In this bold, new future of computing, we don’t need USB or ports, huh? Wait – scratch that – you may have your iPad and your USB, too, after all. Photo (CC) Teo.

Score one for standards. According to second-hand sources and a post to a public mailing list, the upcoming Apple iPad accessory adapter for cameras, the iPad Camera Connection Kit, will support audio interfaces that are compatible with the USB Audio Class. I don’t have official confirmation from Apple, and the adapter itself appears not to be shipping until later this month, so file this as “likely, but unconfirmed.” But it’s one to watch, and comes as a surprise to me. (Generally, camera accessory kits aren’t a way of providing audio expansion.)

Let’s assume, as these sources suggest, that USB audio devices were available via the standard stereo output (or even input) for the public Apple APIs for audio I/O. In that case, the other good news is that iPad apps would be able to support your third-party hardware without special modification of the software, or a signed hardware license agreement.

Most pro audio interfaces are not class-compliant; it’s more common to use custom drivers, even for USB 1.x-compliant interfaces. Custom drivers would be out of the question. But there are a number of interfaces that do provide class compliance, like the M-Audio Fast Track or Edirol UA-25. (I have a Cakewalk-branded, Roland-manufactured SPS-25 that works as a class-compliant device with the “advanced” mode on the back switched off.)

Incidentally, devices that support this spec will also easily work with Linux, and possibly upcoming updates to Android, if the latter adds similar USB host support. That means there’s now ample incentive for audio interface vendors to investigate providing class support, as it could mean more customers not only from iPad owners, but owners of other slates and tablets, too – including those we don’t yet know about. (Google tablet, anyone?) That further illustrates why up-to-date class descriptions for hardware are so badly needed (though it also, sadly, reminds us how much isn’t covered by these generic classes).

Before you get excited about connecting a MIDI keyboard to your iPad, I don’t know that this will mean support for the MIDI device class. But it’s nothing if not a reminder of the power of standards. (See also the Nintendo Wii remote, which enterprising musicians have used as a controller on multiple operating systems, thanks to its support for the Bluetooth spec.)

And yes, this means the prospects of the iPad becoming an all-in-one, live performance machine are looking brighter. DJs are still likely to be unsatisfied, as I doubt that this will allow separate audio cuing, but given that I didn’t see this coming, who knows?

Supporting evidence:
Re: iPad USB Audio Class 1 and Update on OSX Class 2 [Apple Core Audio API Mailing List]

Thanks to Art Gillespie for pointing this out. He’s got a connection kit coming, so expect a full test.

  • Tony

    so I can buy an ipad and hope an accessory hack will give me MIDI, or buy an HP slate, and know it will work. hmm….

  • A couple notes:

    No support for MIDI.

    Unlike the iPhone, there's no analog audio in on the iPad dock connector. There's only analog mic input from the headset jack.

    Specific apps may have to be modified to support this, but it's exposed in Core Audio.

    Power might be an issue for many devices. The iPad USB provides only 100 mA. Although a powered USB hub might solve this problem.

  • salamanderanagram

    so if i read correctly, you'll be able to connect an external soundcard? this sounds kinda useless in that it'll just drain the battery life almost immediately (maybe i'm mistaken?)…

    for a second i was all excited and thought you'd be able to plug into yr computer and use it as a controller without a janky wifi connection but that would be too awesome to be true i guess.

  • Well now… That would be the awesome, wouldn't it?

    While on the topic of somewhat unexpected things on the iPad, has anyone else noted the lovely audio/video experience that happens on Tap Tap Radiation's "high score" screen?

    Drag across the surface for a lovely fading tracer effect accompanied by glass harmonica sort of tones. Would love to see iPad music apps that combine synthesis with visuals and creative multi-touch in this way rather than emulating a keyboard, mpc pads, etc…

  • For what it's worth, unless something's changed at Apple, I don't think you can get more authoritative confirmation on Mac/iPhone OS audio issues than from Bill Stewart, the author of that reply.

    And sorry to be the bearer of bad news, but there's no question on MIDI: He stated earlier in the same thread that MIDI isn't currently available. (This makes sense—supporting USB Audio doesn't require any public API changes… MIDI would.)

    I agree it's unfortunate we're only getting 2×2 i/o, but then again, this morning I woke up in a world where hardware accessories for the i-Devices could only be accessed by their manufacturer's software. So, like you say, score one for standards!

  • I'm not sure that this really shifts in any fundamental way the observations we've already made about hardware. If it's hardware flexibility you're looking for, I have pretty simple advice — perhaps even *objective* advice — wait. Don't get the iPad. Not by any stretch could I imagine someone saying it was the device's strength. (And it has a lot of really significant, admirable strengths. It's just not a device designed for connecting a lot of different hardware.)

