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!!

This is a brief summary of the FiiO M15S review as published in ichos-reviews website.



Executive summary

The FiiO M15S ($999) is the successor of the FiiO M15 which used to be the company’s flagship. The sweet spot in their catalogue since the M17 is $1799 and the M11 Plus ESS is $699.

The FiiO M15S uses one piece of the flagship ES9038PRO DAC chip from ESS and dual OPA927 for I/V conversion paired with dual OP1612 for low-pass filtering and dual OPA926 for current amplification. The power output of the M15S is as high as 1200mW+1200mW/32Ω from the balanced output in ultra high gain which is exclusive to DC power and 990mW+990mW/32Ω when running from the battery.

In contrast to the FiiO M17 and Q7 where an external DC power adapter is needed to unlock the DC desktop mode, for the FiiO M15S the only thing you need is a fast USB charger with a USB type-C cable. When DC mode is enabled, the M15S will stop charging to preserve battery life.

The M15S inherits the classic, minimalistic FiiO design with the rounded edges and the slim chassis while it is relatively compact and lightweight enough for a flagship DAP which supports DC mode. Build quality, finish and assembly are excellent.

The FiiO M15S uses a snapdragon 660 SoC which is paired with 4 GB of RAM and 64 GB of ROM that effortlessly run a heavily customized Android 10 OS. The M15S is fast and responsive while the 5.5″ display has vibrant colors and excellent visibility.

The FiiO M15S has plenty of power to run most full sized headphones both from the battery and DC modes while the noise free background makes it suitable for very sensitive IEMs.

The sound signature of the FiiO M15S successfully combines the famous ES9038PRO technicalities with plenty of musicality and an excellent tonal balance. The M15S is the warmer and most musical sounding player ever made by FiiO.

Simply put, the FiiO M15S is the best player ever made by the brand and easily ranks as one of the best digital audio players in the market with an outstanding value for money.

To read the full review with detailed sound impressions and comparisons please follow the link at the beginning.

FiiO M15S

I am going to start this review with a bit of a background of what I do and why I choose the gear I use for reviewing IEMs. Most folks know who I am and the community I belong to at headfi.org. I started one of the most popular threads on headfi.org simply called the Discovery thread. You can read the over 5K worth of pages here. This single thread has got the patrons of the thread including yours truly to “discover” what is new and fresh in the industry and while the subjects of the thread are mostly IEM based. We pretty much banter about anything related to audio and our crazy hobby. That thread is still going strong as ever and what got me to start reviewing gears was that people were always asking me to compare an IEM to another IEM and I was always posting my thoughts about a new IEM I would gladly buy with my own money. This constant posting about what I am hearing eventually got me to write reviews on headfi and here I am writing yet another review but this time of the new Fiio M15S.

So what does that have to do with the Fiio M15S? In reviewing more IEMs than I can count. It is all about what the IEM is doing and not so much what the source is doing. Sure there is always the aspect of synergy when it comes to our sources but I needed a source with enough power, battery life and neutrality to where the IEMs connected to it would clearly show me what the IEM is doing, how it actually sounds. How much treble mids and bass was involved, what type of tuning and its technical ability ect. I own a lot of sources and amps due to this reason alone. A bit too much if I am being honest but in figuring out what sources work best with the IEMs I am reviewing. I was looking for a source that would play extremely well with all manner of phones I would review. 3 years ago I found that source. It was to me the most uncolored sound yet clearly dynamic in the former flagship Fiio M15.

Each company that makes a DAP or dac/amp has a tuning angle and so I was searching for the one source that I can easily take with me to work, use it during lunch breaks to evaluate the IEMs I am writing about. Out of all my sources it was the M15 that got the most usage. It is for me the most uncolored neutral yet dynamic sounding source I have ever used and hence a much needed reference tool for evaluating IEMs. 3 years later and granted the battery is not as stout as it once was, still charges to 100% and plays all my music as good as it ever did. When the news broke about the new M15S, I told myself. I gotta get one, plain and simple.

So here it is, the new M15S. With that I would like to thank Fiio for providing the M15S for the purpose of a review. You can read more about the new M15S on the official release page here. My method of testing sources is based on trying it out with numerous IEMs and headphones to check out a consistency for its sound performance and usability. Which is what you will read about on my review.

