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The FiiO M3K - probably as much DAP as you really need

AnalogSteph

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It seems to me that this little player could use a dedicated thread here. @Robin L seems to be one of the few dedicated fans.

With my fleet of Rockboxed Sandisk Sansa Clip+ starting to show their age, I was looking for a replacement, preferably an improved one. Aside from input being partially touch, the FiiO M3K was ticking all the boxes. Rockbox compatibility, MicroSD storage (up to 2 TB), neither microscopic nor a huge brick (anything that does not fit a shirt pocket is automatically out), good battery life, a decent display (2" color IPS, 240x320, with pre-installed glass protector no less), AK4376A DAC / headphone driver with well-documented performance, not breaking the bank (69€ at writing), and if you boot OF you have USB DAC functionality (needs drivers though) and voice recording as well. The Ingenic SoC has 32 MiB worth of RAM built-in, and a MIPS core clocking up to 1 GHz should provide enough oomph to make up for any potential lack of optimized inline assembler code. The outside of the player is protected by a silly cone silicone case right from the factory.

Installing the Rockbox bootloader according to instructions provided is a bit fussy but doable. Tools required on Windows are much the same as what's required for rooting/debranding an Android phone, I think. My new MicroSD card (Samsung MicroSDXC PRO Plus 256 GB, no expense spared) was reformatted to FAT32 using the HP USB Disk Storage Format Tool and an external cardreader.
Theme wise, I settled on Googley-FuzePlus-Clippy, and used the convttf utility now provided among existing font downloads to make a version of the GNU Unifont in a size I can actually read (24 with -c 2). Not the prettiest font (the numerals rather suck) but without CJK support I am SOL. This is an ongoing battle.

Performance stats collected so far:
* 0 dBFS (0.9999 FS) output amplitude at volume setting 0 dB: 0.906 Vrms (according to my UT71C TrueRMS multimeter), matching chip spec of 0.57 Vrms at -4 dBFS if you do the math
* Maximum undistorted 0 dBFS output reached at volume setting +2.5 dB, that's pretty much exactly 1.2 Vrms (a.k.a. iPod standard)
* Battery life seems approx. 20 hours with my mix of Amazon MP3 and MP3 LAME -V 4 (way better than a Clip+ with an aging and never very good battery for sure, with a MicroSD card installed that never gave me more than about 10 hours)
* SD throughput via USB: OF 18 MB/s read & 7 MB/s write, Rockbox 12 MB/s read and 6.5 MB/s write. Use a USB3 cardreader for bulk transfers (said Samsung card can write at least 90 MB/s sequentially and will appreciate UHS2 support).

No appreciable noise when using a KZ ZSX IEM of ca. 118 dB / V sensitivity (in line with device spec of <2 µV), just a bit of a click on power-off. The output is DC-coupled and ground-referenced as expected from the AK4376A. USB DAC functionality takes a good while to unmute after playback starts. Rockbox will support sample rates up to 192 kHz with autoswitching but documentation is warning about potential unresponsiveness at 176.4k/192k.

The tactile power / volume / play buttons on the side are good, the capacitive touchpad takes a bit getting used to but is not too bad per se. Taking some time to configure button locking is no doubt worth it. (I turned on autolock, autolock always, and exceptions for the side buttons. Sort of wishing that volume and skip buttons could be swapped, but it's OK as-is. I'd have to compile a RB build myself with a custom key mapping, something I last did 10+ years ago.)

I have yet to measurably verify audio performance but given RMAA results I am fairly confident that it is about as good as they specify (SNR ≥117dB(A-weighted), THD + N <0.004%(1kHz/32Ω), Output impedance<1Ω(32Ω load)). A nice step up from the Clip+ which had been pretty much exactly at 16 bit level DAC wise (95 dB(A) worth of dynamic range on a good day, 1 kHz distortion ~0.0025% when bypassing the mixer, and negligible filter ripple). Perhaps more importantly, the Clip+ also had some audible analog hiss and low-level noises with IEMs - and that had been among the better players in its day. (You can still buy noisier players right now.)