    That said, for people who like the iPad as-is but have been frustrated by the quality of the audio output, this is a huge potential loophole. So kudos to the Core Audio team for making it happen, and to Apple for building that core competency they have into their device.

    And, to look at it another way, the beauty of this is that the device vendors – assuming they actually supported the USB class standard – didn't have to do a single thing. It's automagical compatibility, and they don't even have to do any testing. For the past few years, every time I've talked to a device vendor, I've asked about class compliance for USB audio devices, and gotten semi-blank looks. It's not entirely their fault – as Art notes, 2×2 I/O is fairly limited, and as I allude to in the story above, USB 2 didn't even get an expanded audio class. But even a limited standard is better than no standard.

    I make it a footnote here, because it's not worth crowing about until there are more devices, but it also means that by supporting the USB class, you get support with the iPad and with Linux and Android tablets you haven't seen yet. Normally, supporting things in the future *isn't* such an easy matter. With standard device I/O, once you do the hard work of supporting the standard, everything else falls to the makers of those computers. And since companies like Apple, Google, HP, Asus, and such are an order of magnitude bigger than the biggest music tech company, that's a big deal.

  • @Tony — it's not a hack. It's supported. Technically, you shouldn't even need the CCK; Just slap a M->F adapter on the port connector's usb end, plug a hub into that (so that the iPad is the hub's host) then plug the device into the hub. If I had a class-compliant USB device handy, that's what I'd be doing right now. 🙂

  • If I can get my hands on an iPad Camera Connection Kit, I'll test this out with my Edirol UA-1EX which I believe is class compliant in non-advanced mode.

  • mediawest

    have any of you noticed on these devices that latency of any of these apps? it like standing 15 feet from you ipad, as it has about a 15ms lag….. you cant run any apps that you will want to use professionally on a ipad, you might be able to use it as a control surface for your DAW of choice….

  • Dub

    I just bet it won't have stereo line-in.

  • Paul Norheim

    Something like the Apogee One would be fab. It is "Core Audio compliant", but perhaps not "class compliant"??

  • Damon

    I gonna take hope that apple will begin opening stuff up in time. Maybe they just want to bottle neck the whole iPad code boundary thing until they feel they have a solid consumer customer base. Make sure they have a rock solid command line before they let loose those zany creative product and development persons. iPad premise, the Beta Years. Maybe that is a bit idealistic, but think the creative spirit will win out long term.

    The fat man walks alone.

  • @mediawest I don't know about the iPad specifically, but when using the iPhone I have the feeling that most of the lag is in the multitouch screen. A button interface, like a bluetooth gamepad or something, perhaps could give us a closer estimate of the actual audio latency.

  • Is the audio signal noisy on the iPad?
    This would become really cool the day it'd support multi channel audio interfaces. Either way I'd be the perfect audio FX buddy for any live sound engineer 🙂

  • Bill Stewart is the source here so I would guess that this is a done deal. Ordering one right now and will be supporting it in our softsynth for iPad. I need to remember to read my CoreAudio mail more often. =)

  • @Paul Norheim Apogee devices use custom drivers so you are a bit out of luck. But you could always run the headphone out into those legendary Apogee preamps =)

  • Paul Norheim

    Christopher, I don't own the "One" (I have the Duet). But Apogee cooperates with Apple, and it would be nice to see an Apogee interface specifically developed for the iPad.

  • Yes they are very synergistic with Mac hardware. I had the opportunity to use an Apogee Ensemble for a performance I assisted with.

  • I want to ask Bill if there are plans for support for the iPad AS an audio interface in MacOS X — it shouldn't even require the camera kit, just the standard usb adaptor.

  • As I understand it, someone like Apogee would have two options: either a) do a class-compliant device (which we'd all thank them for, by the way!), or b) actually become an iPad/iPod hardware licensee and go the dock connector route.

    To be honest, though, I'd be surprised to see them do either one. Even option (b) is limited in its capabilities versus what they can do with custom drivers on desktop Macs.

    Some of the USB audio interfaces out there are fine, though. And "noise" isn't an issue; you'd be entirely bypassing the signal flow out of the iPad and streaming audio directly over USB, constrained only by the quality of your box.

  • dtr

    must be the 1st time you beat the Mac fanboy sites with a scoop 😉

  • @dtr: Well, it's been a while. 😉 Working with Apple generally means playing by their rules – no scoops, so much. This is different, as it happened to come out in a public mailing list.

  • If Apple can enable audio interface via the camera connection kit… why don't they enable audio/video streaming so we can use a webcam with it..