Proof that Fiio listens to their customers and always improves. The new M15S comes with a very nice form fitting leather case with heat dissipating grills out back, right out of the box. Most DAPs nowadays you get some screen protectors and a plastic sleeve type case at the most but an included leather case already on the player is a novel idea. It is something most folks buy as an added accessory to protect your precious anyhow, so why not throw it in? The old M15 came with a very nice wood box. This wood box will get the collective Oooos and Aaahs of the person that opens the package and then you are left to buy an aftermarket case for the M15. Useless is the word that comes to mind. The M15S thankfully foregoes the wood box but now comes with the one accessory that is a 100% must. The leather case. Fiio gets an A+ just for this included case. You can brag all you want about how nice your players are, but did you get a nice case to go with it? This should be the industry standard as far as I am concerned. Don’t give me a useless fancy box. Give me a form fitting protective case! Then they added a stand fan called the DK3S. That was also included with their flagship M17 player for use when activating desktop mode. The most power output from the player when connected to a power source. It is simple, more power = more heat so the need for external cooling. Again a nice touch by Fiio. The remainder of the accessories includes two sets of cables a USB-C cable and a USB-A adapter and a thinner USB-C - USB-A cable to use with the fan only.

A minor negative I noticed about the new M15S is that your other USB-C cables might not charge the M15S correctly. If you connect an insufficient cable to the M15S to charge it, it will just blink like it wants to charge but not actually charge. Using the included cable is the way to go always. Then there is the battery of the M15S itself. It's got a physically smaller battery vs the former M15. 7490mAh with its real world usage at about 13-14 hours. The new M15S uses a 6200mAh battery with a real world usage time at a more modest 8-9 hours.

Why the smaller battery? It has to do with the more powerful output and a more robust power supply of the M15S to achieve its reported 1,200mW @32 Ohm per channel in balanced out via desktop mode leaving less room in the case or a larger battery. That my friends is a stout output for a portable player. So you're sacrificing some extra battery life for more power via desktop mode. A good compromise? The unit itself on battery has 4 different gain switches and a 5th when connected to a charging port.The 5th gain is apply called “Ultra High” this is the reason why it needs an external cooling fan. Much like the flagship M17 the M15S can be used either portably or at home or office connected to more power. The M15S was designed with a smart charging function where it can auto detect the type of charger you have connected to the M15S and charge accordingly. While on desktop mode you can bypass the battery altogether. Smart charging gives an optional function where you can put the max charge at 90% of full capacity when in portable mode to maximize the battery life span.

The new M15S physical dimensions are as follows. 140 x 80 x 18.9mm or 5.5 x 3.1 x .75 inch. Weighs in at 345g. Equivalent to a thinner brick. It's got similar dimensions to a modern day larger cell phone but thicker with much more substance. It does have some weight to it but nothing that will cause any type of muscle fatigue. Certainly pocketable be it a larger pocket or a carry pouch. It's using a large sharp 720p vivid 5.5inch HD 2.5D curved tempered glass with excellent color saturation, a clean black background with good but not great brightness, a clear improvement from the prior 5.15 inch screen of the former M15. Fiio did not provide a plastic film for the new screen for several reasons. While this screen is not the gorilla glass of their former M15. I am very confident in saying you can forego the flimsy plastic film to protect the screen from scratches. Fiio has confirmed that the screen is durable and will not scratch so easily as it is tempered glass. I have used my Fiio M15 for 3 years, thrown in my pockets and in my bags without any type of scratches whatsoever. I would assume it will be of a very similar toughness for the screen used on the M15S.

Internally the M15S is based on a tried and true now about 7 year old Qualcomm 660 snapdragon processor with Android 10 for its operating system. Also utilizes a QCC5124 for Bluetooth 5.0 compatibility. The Sound design comes from a single desktop ESS ES9038 pro DAC chip and two units of OPA926 for amplification. You can read the specs of the M15S here.

UI and usability.
I can understand why people want the latest and greatest processors and OS for android stuff. I get it but folks always complain about the latest fastest processor and android version for these audio players. OK so it costs $1,000. Are you looking for the latest smartphone or are you looking for a music player? Are you looking for a media tablet or a music player to enhance that media tablet with proper sound? The M15S is a music player which utilizes a faster processor and a proper OS that allows you to have the latest software for online and offline music listening. There is a difference there. Yes the processor is outdated and so is the operating system, however if you are talking about speed and being able to run any music app available today, last time I checked Android 10 and the Snapdragon 660 can run circles for any music program and be very quick about it. If you must, you can look stuff up via the web and use it like a smartphone but let's get real. No one buys a dedicated Android player like the M15S to play games or browse the web with, that is not what the Fiio M15S was made for.

