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Global feedback: the battle for gapless playback, vol. 2

  • Fabric. Earlier this month, the iconic London club was forced to close by Islington Council in the wake of two drug-related deaths. Maintaining the club’s legacy is an close-to-peerless series of compilations that offer the finest dance/electronic music of the moment, mixed by some of the world’s best DJs.

    At time of writing, we’re up to volume 89 in each of the Fabric and FabricLive series. That’s 178 DJ mix albums since 2001, all from a single label. Further afield, there exists hundreds of other record labels doing much the same.

    For fans of electronic music, especially throughout the 90s and 00s, the mix CD was a way to get a taste of the DJ’s selections and mixing skills without attending an event. Others use the DJ mix as a way to carry the weekend’s party vibes into the working week.

    Skilfully mixed, the best mix CDs deliver more than the sum of their parts: Jimmy Van M’s Bedrock mix, James Holden’s At The Controls, 2ManyDJs’ As Heard On Radio Soulwax Vol. 2, Sasha & Digweed’s Northern Exposure Vol 1. (and 2!), Joris Voorn’s Balance and Function’s Sandwell District Fabric mix all rate highly.


    Irrespective of any intrinsic artistic value, the DJ mix is rendered unlistenable without the presence of gapless playback. Even the tiniest audible gap between tracks disturbs what is meant to be continuous mix; its flow is compromised.

    In the CD era, this wasn’t an issue. CDs are pressed as one track with the track segmentation applied virtually by the disc’s table of contents, as read by the CD player. But as owners have ripped those CDs to hard drives or purchased as a download, tracks arrive as separate entities.

    For proper gapless playback of digital files, the music playback software must read ahead and buffer the incoming track before the currently playing track comes to a close. This often requires two CPU threads: one to handle playback now and the other to pre-fetch file data that will soon require playback. (My technical understanding of the nuts and bolts of gapless playback extends no further than this).

    Nowadays, it’s not only locally stored files that require gapless handling. Streaming services are now very much part of the audiophile lexicon, especially Qobuz’s, Tidal’s and Deezer’s lossless tiers.

    Users might grumble that the Sonos ecosystem doesn’t yet support Spotify Connect (that changes soon) but the Santa Barbara-based company have ensured that gapless playback is present and correct for Tidal and Spotify (and other services) as well as all LAN-streamed content.

    Tidal’s desktop and smart device apps each play gaplessly but the Tidal playback engines coded into the Google Chromecast Audio, OPPO BDP-105 and Devialet Phantom/Dialog do not. It’s why I chose to connect an AURALiC Aries Mini to the Dialog’s single TOSLINK port – Lightning DS puts gaplessness back on the map, all of which might not be apparent to the casual observer who must get hands on him/herself to find out the hard way* [see footnote 1].

    It’s been three years since I last tackled this issue – catch up here. My beef back then wasn’t necessarily gapless playback’s absence but that many a hardware manufacturer shied away from declaring it. And if they did, we were encouraged not to sweat it – a firmware fix was apparently ‘just around the corner’.

    How long that wait was unknown – a reminder to never buy on the back of a promise. As many a PS Audio Bridge owner will recall. In 2011, Paul McGowan spent a good deal of time and money trying to erase the gaps heard from the first generation Bridge. He eventually threw in the towel and built more powerful hardware; the Bridge II offers no such intra-song limitations.


    Like many hardware companies, not all software houses see gapless playback as a nice to have extra. “It’s critical”, said Roon CEO Enno Vandermeer upon learning that his playback engine was splicing tiny gaps between each track on Marcel Dettmann’s Fabric mix when played on my Macbook Air. The ensuing Roon update fixed the issue pronto.

    The absence of gapless playback can really strip the shine from a new DAP or network streamer purchase. I now ask about a device’s gapless abilities BEFORE picking up a review assignment, just as a consumer might before dropping big coin.

