, but is it “I’m going to carry this brick around like I’m a slave in a quarry? Don’t know. If I was travelling a lot, and staying in hotels a lot… Yes. It would be my audio centre, able to perfectly drive regular headphones with its superior output power. In my case, travelling to work, or domestically (and not that often) I prefer the FiiO M15S. It is still a great desktop device if need be, but has a much better carry-ability factor. It fits into either a pocket or a fanny pack.
The M17’s bass is much more prevalent and dominating. It does that while preserving the control and resolution of its younger brother. It’s going to knock your socks off, and you’ll come back for seconds. The midrange is my opinion a bit less pleasant than in the FiiO M15S. Smaller DAP has more finesse and agility. Human voices seem more open and engaging. The resolution and scale are once again on Big Boi’s side. To top things off, treble is similar in both cases. The M15S might come across as slightly metallic, while the M17 is much more neutral and less offensive.

JDS Labs Element III

As you know, I was really impressed with Element III’s mature sound and great feature set. It felt only right to compare it with the reviewed FiiO M15S in desktop mode, after talking so much about how it functions. So, I put the Ultra High Power mode on and switched to 3,5mm connectors to even the playing field. For ease of you, the JDS takes the point. A simple, fast user interface provides everything you need in 2 or 3 moves of a hand. With the reviewed FiiO M15S it takes a bit longer, because of how many functions there are. Speaking of which, the DAP takes the point here. While EIII is only a DAC/AMP, the hero of this review does everything from BT, AirPlay, local files and streaming. And is a solid DAC/AMP on top of that. Sound-wise, the M15S takes the cake. It is clearly a superior-sounding device. While the EIII has a more balanced, universal sound to it, the competitor takes the whole thing to the next level. Might be the jump from portable ESS9018K2M to major league ES9038PRO. The DAP provides more resolution, more open sound, and better sound staging. It also has its own style which might be a pro or a con. Depends on you. In terms of driveability, the EIII can do more, but in most cases, the difference wasn’t huge. Of course all of the extra options and better sound cost more.

Questyle M15

I had to compare the two. First of all, a dongle vs a DAP is a discussion that never ends. The Questyle’s dongle is one of the best on the market. Secondly, THE COINCIDENCE: Questyle M15 and FiiO M15S? Come on, I couldn’t let that pass unnoticed. So, do the differences justify the price jump between the two? The answer is not so straightforward as yes, or no. It comes down to your needs and lifestyle. Is the reviewed M15S a reasonable choice for people who use IEMs on a commute to work? Unless you are chasing the last ounce of sound quality – probably not. On the other hand – if you travel more, or use it in your home system, the extra investment seems to be a no-brainer.
Sound-wise the DAP is significantly more capable – which shouldn’t be a surprise to anybody. The dongle hides detail and feels a bit choked up in comparison. The dongle does better in terms of the amount of bass, which might be a deciding factor, for those, for whom the M15S feels too bass-shy. To be fair when I listen to the M15 it feels like it’s a great sound and I don’t miss anything. Then, when I switch to the M15S… Yeah, there it is.

Pairings​

Meze Liric

Meze Liric is considered one of the best closed-back headphones on the market and you can’t understand how much I wanted this set to work. Super comfortable headphones, with a capable DAP, it had to work. Well, it doesn’t exactly. The Meze’s child has a tendency to be shouty around the mids/treble border. The M15S like to push the midrange forward. It gets shouty and sibilant on some tracks. Too much for me to be honest. Imagine how heartbroken I am, when I wanted to buy the Liric for personal use with this DAP. Sadly, while both are great products, they aren’t made to work together.

Craft Ears Aurum

The previous flagship from Craft Ears, the Aurum is a great match to the M15S. Its slightly V-shaped response matched the M15S character. Together they make an amazing set in which the midrange still dominates but it is compensated by punchy bass and crisp, fresh highs. It’s a very fun-centred setup, which shines in all genres. The notable moment for me was when I was listening to mentioned earlier Rich Men north of Richmond. The effect of his raw voice was multiplied by this combe to a bone-chilling effect. A truly spectacular show of capability.

HiFiMan Sundara Closed

While not exactly portable, the Sundara Closed is a great headphone. After my disappointment with Liric, it was my next obvious choice and boy it didn’t disappoint. Together with the M15S, it presented a fresh, surprisingly open sound. Lighter tonality and excellent tight bass are the name of the game here. I love the detail retrieval from this combo. The M15S drives the Sundara Closed with ease, even without the Ultra High Power mode on. With it, it’s even better. Both work great even at louder settings, with no lack of headroom. No choking up, just music. It’s a testament to a great amp that is used in the M15S.