Subjectively, the ZSX sounds a bit smoother on the M3K compared to the Clip+ (maybe due to lower ground return resistance and/or output impedance?), and I slightly tweaked the EQ as follows:
Code:
eq enabled: on
eq precut: 45
eq low shelf filter: 710, 7, 45
eq peak filter 1: 64, 10, 0
eq peak filter 2: 125, 10, 0
eq peak filter 3: 250, 10, 0
eq peak filter 4: 500, 10, 0
eq peak filter 5: 750, 5, 30
eq peak filter 6: 2000, 10, 0
eq peak filter 7: 6000, 5, 0
eq peak filter 8: 8000, 10, 0
eq high shelf filter: 3000, 10, -15
There is some bias due to primarily mobile use, perhaps some loudness as well. This IEM supposedly follows Crinacle's target curve fairly well, I can't say it sounded balanced to me barefoot. Great SQ for the price with a bit of EQ though.

Maximum output has rarely been a problem for me as I tend to be a fairly quiet listener (perhaps 10 dB below average). I was able to just about max out a Clip+ (800 mV max) with HD580s on notoriously dynamic Mahler symphonies, with peaks in the low 90s dB SPL. On the M3K I have set HD580 config default volume at -31 dB, limit at -7 dB. So if you have nothing more demanding than the usual 250/300 ohm Beyerheisers or ATH-R70x' (102-103 dB / V) and normal hearing, I predict the M3K will do just fine. The 50+ semi-deaf club with demanding planars need not apply or should use an amp. This is a normie player for normal headphones, not outrageous excess. Being able to hit 25 mW @ 32 ohms (that's pretty much exactly 0 dBFS at 0 dB, and = chip spec) is respectable enough.

It seems quite fitting to be using a Clip-themed Fuze+ skin on the M3K, as it is sort of a Fuze+ on steroids and replacing a Clip+. Build quality seems rather better though, both my current Clip+' have more or less annoying bugs that I attribute to soldering issues (one has never charged to 100%, the other has an RTC that's running annoyingly fast). Having a full color screen of a decent resolution is obviously a revolution, too (I could fit about 3 lines worth of text on the Clip+), even if the pixel pitch makes a size 8 font unreadable entirely. The backlight is a tad on the bluish side unfortunately and makes one wish for color management facilities, but that's not unusual on inexpensive displays. On the upside, I rarely need to crank up the brightness beyond 50%, and touchpad lighting is plenty adequate at 6%. The display backlight appears to be flicker-free.

Of course it figures that a player that ticks all the boxes apparently is no longer in production. If it's just AKM's outage that was the issue, FiiO could respin the player with the newer AK4377A fairly easily, which has been listed as being back in production for a while now. It seems the designated successor would be the M3 Pro based on an ES9218P and with a full-front touchscreen that came out in 2020 - I don't doubt it's a good player, just no Rockbox port (yet). It seems feasible enough, the biggest obvious hurdles being the DAC (I found a full datasheet at least) and the display.

In any case enough M3Ks seems to be out in the wild for them to remain readily available - at least for now. Once I had verified that it would be fit for purpose, I bought a second one. Better safe than sorry in this day and age.
 
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maverickronin

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How well does Rockbox run on it?

I got an xDuoo X3 II a few months back and it's Rockbox port is pretty buggy.
 
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AnalogSteph

AnalogSteph

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How well does Rockbox run on it?
Pretty much as well as the wiki suggests:
At present, it should be stable for audio playback and general everyday use
The biggest issues I've had was related to font sizes, there are a few screens like graphical EQ or on-screen keyboard that aren't using the default font which come out very small, and some debug screens are hardcoded to a downright microscopic size 8 font.

Using a build from the 24th of December, I have seen very little in terms of glitches and crashes so far. With a collection the size of mine, it is very much advised to do a database init with playback stopped and leave the player alone during this time, but that was no different on the Clips. (Also, I haven't tried updating the database again, but that would previously take ages, to the point where I decided to just do another init when needed.)

I used to run a build from early 2018 on my Clip+ for years, assuming that little would have changed - well, after updating the build not long ago it turns out one of my long-standing gripes had been fixed in the meantime, namely the player becoming terribly sluggish during track change when scrobbling was turned on. Now it scrobbles like a champ, and so obviously does the M3K.