    At CanJam SoCal in March, a pre-production HiFiMAN SuperMini caught me off guard. Its lack of audible treble glare (that I hear from the Sony NW-ZX2) primed me for a review when the time came. Before requesting a sample unit in the wake of HiFiMAN’s recent shipping announcement, I hit up the Chinese manufacturer via its Facebook page: “Does it [the SuperMini] do gapless?”. “YES!” came the resolute reply. Good-oh. Hit me.


    With the review unit’s arrival came trouble. My first impressions about its more organic sound were confirmed but the firmware saw the SuperMini ask if I wanted to format the microSD card (it reads FAT32 only) each and every time I inserted it anew. “It’s a bug with the current firmware. We will fix it with the next firmware update,” said HiFiMAN’s Riccardo Yeh.

    What couldn’t and wouldn’t be fixed apparently was the unit’s absence of gapless playback.

    “How do I enable gapless playback? Right now each song fades out quickly at the end before the next one fades in quickly when it starts – no good for DJ mixes,” I asked.

    On a related note, the SuperMini’s track start ramp-up robs any track announcing itself with a thwack of its initial attack. Think: Bob Dylan’s “Like A Rolling Stone”.

    Yeh’s reply retrospectively announced an 11th hour change: “They close the gapless function to make sure the CPU can work under single threaded mode and avoid the jitter as much as possible. Dr. Fang insists that this is a “must” sacrifice for superior sound quality.”

    “It’s a pity that we won’t develop the firmware featuring gapless playback for SuperMini in the future,” added Yeh 24 hours later.


    A necessary sacrifice according to HiFimainMAN Dr Fang Bian but not one this listener is prepared to make. DJ mix CDs, live albums or any album where seamless track transitions are “as the artist intended” are pushed into the background. Review cancelled, unit returned to sender.

    Dr Fang’s functional sacrifice will also affect the freshly announced, crowdfunded MegaMini.

    It isn’t just HiFiMAN. The Chinese xDuoo X3 suffers the same gap-toothed look. Thankfully, this Rockbox port removes the holes.

    CDs are gapless. Ditto vinyl records. In moving forwards with digital audio, we are sometimes being asked to accept the backwards step of its implementation. Reasonable? For this techno fan, a lack of gapless playback signifies a refusal to acknowledge the artistic intentions that sit behind an enormously popular sub-genre of music.

    However, it is important to ask: is gapless playback a minority concern? Over to you then, dear reader, for the bigger picture. Have your say in the comments below after voting in the poll:

    [poll id=”7″]

    Please let us know of any other devices that don’t offer gapless playback.

    Footnote 1: Not my intention to single out Tidal here but it’s the lossless streaming service that I (and others) use most often.

    John Darko

    Written by John Darko

    John currently lives in Berlin where creates videos and podcasts and pens written pieces for Darko.Audio. He has also contributed to 6moons, TONEAudio, AudioStream and Stereophile.

    Darko.Audio is a member of EISA.

    Follow John on YouTube or Instagram


    1. In this day and age, the expectations are for new devices to outperform the old. One need only reference the flagship smartphone market to see the endless quibbling about specs and performance. However, the fact that gapless digital music playback has been deemed, “optional,” by numerous hardware manufacturers astounds me!
      Non-gapless playback gripes for me began with my first DVD player, which would freeze the movie while the player changed reading the layers on the disc. I thought I had a faulty player or disc before I realized what was actually happening. Now, the fact that we can store thousands of hours of CD quality FLAC music on a card that is the size of a fingernail makes gapless playback of that music seem nonsensical. I am by no means a software engineer, so I don’t understand the ins and outs of making it happen. But the fact that it does happen on some devices and not others, means that there are solutions. I can understand an inexpensive $35. Google Chrome not having gapless capability. That’s a lot to ask for the price, but some that costs hundreds or thousands… It should be a given.