If you accept it for what it was meant to be and the fact that it has no limitations on any music service or way of listening to your music at all, then you will appreciate the hardware used for its sound and its performance. The M15S boots up and plays in less than 20 seconds fairly quickly and is extremely responsive when browsing my music files with no lag issues or slow downs any time I have used it. Sure it would have been nice to have Android 12 and upward but so it would be a bit more future proof you say? By the time Android 10 is obsolete you're going to have to upgrade the M15S in its totality anyways. I bet the battery will wither away before Android 10 will be obsolete. I personally have no issue with Android 10. It's not the Android 7 that is being used on the old M15 so I am ok with it.

M15S has 6 different operation modes preloaded. Fiio exclusive mode: is what I use the most with my preloaded 512 gig memory card. Android mode for downloaded programs to use for the M15S, Spotify, Amazon music, Qobuz ect. Airplay mode for iOS devices. USB dac mode when you feel your phone or computer just isn't cutting it for sound quality. Bluetooth receiver mode with all the latest high res codecs including LDAC and APTX HD ect. Just in case you want to connect to your device via bluetooth for some wireless high fidelity sound. And lastly Roon ready.

I have to apologize to my readers for not testing out Roon as I don't have Roon at all. I own Flac and MP3 versions of more CDs than I can count of my music so that's where I get my music. I did read an online publication where the reviewer tested out Roon here, this guy was testing more of the android and functionality side of the M15S more vs its power and sound. I know it's not good form to refer to an outside review for parts of my own review but in this case, you will get a good idea of how Roon works with the M15S in this read. I felt it was pertinent to cover the basics of the review for the M15Ss full functionality including Roon. I don't have it and don’t use it at all so might as well refer folks that are interested in it to a person that does using the M15S. My review here is more based on how the player performs, usability and its sound quality. Onto the read.

Operating the M15S is snappy and intuitive, especially if you already own any other modern Android device of any type. Fast with a nice large clear colorful display, connecting to the internet is easy enough via 2.4/5Ghz options and will bring some extra functionality to the M15S. Bluetooth connection is done via Qualcomm QCC5124 chipset with two way functionality.

Testing the new Fiio FW3 and Fiios BTR7 yielded excellent results and a very stable connection to both TWS products and at a good solid 30-50 ft away from the M15S without breakup depending on indoors or outdoor usage. Connecting through bluetooth to use as an external sound card for my laptop also worked impressively well with excellent sound quality to boot. I do prefer the USB connection as this brings the best sound quality via computer or tablet out to the M15S but bluetooth is a simple way of using the M15S for an easy upgrade for sounds from your devices.

Beyond the extra steps Fiio did to make sure all the power the M15S didn't melt down the player or bloat the battery. Graphene heat dissipation technology, high thermal conductive gel and a stainless steel battery compartment. Engineering a proper player is more than just a speedy processor and the OS to run it. Extra attention went into the shielding for zero external noise or interference. One thing is very clear about the M15S. It has a supreme richer dynamic sound quality with a clean black background and yes, it is an upgrade in sound and power from the M15. Will get much more in detail in the sound section of my reader later on.

Physical button layout makes a bunch of sense and this time around includes a nice RGB light indicator at the base of the analogue volume knob at the top right of the player that changes color based on the type of music files you're listening to. Fiio is not shy about using the RGB lighting, in fact if you own a Fiio source nowadays, without it, it might be an older product. Next to the volume knob on top are the 3 types of phone plugs, center is 4.4mm a 2.5mm next to it and lastly the standard 3.5mm jack on the left top portion of the player for your headphones and or line out. When placed inside a larger pouch or pocket it is easy to operate without looking at your screen. There are also physical volume buttons located to the right side of the player. Specifically a hold toggle which is a good option so you don't accidentally forward to the next track unintentionally. Below that are volume buttons up and down with a multifunction button at the bottom.

On the left side of the player are the music control buttons. Top to bottom. Power button, previous track, play/pause, and next track. This layout of buttons all with good functional response make navigating music just that, functionable with no fuss. Having two ways of controlling volume is a welcomed design choice as I end up using both and aesthetically the RGB coloring in the bottom of the analog volume wheel is a nice touch. Bottom of the device has its USB plug for charging or connectivity and next to that is the card slot which is similar to your android phone's memory card slot frame where you have to push a pin into a hole to release the frame insert where you place the micro SD card into to place the entire frame back into the slot for the player to read the card. I actually prefer this way of inserting memory cards vs the more simpler push in card slot. Push in card slots can break after prolonged use. Unless you're not paying attention to how you insert your cards. No way of messing that up on these types of frame slots.