I got an xDuoo X3 II a few months back and it's Rockbox port is pretty buggy.
Huh. What sort of problems are you experiencing? The wiki says
The stock firmware (and Rockbox) runs as an application under an Android Linux kernel.
[...]
Rockbox functions well on this, and nightly builds are considered stable for day-to-day use.
The bug tracker notes only a handful of issues, the most major annoyance arguably being FS#13252.

Since this is not a native build (unlike the M3K), I wouldn't expect anything too terribly terrible to be happening. I wouldn't discount a potential hardware issue. The biggest variable here arguably is the choice of MicroSD card.
 

charleski

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SD throughput via USB: OF 18 MB/s read & 7 MB/s write, Rockbox 12 MB/s read and 6.5 MB/s write.
This is the real pain in using a system based on SD cards. It’s not helped by Rockbox being limited to FAT32, but these interfaces seldom come near to the speed the card can really handle. In my experience it can take 12hrs or more to fill up a 256GB card.
 

maverickronin

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This is the real pain in using a system based on SD cards. It’s not helped by Rockbox being limited to FAT32, but these interfaces seldom come near to the speed the card can really handle. In my experience it can take 12hrs or more to fill up a 256GB card.

Just pop it into an external reader and it will go as fast as the card.

The biggest issues I've had was related to font sizes, there are a few screens like graphical EQ or on-screen keyboard that aren't using the default font which come out very small, and some debug screens are hardcoded to a downright microscopic size 8 font.

Using a build from the 24th of December, I have seen very little in terms of glitches and crashes so far. With a collection the size of mine, it is very much advised to do a database init with playback stopped and leave the player alone during this time, but that was no different on the Clips. (Also, I haven't tried updating the database again, but that would previously take ages, to the point where I decided to just do another init when needed.)

That's encouraging.

I used to run a build from early 2018 on my Clip+ for years, assuming that little would have changed - well, after updating the build not long ago it turns out one of my long-standing gripes had been fixed in the meantime, namely the player becoming terribly sluggish during track change when scrobbling was turned on. Now it scrobbles like a champ, and so obviously does the M3K.

If the modified date of the bin file is correct my Clip Zip is running a build from 2012 and has been rock solid as my constant podcast and audiobook player.

Huh. What sort of problems are you experiencing? The wiki says

That's what it says...but it's not all that great. The most annoying problem is that scrolling through lists, file or database, is comically slow. By the time I get the bottom of the screen it slows to pace of 1 line per several seconds. I mostly get around it using the A to Z option in the database. Attempting to play particular files will crash the entire player as well.

The stops playing while scrolling thing is kinda trivial in comparison.
 
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AnalogSteph

AnalogSteph

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Just pop it into an external reader and it will go as fast as the card.
More or less. Using a Kingston FCR-HS3 I saw like 35-38 MB/s when filling this card with -V4 MP3s, up to 40-50 on slightly higher bitrate material. And that's only the third fastest cardreader I tried, at 65 MB/s reading and 59.7 MB/s writing according to h2testw. A Lexar RW500 rev. B that I got for curiosity's sake reaches 121 MB/s reading and 95.3 MB/s writing. (Nonstop reading results in a very hot little MicroSD card very fast at these speeds.)

Speaking of MicroSD cards, the slot on the M3K ends up being relatively far recessed. You better have some semblance of fingernails to pop them in and out. Not an issue for me but worth mentioning.
If the modified date of the bin file is correct my Clip Zip is running a build from 2012 and has been rock solid as my constant podcast and audiobook player.
You are potentially giving up a lot of battery life like that, as considerable power management improvements (CPU and SD) were made just a few years back. A current build will also support sample rate autoswitching (and you can select up to 96 kHz, I never knew the DAC could do that). There were some improvements to the bootloader as well, including being able to boot from MicroSD (which may become a necessity should the internal memory ever decide that it's had enough and go read-only, which has happened). As always, back up .rockbox and be prepared for a bit of a fight with themes.
That's what it says...but it's not all that great. The most annoying problem is that scrolling through lists, file or database, is comically slow. By the time I get the bottom of the screen it slows to pace of 1 line per several seconds. I mostly get around it using the A to Z option in the database.
Yikes. They said the LCD driver was kinda slow, but that's bad. The M3K is definitely zippy, no complaints there.