Fiio M15S Review – Summary​

Well, what can I say? Another really good DAP from FiiO. The value for price is very strong here. We get a terrific sounding source, that can handle any IEMs and many headphones.
Its sound signature is midrange-focused with excellent resolution and dynamics. On top of that, we have a set of thoughtful features that actually make a quality of life difference. Battery saving, extra power with USB PD/QC chargers, multiple modes dedicated to different uses. I can see the M15S becoming a part of many people’s lives both at home and outside. If you are in a market for a capable DAP, give the newest FiiO a shot. It’s worth it.

Recommended.

Big thanks to Fiio for providing the M15S for this review. I wasn’t paid or asked to say anything good or bad about this product, all of the above is just my personal, unbiased opinion.

I have had a long-time relationship with FiiO. Not that the brand knows me by any means, but I have been a user of their products for a long time. I started my audiophile journey with their basic M6 music player years ago. But after using their M11 Pro series of DAC/AMPs I kind of drifted apart because I was not a fan of their THX implementations, they sounded lean and dry to my taste. But time came back and I got to try their current flagship M15S audio player courtesy of a school friend who bought the unit from HPZ. After spending a good 1.5-2 week period with the player, I feel I should make some short impressions and then a video review later this week and then the unit goes back to my friend.

Build Quality:-

FiiO offers good build quality, the DAP is a little heavy but nothing much to worry about. It is one of the few players in the market or I should say one of the few new-generation players to feature a 2.5mm balanced output(not that matters to me, but some people still have 2.5mm terminated cables). Build-wise it is really good and feels premium and solid. The back side has a glass finish with a 3D style pattern, a solid one I would say. Also, we have a leather case in the package and also a fan to keep the device cool you know for serious situations.

Sound Impressions:-

I am coming back to FiiO Players after a long time. Like after 2 years or something and that too with their current flagship “portable” music player. I tried to talk to people to get an idea about the M15S sound so that my friend could make an informed decision. But I was not getting proper impressions from anywhere apart from some reviews online with most stating that this one has a detailed sound presentation. But nobody told me so many things or maybe I didn’t watch them properly? Well, here are my impressions.

First and foremost, the FiiO M15S is nothing like the M11 Pro series, I mean yeah it’s an upgrade to that series, and a flagship for that matter, but the difference is easily noticeable. It’s not lean, it’s not dry per se, but it is very very very clean. There is no audible noise floor even with sensitive IEMs that I tested during this period. I am happy that the pair isn’t lean, but hey don’t expect Sony Wm1A MK2 level richness, it is not that rich but not lean either, hits the sweet spot I would say. M15S has a balanced sound mostly, I don’t hear any frequencies getting more pronounced or something. And It’s very resolving, like the detail level is simply astonishing, and the technical parts like imaging and separation are on the ultimate level. I would rate this even above my recent WM1A MK2 in terms of technical performance. The soundstage also has a good 3D feel to it, it feels spherical, it is wide and deep.

The bass part is quick and punchy, It is not warm per se, it has a solid and tight response. The midrange is deadly accurate, I mean the clean background helps in popping out the details and vocals with ultimate performance man, simply stole my heart in the first listen only. Treble is a little sparkly but nothing to worry about, it feels lively and pushes crisp details(not fatiguing or harsh unless and until your IEM is too bright that it needs a warm source to balance out). Timbre-wise, I would say the FiiO M15S mostly have a transparent and neutral timbre approach when coming directly from Sony WM1A MK2 it feels a little dry in comparison, but I can’t call it dry at all. It has that neutral and naturalness to the notes and vocals that it doesn’t feel dry or analytical to me. In Sony’s offence, it’s rich as honey my friends everything feels dry after Sony lol.

Another point I would like to mention in favour of M15s, the player is astonishingly powerful. Like man, it is too powerful for IEMs, I never had to go above medium gain for any of my IEMs and that too at a maximum 30-50 volume level out of 120 available. For my Sennheiser HD660S2, I tried using Ultra-high mode and still never had to push the volume much(like 30-40/120 only).

Now on to some pairing impressions:-

FiiO M15S with HiBy Yvain:-

HiBy Yvain is a multi-BA upcoming IEM with a neutralish sound. It pairs amazingly well with the M15s, the details are good, instruments sound crisp. I find the Yvain to be a bit bright in treble and the transparent nature of M15S brings that out. It’s an amazing combo with the M15s, the resolution, the clarity are top-notch. Although I must add, its bright nature makes the treble a little snappy and crispy, probably overly crisp for me. So I like the Yvain more with my Sony WM1A MK1(modded) which provides a smoother treble.