Sound.
Ok so this is the section where I will get into the real reason why you should take interest in this player. Fiio, has outdone themselves. The one aspect of Fiio design philosophy that you, the consumers of all things Fiio should know. Fiio does not release side grades from prior offerings. I have never once heard a newer update on a Fiio product that was not an upgrade from the former design the new item was based on. Ever. Their newer audio goods clearly shows what the group is about. Fiio employs a lot of folks over a 100 from what I read. That just means they employ a huge amount of sound/ electrical/ design engineers in a very large facility and without even going to one of their group meetings I can already tell what their business model is. That is to one up the competition and more importantly themselves. Fiio learns and keeps notes of what is critical, what works and what doesn’t for their future designs. Reads every review good or bad and take comments on the threads very seriously. It is pretty obvious to me. Since I have been reviewing audio goods from Fiio for the past 4 years with ownership of their very first DAP the X3 and their first ever Android DAP the X5iii onwards, I can clearly see with each newer audio goods just how much of a step up this “new” item is vs what they developed in the past. Case in point the subject of this read. The M15S is a step up for Fiio beyond the hardware which gets them their goal of achieving an upgrade for sound quality.

They have to give the consumer a reason to spend that cash for their shiny new player. The M15S has more power than your DAP with 5 gain settings, it has more functionality than your DAP, roon, android google play and 2 way bluetooth ready, DAC mode, Desktop mode, Line out in both 3.5mm and balanced. It comes with a fancy leather case your DAP does not provide. But the sound? It plays a big role in what's going on with the new M15S.

The sound of the former M15 is as familiar to me like the back of my hands as it was used the most out of all my sources. It was the one consistent source I used for the past 3 years and still use today. I love the old M15 for several reasons, the main aspect is that it was true to the source material it would play. It was neutral if not a touch analytical, a bit dry in its presentation in how it portrayed sound but accurate with good dynamics, clean and balanced sounding at the same time. Which was exactly the tool I was looking for to evaluate my IEMs. The aspects I wanted as an improvement from it was a better tonal character, its dynamics was good but not fantastic. Better dynamics with better texture for its sound performance, a more musical take on the neutral sound tuning is what I wanted. Getting some extra power never hurts a portable player to be truly versatile in use either.

And this is exactly what is happening on the new M15S. I remember the very first time I threw on one of my reviewed IEMs I was testing at the time, the day I got the M15S. The smile on my face was immediate as I knew right away it was an upgrade in sound. The sound of the M15S still leans neutral and balanced in delivery but this time the sound had a new sophistication I can recognize from being an owner of Fiios top desktop source the K9 Pro ESS. How much I wanted a similar sound experience on the go and to my surprise, I am getting that from the M15S. I will say the K9 Pro ESS is still my bench mark for sheer sound quality but we are talking about a desktop unit vs the portable powerhouse in the M15S. Knowing that the M15S was using the ES9038pro, the same DAC chips that are on the K9 Pro ESS. I had some high expectations of its sound performance and it met them easily from the first time I hit play.

Fiio did an outstanding job squeezing out the best performance they could using the ES9038PRO on a portable format. Despite what you read about the dreaded “Sabre glare” some of their older DACs come to mind, ES9018K2M for example. You're not going to hear yesteryear's Sabre DAC, let me put it that way. As they say in the industry, it is all about the implementation.

What's interesting about the old M15 vs the new M15S is that the older M15 used two AKM4499EQx2 and the new M15S uses a single ES9038Pro. If you went by the whole Sabre glare reputation of Sabre DAC chips and the Velvet sound of the AKM chips you would figure it would be the new M15S that is the more analytical sounding source. NOPE. That would be the older M15. Its accurate neutral depiction of sound is not the most musical or even all that velvety as the DAC chip makers would have you think. Well at least the old M15 wasn’t. It's not the smoothest, warmest sounding source, I give that honor to Shanling products and their house sound approach. Its neutrality was both a blessing and a fault.