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  • bliss

    @Christopher Penrose

    OT: Any chance of updating Hyperupic? 🙂

  • HEXnibble

    Thanks for the scoop, Peter. This is very promising!

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  • Aaron

    What a backwards ass world we live in that people would even tolerate something like this rather than just wait for a product to hit the market that will better suit their requirements and needs. Then again, better products aren't exactly trendy or don't always have the Apple logo on them so some ppl will be lost forever..

  • lemmy

    Aaron, the iPad is a fantastic device. You clearly have not used one.

  • keats

    Create Digital iPad.

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  • What about Bluetooh and WiFi? Do we really still need USB?

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  • salamanderanagram

    @vidar, haven't tested personally but also am really not interested in using bluetooth or wifi for live performance… USB just seems more reliable and (my guess) less latency.

  • salamanderanagram

    in terms of audio out too, it's not like you want to send 44100 pieces of audio info per second out via bluetooth and try to put them back together on the other end. that's just insane.

  • HEXnibble

    Using apps like TouchOSC wirelessly have proven to be reliable in live performances with no noticeable latency. I'd rather not risk getting a usb cable yanked out while performing.

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  • I can't wait to pick up my new Ipad ! I will be getting mine as soon as they decide to release it.I did stumble upon this article this afternoon:… But i think everything should be fine. Just like anything you get used to it after you own it for awhile. Take care.

  • Bliss, send an email via and ask about Hyperupic.

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  • blop

    enough of the ipad…

  • USB for the Ipad, now that would be nice

  • I wonder how many USB outlets will be on the Ipad, hopefully at least 4.

  • HEXnibble
  • Tim

    Anyone have a chance to get some hands on time with this to try it out?

  • John

    Well what about wireless midi?? over wifi maybe just an idea

  • Damian

    @salamandergram- Wifi latency on iPad is barely noticeable with a dedicated computer to computer network setup.

  • Hamranhansenhansen

    > so I can buy an ipad and hope an accessory hack will
    > give me MIDI, or buy an HP slate, and know it will work.
    > hmm….

    Where can you buy an HP Slate?

  • Hamranhansenhansen

    > What a backwards ass world we live in that people
    > would even tolerate something like this rather than
    > just wait for a product to hit the market that will
    > better suit their requirements and needs

    I replaced a Zoom H4n with an iPhone 3GS running FourTrack and it was a much, much better pocket recorder for me. iPad is the same thing but it has an 8 track called StudioTrack. These are by far the best songwriting tools I've ever owned. There isn't anything better. In a few seconds you can start a session and the whole device turns into a recorder/mixer with faders and transport controls, it's totally friction-free to use. Ridiculously long battery life, tons of solid state storage, no noise, and so small and light you can have them with you all the time, ready for when inspiration strikes. When I'm done writing, I sync with iTunes, then copy the files from iTunes into Logic Pro and start a production session, it is a joy to work this way.

    There is a $10 iPad app that turns it into a Logic Control also.

    I don't think you're going to see another 700 gram, 10 hour battery, multitouch computer with thousands of music and audio apps for a few dollars each for quite some time.

    Enjoy your wait, though.

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  • John Silverman

    I totally agree with you – but what about I/O? I've hacked a couple of mic in cables for my ihpone but in trying to record live music I get too much input gain and distortion. The Phone OS doesn't allow adjustable input gain (so says all research) so my next step is to hack up a resistor box so I can passively attenuate that mic. Anything battery operated, like a little mixer, would defeat the cool "whip it out and work" aspect.

    So I suppose I'm answering my own question: having to connect the camera adapter, a USB audio interface, AC power for the interface, and of course, mics, would be acceptable for the larger ipad paradigm, but maybe not the phone.

    I have access to an ipad, so I'll order the kit and see if it works with my PreSonus Fireface, which I believe is class-compliant. I'll report back!

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  • Brent Davis

    I just had success using a Shure X2U interface on my iPad. It only works with a USB hub to supply power. With that interface, I can plug in any mic I want, including phantom powered. The interface also has a headphone out to allow you to monitor the input without latency. Problem is finding a tool that detects it properly. "AudioTools" still thinks it is the internal mic.

  • Qasim

    I know this is an old thread but was wondering whether anyone's successfully managed to use the camera connection kit to get multichannel audio out of the iPad – would love to start using mine as a backup dj device but need a second stereo channel set for a headphone/cue…


  • Cxxron

    I have a zalman 5.1ch external sound card that i bought after my old asus laptop stopped outputting sound via the headphone connection. i tried it with the USB camera connector and it outputs sound through optical and 6 ch.