Speaking of displays, I remember seeing a note about a change in display block writing in some build not that long ago. Trying a current one is worth a shot at least.
Attempting to play particular files will crash the entire player as well.
Is it always the same files? If so, inspect their tagging, album art in particular (RB can be a bit unforgiving there), alongside the usual like format and sample rate.
 
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maverickronin

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You are potentially giving up a lot of battery life like that, as considerable power management improvements (CPU and SD) were made just a few years back. A current build will also support sample rate autoswitching (and you can select up to 96 kHz, I never knew the DAC could do that). There were some improvements to the bootloader as well, including being able to boot from MicroSD. As always, back up .rockbox and be prepared for a bit of a fight with themes.

Battery life is still good enough for my use despite being so old and heavily used and I don't really want to take a chance on breaking anything, or just having to fight with the themes again.

Yikes. They said the LCD driver was kinda slow, but that's bad. The M3K is definitely zippy, no complaints there.

It's not even the hardware, just the Rockbox port. The OF is plenty fast - just missing essential features, like basically everything else besides Rockbox.

Is it always the same files? If so, inspect their tagging, album art in particular (RB can be a bit unforgiving there), alongside the usual like format and sample rate.

I think it is, but I haven't really investigated it much.
 

Robin L

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Here's mine, got it two years ago. I've got a 512GB Micro-SD card in it, mostly Apple lossless files. It's got something like 1500 CDs worth of material, including a lot of historical Folkie music from a DVD full of Redbook files otherwise difficult to access. You see it here to the left of the a/d/s/400e speaker and amp it's hooked up to at the bottom of the picture. The Drop 6XX headphones usually aren't attached to the M3K, they work better with USB/Topping E/L30 combo, on account of the bass boost I get from the PEQ on the laptop that's passing along tunes to the Topping pair. But over speakers, or when I use the AKG 371 'phones, I really can't hear enough difference to get excited. It's a wonderful way to play very long playlists without interruption or attachment to a computer, a cheapskate music server:
IMG_20210617_085714142.jpg
 

charleski

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Just pop it into an external reader and it will go as fast as the card.
Fine if you already have one, such as for photography. But a truly fast usb-c card reader that can handle the card’s full read/write rate will cost at least a third the price of the Fiio. The Lexar AnalogSteph mentioned goes for $22. If you’re a Starving Student working on a tight budget this may be a significant extra expense for something that will be used infrequently.
 
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AnalogSteph

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A literal Starving Student may have difficulty filling up a large memory card in the first place though... torrenting isn't as popular as it used to be for one thing. Besides, a cardreader tends to last you a good long while if you get a good one to begin with. The Kingston FCR-HS3 I mentioned may well be dating back to the time Dad got his DSLR in ~2012, and while outdated by modern standards, it still is decently fast now. The Lexar (which cost me less than one memory card) can reportedly hit 300 MB/s with UHS-II cards, and I don't see SD, MicroSD and CF going away any time soon.
 

charleski

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A literal Starving Student may have difficulty filling up a large memory card in the first place though... torrenting isn't as popular as it used to be for one thing. Besides, a cardreader tends to last you a good long while if you get a good one to begin with. The Kingston FCR-HS3 I mentioned may well be dating back to the time Dad got his DSLR in ~2012, and while outdated by modern standards, it still is decently fast now. The Lexar (which cost me less than one memory card) can reportedly hit 300 MB/s with UHS-II cards, and I don't see SD, MicroSD and CF going away any time soon.
None of this changes the fact that a player that looks like a nice budget buy at $70 actually needs an outlay of close to $100 to be usable, an extra cost that will only become apparent after trying to write to the card using its glacial controller. Unfortunately most such devices cheap out on the SD interface, so the Fiio isn't alone in this.
 

karthik7000

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I am a student. I have not much budget for this one but I really like Fiio m3k. The processor like X1000E processor is very nice.
But i hard to find it in india.
 