To me, real music is not actually neutral. When have you ever heard a live concert and everything was “neutral?” On the other hand a source cannot have too much coloration in what it does either as that will skew everything you're listening to. To me accuracy was more important than coloration hence the use of the old M15. The new M15S presentation is still very much balanced in every aspect of the word but now it has an added tonal quality I appreciate about the M15S the old M15 did not actually have. The new M15S has a richer tonal quality, a better textured sound, the dynamics of your music sounds more vivid, a blacker background is absolutely crucial to hear the best details from your music and I am getting that with the M15S. This is the area I can clearly pick off as an upgrade from the M15. Not only is the new M15S supremely IEM friendly but it is headphone friendly, easily driving CANs up to 350 Ohms with plenty of head room.

Driving Fiios newest FT3 headphones yields some very surprising results. I have been using the FT3 on my K9 pro ESS and you figure it would be a downgrade in performance from using it as such to the M15S. Not really. Superb dynamics in the form of punchy defined bass, a spacious sound presentation, a denser meatier presentation with a richer sound that is just as capable but this time I can take the source and headphones with me to my backyard.

Its sound presentation is a pleasant departure for the overly neutral analytical presentations of Fiios past DAPs. It was immediately evident that I was dealing with an upgraded sound quality from the onset. After using the M15S for the past month it has clearly shown me what the real upgrade here was from the M15, and that was in its sound quality where it truly mattered. The sound stage of the M15S is impressively wide, a touch more spaced out even over the M15 and now seems to have a slightly taller and deeper sound presentation/ with a better density of sound as well. It is how Fiio manipulated the sound within that stage that has impressed me the most.

M15S treble presentation is clean in the truest sense and is superbly defined but is not as forward sounding as the old M15. How is that an upgrade? The old M15 can sound slightly brighter in tonal character using neutral monitors. This clearly showed me that its trebles were enhanced or slightly elevated in presence over its mids and bass presence. Trebles now has a more rounded even note with a heavier attack that brings a rounder, more substantial picture of the trebles when you listen critically. A more accurate timbre character to the trebles as a result. It is no secret that trebles from your sources can dictate the difference between a standard good sounding source to an articulate high end sounding source. Trebles sound more mature, more lounge if you will in characteristics. That richer tonal character carries to the treble presentation of the M15S and seems to have more contrasting sound characteristics vs the prior M15. Treble notes have a slightly darker colored edge to the sound giving the M15S treble presentation more weight and body for its treble presentation.

To be clear the sound and the differences I hear are subtle between the players but one that defines how they perform and sound. Based on what monitor you connect to these players will have a clear effect on its overall sound but these observations are more based on uniformity of the performance of the M15S.

The treble aspects you have to listen intently to pick off the differences but the differences are there. The mids however have more differences in how it is portrayed. I already mentioned Fiios prior sound characteristics are more neutral and definitely more dry in its presentation. The M15S leaves that dryness out of the M15S wheel house, now we are dealing with a richer even encroaching on a lush sound. This is where the real differences are perceived for me. Mids now have that richer tonal quality, resulting in a better contrast for its sound, in a way, the new screen being more vivid, more colorful and more dense looking vs the old screen is a very good analogy and insight into the actual sound upgrade you should expect from the new M15S vs the old M15.

I suppose you can say a slightly darker tonal character was achieved which leads to that rich tonal character but I don't know about you but I rather have rich vs dry any day of the week. It's not overly colored here but yes the tonal coloration of the M15S brings a more mature upgraded sound aspect to the M15S that I sorely missed from the M15 sound presentation. When folks say this or that has a higher end sound quality. This is what I am talking about. The technicalities for the players sound is what you would expect out of a 1K level player. It's got a supreme black background. This by the way with every new source Fiio makes has improved year in and year out. The pitch black background has improved from the old M15 in my testing. Which brings that superior dynamic contrast to the sound on the new M15S. As good as the older M15 player was, it is much improved on the M15S. Mids instrument and vocal timbre character sounds more fleshed out and realistic vs the prior M15 as a result. Imaging is superb on the player no matter what headphone or IEM you're using on the M15S.

Body of note is something real and substantial when we are talking about a higher end sound. Musical notes in how you're hearing them have to have a certain level of texture and these are the very fine details when you're listening to your favorite tracks that the M15S also seems to do better and more effortlessly. For a portable player to have these qualities, there is no question the sound quality is some of the best I have heard on a portable player at this price level.

My frame of reference comes from how this player sounds vs my older IBasso DX300Max. Which cost more than double the price of the M15S but I have to be honest and say the M15S here is easily just as dynamic sounding as the 300Max. Max might have a slight edge in stage presence but I feel the M15S makes up for it with a more tactile, denser and textured sound vs the DX300Max. They have different sound qualities but I would put the SQ level at an equal footing and that is saying something about a player that doesn't even cost half the price of that player. Then there is the bass end.