FiiO M15S With Night Oblivion Butastur:-

Butastur is my new love, this pair sounds astonishing, like ultimate level details, and ultimate level clarity and the FiiO M15S just brings the performance best out of this IEM. With my Sony WM1A MK1(modded) I feel the bass gets overly warm for this IEM, but the neutral and transparent nature of the M15S doesn’t exaggerate that and provides exceptional performance. Imaging and Separation are also super solid!!

FiiO M15S with D’S Audio Fire Phoenix:-

What can I say about this combo, it’s like the perfect flagship-level combo, we have perfect bass, have lively midrange, and a nice and crisp treble response. Sounds really good for different genres.

FiiO M15S with Gizaudio x Binary Chopin:-

Chopin is an amazing IEM man, it has a slight W-shape profile as per me, has a good bass response, a lovely midrange with forwarded vocals, and extended crispy treble. The combo with M15s showcases sheer quality with amazing resolution and details. With my Sony the set isn’t this resolving, technical performance with the M15s is also better in comparison.

FiiO M15S with Sennheiser HD660S2:-

FiiO M15S is the only DAP with me in recent times that can drive the HD660S2 well and on its own only. Previously I had the R6 Pro II+A&K PA10 combo, Sony WM1A MK2 and PA10 combo, but nothing reached the driveability of the M15S I would say. Basically, it feels more lively here on the M15S and is also my go-to setup.

FiiO M15S with TGXEar Sunniva:-

Sunniva, oh my lovely lovely earbuds, they pair so amazingly well with the M15S. These are quite demanding and have an impedance of 180Ω. Previously with my R6 Pro II and PA10, the combo was good for Sunniva. But the M15S here single-handedly drives the Sunniva well. It enables the pair to produce clearer sound, the mid-bass bump is a little controlled although still noticeable neatly.

Now some comparison time:-

FiiO M15S vs HiBy R6 Pro II(My last DAP):-

>R6 Pro II has newer software and a newer processor. It’s more fluid and faster in terms of UI performance.

>M15S has an older Android and also has a 720p display while the R6 Pro II has a 1080P crispy display screen.

>FiiO M15s is a lot more powerful in terms of driving force. It is more resolving and natural as well.

>Technical performance on the M15S is better than the R6 Pro II.

>The R6 Pro II has more width to the stage, but depth-wise it is very lacking, while stage width is not as wide as the R6 Pro II, but with better depth, the M15S definitely sounds more 3D.

>R6 Pro II Treble is less sparkly, M15S feels more energetic and extended.

FiiO M15S vs Sony Wm1A MK1 With Mod:-

I currently have WM1A MK1 with Mod as my main player here are the basic sound differences between the two.

>M15S has more resolution and dynamics to the sound. It basically feels more lively.

>Sony sounds richer and has denser notes for instruments and vocals.

>Sony sounds smoother, it is more suitable for bright IEMs, atleast for me.

Some Basic Information about FiiO M15S:-

>Battery Life of the M15s is marketed as 10.5 hours, in my experience the player lasted for about 8-9 hours using medium gain, streaming on Apple Music, and balanced 4.4mm output. I think we will get about 10 hours with offline playback.

>The Android is a little sluggish compared to the R6 Pro II, but does the job. I don’t notice much of bugs, the new FiiO Application is also quite good.

>Streaming Apps work fine, no issues using Tidal and Apple Music. In fact, FiiO has an app installer application that automatically downloads and installs apps such as Tidal with one click. It is special for us as Tidal is not available on our Google store in India.

>It gets a bit warm but nothing like Shanling M7 level warm. But hey we also have a fan, so use that.

>Ultra-high gain mode is probably useless for me, I never had to go above medium gain, even with my 300Ω headphones(yeah they are not very hard to drive but still), the M15S works well in medium gain only just with some volume gain(like 70-85/120). Let me remind you we don’t have 4 gain levels, we actually have five, Low, Medium, High, Super High, and Ultra High. Ultra-high was probably not required.

>Another point I want to add is that the M15S has two ways to adjust volume, wheel and keys. But surprisingly we can choose only one of the two. Like either use only the Wheel or use the keys only.

Final Words Before I Bid Goodbye:-

FiiO M15S is something I will recommend to people, for me M11 Pro and Plus were not good enough. I even tried the M17, but still found it to be edgy and sharp in treble, Maybe I am more sensitive? But coming to the M15S, I am happy that my friend got it. I will look for a portable Android-based player for myself next year and for 999$, this one is a good choice with a few shortcomings like older Android, slightly sluggish UI, and not that many complaints in the sound quality part. Well, that’s it. I hope you guys enjoyed this blabbering of mine on the FiiO M15S, I will make a final video review probably on Sunday and then this unit goes back to my friend.

Sayonara!!