    2. In my view, gapped playback is the grossest form of distortion imaginable: you go from 100% of the music to 0%, even if it’s only for a moment. This is a really, really big deal in classical music. Gapped playback is completely and utterly unacceptable, and I am stunned that someone as seemingly devoted to high fidelity as Dr. Fang would even consider it.

      • I totally agree.

        Even though I’m the metal head in the room and can probably deal with it, all of my classical tracks are just a non-starter with any playback device or software that doesn’t do gapless. Like we both said, it would sound ridiculous.

    3. I suspect it is due to the low power chip the SuperMini uses. Perhaps Fang doesn’t want the prefetch to interrupt the main play thread in single threaded mode (hence his “jitter” comment).

      However, compromising playback with fade in and out is just awful. I don’t understand how Fang can possibly think fading out Mozart makes a slick a sense. I’ll take the jitter thank you.

    4. Not just techno! It’s curious that you don’t notice that an album is “gapless” until you play it on a device that doesn’t support it. Wrt gapless on the Oppo, I wonder if that may be an Oppo issue not a Tidal issue, as sending via DLNA (to my 103) also doesn’t support gapless.

      • Yes, it could be either OPPO or Tidal – I’m not assigning blame, merely stating the facts as I see ’em. But one would assume that Tidal signs off on each implementation?

        • I would imagine so, but they may not have a choice – the Oppo firmware may simply not be able to do gapless for data coming in from the network (for reasons along the lines you’ve outlined for the Hifiman). I have read that gapless playback was added to the Oppo firmware but only for files located on local storage. I’ve not tried that. At any rate, this is a bit of an aside – your article is spot on!

      • I singled techno/electronics out as I’d wager that DJ mixes are listened to by more people than any other form of music where an uninterrupted flow is fundamental to the artistic process.

        • A lot of Prog and Classical music also gets released in gapless format, and I reckon their numbers equal techno/electronica. Note that I don’t include “Dance” music (you know, the Ferry van Buurens and Steve Guettas and such) in the electronica genre any longer – even iTunes has separated the two, in fact. Funny, that.

          I miss the days of the mix CD. Phil K’s Balance mix (particular the breakbeat first disc) is another gem from that series, besting both Holden and Voorn’s efforts, imho. Fabric 01 – Craig Richards and 02 – Terry Francis are classics in their own right as well. Digweed’s Bedrock 01 was another, along with some of the very early GU releases.

          Gapless also posed a problem for CDs as well, actually. I remember some CD players not being able to do gapless, though those were mainly limited to the budget “mini-compos” I used back in highschool.

    5. Fiio´s X7 also has no gapless. Should be fixed with a future update. Yeah, sure…..
      Since I´ve switched to AK, my AK300 Dap plays everything (!) gapless.

    6. I am sticking to my idevice + mojo… seriously, it’s more than a “nice extra” it’s a necessary feature for anyone into mixes, concert recordings, concept albums and classical. the problem is most audiophile/engineers don’t listen through an entire track let alone an album.

    7. I use a Bluesound Node, which does support gapless. However I have tried other systems which don’t such as Plex & Kodi – I was experimenting with having a pretty UI to look at on my TV while I listen to music.

    8. Pioneer N-50. ‘Technically’ gapless but only if you used Pioneer’s own Control app. This would be ok if it wasn’t for the fact that this app was one of the most incompetent apps designed (Still is, I just checked the iTunes store). If you have a library of 10 albums it might be passable, but anymore than that and the amount of swiping required to find the album you wanted would drive you crazy – no search function built in.
      I heard that Pioneer decided to write their own implementation of DLNA which is why gapless doesn’t work using any other playback software. This is a pity, because I thought the N-50 sounded very good. It doesn’t just do streaming, it has usb & spif/toslink inputs too. But I’ll think very, very carefully before buying anything from Pioneer again.
      Perhaps the moral of the story is to try before you buy, but that’s not always possible for everyone.