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AnalogSteph

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None of this changes the fact that a player that looks like a nice budget buy at $70 actually needs an outlay of close to $100 to be usable, an extra cost that will only become apparent after trying to write to the card using its glacial controller.
If you're buying a player that hardly hides the fact that it requires a MicroSD card for storage, you kind of know what you're in for. So the card itself is kind of a given, and its size (and ultimately, price tag) is going to depend on your collection, which in turn has likely consumed thousands or at least hundreds previously. Over about a decade of Clip+ use, my memory cards have grown from 8 GB over 16 GB (I wonder if whoever ended up with our old '91 Honda Accord ever found the one that went flying in the back seat and was never seen again), 32 GB, 64 GB to 128 GB, and those were getting a bit full lately. Being able to use a memory card was an absolute godsend, I never would have gotten very far with the built-in 8 gigs and progress meant that available card capacities kept growing. The 256 gigger cost me a whopping 40€ now.
A total of 110€ for both player + card sure beats the 400+ for a 256 gig iPod Touch (with non-upgradeable internal memory only) or other, even more expensive options.

That leaves the cardreader itself. Even if your time is not worth $30 for a new one, those are not exactly what you would call a rarity in this world. A laptop from about the last decade is likely to have a serviceable one. I think I have 5 for USB now, down to one for USB 1.1 that I kept since it worked the best with the xD-Picture Cards for my old Olympus SP-310.

Having almost the same SD interface speed in a 2018 product as in 2010 is a bit lame, that's true. Power consumption concerns might be outweighing speed demands here. Besides, DAPs can be a bit stuck in the past anyway - Cowon still uses SoCs from 2010 and dead-end Flash animation from the 2000s on brand new players (if combined with CS43131s). That's not what I meant by an existing code base being a good thing... I'll gladly live without mid-2000s style gimmicky "sound enhancements", thank you very much.
 

MRC01

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It seems to me that this little player could use a dedicated thread here. @Robin L seems to be one of the few dedicated fans.
...
What benefits do these portable players provide, beyond using a phone with a good player app? For example, in REW my phone measures near perfectly flat response and vanishingly low distortion through its headphone jack, and with USB Audio Player Pro, provides bit-perfect playback into an external DAC, and with ToneBusters it has built in DSP including EQ and headphone crossfeed. The only downside to my phone is that its headphone jack output is too weak to properly drive my full size headphones.

Is it that these portable players have a more powerful analog output / headphone amp, or is there more to it?
 

Robin L

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What benefits do these portable players provide, beyond using a phone with a good player app? For example, in REW my phone measures near perfectly flat response and vanishingly low distortion through its headphone jack, and with USB Audio Player Pro, provides bit-perfect playback into an external DAC, and with ToneBusters it has built in DSP including EQ and headphone crossfeed. The only downside to my phone is that its headphone jack output is too weak to properly drive my full size headphones.

Is it that these portable players have a more powerful analog output / headphone amp, or is there more to it?
It's that it's not a smartphone, thus freeing up the smartphone to be a smartphone. ;)

Also: tiny. 1/4 the size of my smartphone.

The volume output of my M3K is much greater than the volume of my Moto, if that's any help. The Fiio player has more than enough power for my AKG 371 headphones, not quite enough for the Drop 6XX, though the combo sounds pleasant enough for music that doesn't emphasize the two bottom octaves. With the AKG 371 one can play back just about anything with full volume and plenty of impact.
 
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maverickronin

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What benefits do these portable players provide, beyond using a phone with a good player app? For example, in REW my phone measures near perfectly flat response and vanishingly low distortion through its headphone jack, and with USB Audio Player Pro, provides bit-perfect playback into an external DAC, and with ToneBusters it has built in DSP including EQ and headphone crossfeed. The only downside to my phone is that its headphone jack output is too weak to properly drive my full size headphones.

Is it that these portable players have a more powerful analog output / headphone amp, or is there more to it?

For me the the biggest advantage is that you can still get DAPs with a full set of face buttons.
 

Joaquin Dinero

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A lot of hand wringing about SD cards here ? Every laptop I've ever owned has an SD drive built in. I can load up a 256GB card in a few hours, pop it into the device, rescan library, and you're ready to rock. I find it to be exceptionally convenient.
 

Nango

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Painful navigation through the content, only scrolling allowed, if you want to play ZZ Top expect decent amount of time until you get to the "Z" by scrolling thru all the artists (i.e.no jump possible from A to Z). Painful, don't recommend unless your artist or album starts with an "A" ........
 
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