Bass of the M15S is simply more dynamic sounding vs the older M15. Actually even more so compared to most audio players sound presentations. Slightly more punchier and has some excellent deep reaching authority when portraying sub bass notes. Bass end imaging is just as engaging and defined as the mids and trebles. I don’t necessarily feel the bass notes are more elevated here but the bass end certainly feels more tactile. It's that richer sound coming through on the M15S that has yet another effect on the bass end. You figure it would be the AKM4499 integration that would present a more authoritative bass. Amplification chips make a difference for bass authority and the amplification used on the M15S seems to be leaning more toward the bass end of the sound spectrum in its sound characteristics vs the treble end. A more musical M15S?

Bass comes effortlessly in presence and can sound as delicate or as punchy as the sound engineers mixes the bass in your favorite tracks. If you're not the type to pick off real differences between sources and how they present music to your ears. If you can’t tell the difference between a dry tonal character vs a richer one, it will be the bass end you will notice just how dynamic the bass end will sound from the M15S. This is how bass is supposed to sound. It's certainly more accurate than beefy or elevated for the sake of just having more quantity but the punchy tight low rumbly bass here is a clear example of the upgraded dynamics that is a part of a richer tonal character of M15S sound.

Bass performance coming from a source has to sound like real bass. I have attended enough performances in my lifetime to know what real bass sounds like in person. A rich tonal character not only affects the treble and mids but also the bass note. Bass end has to have some gumption, some moxie and authority. Power and punch when called upon and delicate and tactile when not. If the bass end is soft or too neutral, it is simple, it won't get much play from me. Music is not music without an accurate detailed bass note and its emphasis associated with that note. This is where I feel the M15S does better in that regard and is a clear example how good bass can sound from a portable source. Bass sounds superb on the M15S and is yet another reason to love its sound presentation. You're a bass fan and want some extra bass from your M15S quality bass presentation. Get your bassy IEM pairings going on and you will love how this combination sounds.

Gain settings.
Messing around with the 5 gain settings on the M15S yields varying degrees of power and the noise floor associated with that gain. Ultra power in desktop mode for higher impedance Cans like Fiios own FT3 sound just as good as my dedicated desktops. But then on lower gain levels the noise floor is so low, my most sensitive IEMs pairings show no appreciable hiss. Tested with Yanyin moonlight and CA Andromeda. Higher gains will start to show a bit of a waterfall, a low level of noise but that is to be expected. But once you turn down that gain it is as pitch black as you would expect for a modern day player to have. This shows true versatility in form, function and its power levels.

DSD mode.
So this mode is selectable in setting options or drop down menu on the player itself. This was also an option on the old M15 but one that never really got used much as I didn’t hear a drastic benefit from it. On the new M15S however, it does provide a smoother, more analogue, slightly more organic, larger sound profile to all the tracks you're listening to. Don't know exactly what the process is to turn all your files to DSD but this does seem to give a different take on the sound vs the standard mode. My write up is all about the standard mode and what to expect but DSD mode was a bit of a surprise to me as it does seem to affect the sound and it will depend on if you want the absolute best sonics available at the cost of some battery life or its standard SQ which is excellent in the first place. And this is the only real negative in using DSD mode; it does drain the battery at about 45 minutes to an hour less.

In the end.
This is one of my longer reviews I have written, and I could have gone on even more, but I feel I have conveyed what I wanted to for my readers. To me it is simple. Unless you absolutely must own the fastest SOC and the latest OS on your Digital Audio Player. The new Fiio M15S is your one stop source for all things music. If sound quality and its versatility with good power is what you care about for your music player. The M15S needs some serious consideration. Its price to performance ratio is outstanding. Its sound presentation is not just good my friends, it sounds stunning. That is a sound descriptor I honestly can’t say about their former M15 as much as I loved using it.

At the time I thought it was clearly worth the $1300 I paid for to own and believe me; I got my money's worth in usability and enjoyment out of that player. The New M15S is $1000 and is a clear upgrade on that player, it's not a sidegrade at all as some reviews might tell you. Take it from someone that has been using that player just about every day since it came out. Fiio has read my mind and has come through huge on all fronts for this player. If you're looking for a player you will get real value with. That player, my friends, is the one you have been reading about. Thanks for taking the time to read, happy listening always.