    9. John,

      Thanks for this article. Keep “sticking it to the man” on this issue. If a device/software can’t play 1970’s “Dark Side of the Moon” as it was meant to be heard and has been heard by the countless masses then something is wrong. Just last night I was listening to Tidal through my JRiver (where I can EQ using a plug-ing) with BubbleUPnP (so that I can use my tablet as a remote) but alas, no gapless. BubbleUPnP does have some nascent gapless capability with local files, but not with Tidal. I suspect this is a software hook issue on the Tidal side (who probably does not cooperate with other vendors like BubbleUPnP) but we consumers do expect this basic functionality…

      • In BubbleUPnP, you need to enable Settings > UPnP Tweaks > Enable gapless control > , to drive JRMC (or any other renderer supporting gapless) gaplessly.
        It is disabled by default because it breaks playback advance on too many renderers.

    10. Keep up the fight for gapless playback is vital. And like everything else in the audiophile world interfering with enjoying music people are the problem. Thanks for another good data point. Finally what is your alternative for Tidal?

    11. A lot (most?) classical is gapless. Since that’s what I listen to gapless playback is essential.

      But if one were to listen to the Brothers In Arms LP the songs blend into one another. Another crucial need for gapless.

      Finally, I have a Peter Gabriel Live in Athens! recording. That should also be played gapless because otherwise there’s this jarring fade of the audience and the end, slience, then the audience fades up again.

    12. That’s too bad about sending the unit back, John. I was really looking forward to your insight concerning battery life, sound quality, and its ability to push more-demanding headphones/earphones. Reading the description of the unit, I thought these were the major selling points. I’m not saying that gapless is irrelevant, but all of the other features I’m just a bit more interested in. It looks as if sacrifices definitely were made (gapless being just one of them) to advance the overall concept of the product. I was hoping that we could compare notes, after your review was complete, as I recently purchased a SuperMini unit from HiFiMan. Oh, well. My knowledge, or resources, are certainly not as vast as yours, but I would be happy to provide you with a perspective on the unit, once I’ve used it for a bit. If you’re interested.

      • Yes please, by all means add your thoughts to this thread or the other news thread. For me though, no gapless means no deal as both customer and reviewer.

    13. Maybe you need to ask them to sand you the sample again, John. Dr. Fang Bian just gave an open letter on head-fi:

      To Friends and Customers of HIFIMAN:

      Within the past two to three days, there has been some discussion online about the HIFIMAN SuperMini and MegaMini that I feel contains misinformation about the technology we use. So in the interest of clearing up any confusion and to make everyone comfortable in their consideration of our players, I offer the following clarifications.

      HIFIMAN new player SuperMini and MegaMini: Single thread mode
      A portable music player (PMP) is actually a mobile computer. There are a lot of portable music players that use an Android or Linux operating system. These systems are in multi-thread mode: CPU executes multiple processes or threads concurrently. Multiple threads can interfere with each other when sharing hardware resources, which creates jitter when playing music.

      In computer programming, single threading is the processing of one command at a time. Instead of developing the music player software on existing Android or Linux operation system, the HIFIMAN team has developed its own embedded operating system. Specifically, HIFIMAN SuperMini and MegaMini are portable music players working in “single thread mode” most of the time; only some very small tasks such as displaying and button responses are running on multi-thread mode sometimes. More than 95% working time, they work as single threading so that their jitter level is much less than that of an Android or Linux PMP.


      About Gapless
      When a PMP is playing music as gapless, current technology has to play music and read the next track simultaneously. That way it will play the next track as soon as it finishes playing the first track. Therefore, it is a multi-threading process. However, the HIFIMAN team has figured out a way to support gapless playback in single thread processing. In other words, there is no more jitter generated when a HIFIMAN SuperMini or MegaMini player is working as gapless.

      The current beta version firmware of SuperMini and MegaMini cannot support Gapless. However, we did figure out how to do gapless playback on SuperMini and MegaMini players and still keep them working as single thread processing so that there will be no more jitter. We plan to support it in the official version firmware before the end of the year.

      Supporting Exfat SD card
      The current SuperMini and MegaMini cannot directly run an exfat format SD card however you can format it in the player and support 64, 128 and 256G SD card without any problems. We are currently working on supporting exfat and will support it in the official version firmware later this year.

      If anyone has any questions, or would like further information, please contact [email protected]. Thank you for your support.

      Best Regards,

      • That IS interesting because I asked if gapless playback would ever be added down the line and the reply from Riccardo Yeh after speaking to the engineering team was this:

        6th Sept: “I will ask our engineering department tomorrow if there will be any possibility to open the gapless function in the future.”

        7th Sept: “It’s a pity that we won’t develop the firmware featuring gapless playback for SuperMini in the future.”

        Prior to that Riccardo had quoted Dr. Fang as saying gapless was a “must sacrifice”.

        In this post I explained (in a more basic fashion) that which Dr Fang has outlined in his open letter about gapless’ need for multi-threading.

        Again on 6th Sept, here’s Riccardo: “Dear John, I just asked our engineer and got the answer: they close the gapless function to make sure the CPU can work under single threaded mode, and avoid the jitter as much as possible. Dr. Fang insists that this is a “must” sacrifice for superior sound quality. I will let our admin to delete the reply on FB. We are sorry for the misleading answer.”

        I find it a little bit “off” that Dr Fang would allude to this being misinformation when his stance prior to today’s/yesterday’s open letter was that gapless was surrendered on the SuperMini in the name of SQ – the above email quotes confirm as much.

        I also asked on Facebook about the MegaMini doing gapless and the reply was “no”. That was two days ago.

        • Not surprised. Your article here draws a lot of attention on head-fi. I think Dr. Fang Bian changed his mind after reading it and the feedback from other head-fiers. Since they can develop some way to achieve gapless under the single thread processing, it’s always a good news for users.

    14. Not quite sure if I’m fully understanding this…er…gapless business but my humble iPod Touch can play gaplessly, yes?

    15. I started the conversation about this issue over on head-fi. I´ve noticed no difference in sound quality since AK recently has implemented Gapless with a FW Update. So what Dr. Biang says about worse SQ when Gapless is running is BS imo.

    16. In many of the reviews here and on all audio and audiophile sites and magazines, people discuss subtle differences between different equipment configurations and setups. The difference between gapless and not-gapless is not subtle at all – even when the gap is tiny, it’s easily noticeable and disrupts the musical attention. Lack of gapless support in the Oppo is a major disadvantage.

    17. I remember the Apple iPod didn’t do gapless playback until the 3rd generation and it needed a firmware update to do it. Now, these new higher-end players can’t do gapless playback is almost comical.

    18. Could not care less. However, it piques the curiosity: what happens, using a gapless player, when the finishing track ends with a thwack _and_ the starting track starts with a thwack? Do they unnaturally merge in a gapless double-thwack whith no silence in between? Wouldn’t that be as annoying (for people so inclined to be) as gap-ed playback?

      • Um, no, there is no “unnatural” silence or non-silence – it just sounds like the music it is and was supposed to sound like before the invention of “gap-ed” playback…;)

    19. Thanks for this! I was one of the PS Audio Bridge owners ready with pitchforks. I had never heard of “gapless” playback, because it was a non-issue on any device I’d every used.

      It is 100% critical to music reproduction not to introduce gaps.

      Audio manufacturers are nuts. They lower noise from -95 dB to -105 dB, and it’s a big deal. At the same time, they add noisy fans or power transformers that hum, and they don’t think twice. How in 2016 anyone can be making a device that fails at gapless is beyond comprehension. Yet Classe, Oppo, and HiFiMAN are — others, too. How can they be so out of touch with reality?

    A new generation calling: the utterly marvellous Peachtree nova150

    UPDATED! Tidal support ‘coming soon’ to selected Astell&Kern DAPs