Ready to cut the cord and go wireless? With mobile gadgets getting involved in music-making, it seems a logical solution – maybe not reason to throw away your MIDI cabling, but worth at least trying. Bluetooth could be an answer. In fact, it could work even without all those pesky, pricey mobile tablets and phones lying around, just with good, old-fashioned MIDI gear. (‘Bout time.)

Bluetooth and MIDI are a logical match; the big surprise is that these two haven’t paired off (cough) much earlier. We’ve seen the occasional implementation or paper or rant, but not much real-world usage. That could be about to change – that is, provided ample real-world testing.

Bluetooth mobile sync: First off, owners of Korg iOS software just got a Bluetooth-based update that provides sync. (See video below, shot by tipster and reader Danny Fluck.) Entitled “Wireless Sync-Start Technology,” KORG promises their Bluetooth feature now enables two iPads running iElectribe or iMS-20 to sync with one another with zero latency. (The update also includes perhaps more widely-useful features – SoundCloud support and AudioCopy, says Synthtopia.)

The name suggests that what the “sync-start” technique does is actually to match any latency between the two devices so that they start at the same time. That’s how multiplayer gaming typically works, and it applies easily to musical applications: you ping connected devices, then delay the start points of each of them to match the slowest device so that they sound together. (I think I’m saying that correctly and clearly; it’s Friday.)

Danny reports that it works perfectly and “instantaneously.”

Okay, so cool, as long as you only use iPads, and you’re lucky enough to have two iPads handy, and you only use KORG apps, you’ve got a nifty solution – but that’s a little limiting.

Bluetooth MIDI on Android or any hardware device. A bit further-reaching is something Peter Brinkmann, primary author of libpd, has been testing. (See video, top, which is much snappier than my explanation.) Now, Peter is no MIDI fanboy; when several of us talked about adding MIDI to libpd – an embeddable version of the open source patching environment – he described MIDI as a “plague upon humanity.” (I don’t recall seeing that quote anywhere on the MIDI Manufacturing Association website.)

But here’s the thing: MIDI is obsessively compact and simple, and absurdly easy to implement even on the cheapest microcontroller. That makes it ideally suited as a means of making inexpensive hardware inter-operate, and without using up lots of power or bandwidth – just as MIDI was designed to do.

Furthermore, as Apple tablets and phones demonstrated USB MIDI connections, it got Peter (and some of the rest of us) thinking. Yes, it’s too bad that Android devices lack key USB host capabilities that would let them talk to hardware. On the other hand, once you start attaching lots of cables to a device, you might as well use a (more powerful, more flexible) computer in place of the tablet. So low-power, efficient wireless – like Bluetooth – seems the way to go.

Like a good engineer, Peter went and hacked the solution he wanted himself. Partially inspired by Lady Ada’s own, well-documented Bluetooth MIDI experiments, Peter started documenting the process on his blog.

In his first blog post, he describes his hardware setup. (He later updated the rig and moved it off the bread board.

In part 2, he describes latency and jitter. Here’s what I’ve been told by mobile engineers to whom I talked: performance has greatly improved in Bluetooth implementations in recent years. That means that part of the reason Bluetooth MIDI may have been adapted is that, when people first began testing this a few years ago, the implementations weren’t yet good enough – and no one has checked since. (Until now, that is.)

Since then, Peter has released free software for the Android platform, all under a free Apache license, so anyone can try it out. And since it works natively with Pd for Android, this means you can very quickly hook up a Pd patch to Bluetooth support on any Android device. There’s even a sample patch and code to get you started!

As far as I know, Apple doesn’t let you implement a similar solution on iOS, so this would remain Android-only. (Hey, come on – iOS can’t have all the fun.) I’m curious to hear if I have that correct, though, so please do share.

The next step: refining the hardware rig and interface design and most importantly, testing. Correction: I claimed that the MIDI interface was not opto-isolated; it actually is.

Hacklab and testing: With that spirit in mind, on Saturday April 2 from 1p – 6p, we’ll have a free, open hacklab in New York. It’s mainly an informal get-together, but there will be short demos as we go. It’s the first step in broader testing and experimentation with these ideas. If you’re in the NYC area, you can RSVP on Facebook. (just went up, so it may be quiet) The plan is to play a bit with hardware and software and different Android devices.

All are welcome to the hacklab, regardless of experience.

This isn’t just an Android thing, though. Part of the reason to use Bluetooth in place of WiFi is that it’s much simpler and cheaper to implement, and has more modest power requirements. As such, providing Bluetooth MIDI interfaces for other music gear is more manageable than it would be with WiFi.

More resources:

A 2005 IEEE conference presentation describes early work, though this research could use a modern update.

A 2003 open letter encouraging Bluetooth MIDI use.

Meanwhile, in the Land of WiFi

Synthtopia reports on iOS MIDI WiFi, in the case of MoDrum and Bassline, using Apple’s own network MIDI framework. I’m assuming it claims it’s the most extensive such implementation because of the sync functionality.

SoundPrism Pro, in the trailer below, also recently added network (as well as wired) MIDI compatibility.

Incidentally, there are already compatible frameworks for Windows and Linux (in addition to Mac, of course), and no reason Android couldn’t also do WiFi MIDI, too. The advantage of Bluetooth remains doing so with less power consumption, and as direct serial communication over the wireless link.

More resources on the WiFi side…

From January:
New Solutions for Wireless MIDI, MIDI+OSC; Developers Answer Questions

And yes, devices like The Missing Link provide this kind of functionality over WiFi – though the Bluetooth radio could be cheaper and more power efficient. (As for performance, we just have to do more testing.)

Just don’t forget, all of this is a plague upon humanity and an abomination, so try to keep that in mind. Have a good weekend!

  • danny fluck

    this is just too much fun…–s

  • Intersting very intersting… but how would you get MIDI Into a device like an iPad or Android phone? There aren't BlueTooth-MIDI controllers, Are there? (I could be wrong…)

  • ^ So that you don't have to make that adapter pictured here:

  • Peter Kirn

    You do need an adapter, sorry, just because no one yet makes hardware with them. It could be possible to make it smaller than the one Peter built, though; that's just a prototype. Honestly, the biggest thing on them are the 5-pin DIN connectors. So, you could build them male instead of female, and then have something that plugs directly into the hardware.

  • loydb

    I knew my instincts to hold on to my iPad 1 when I got a 2 were correct. Muhahahahahaha!

  • loydb

    Oh, regarding MIDI in, you can use the camera connection kit to plug a USB controller into your iPad — as long as you use a device with its own power (I use  an X-Station).

  • " he described MIDI as a “plague upon humanity.” " 
    lol brings to mind some arnold brocklin imagery.
    yamaha expressed the same sentiment 10 years ago with the introduction of mLan.

  • By the way, when I complain about limitations of MIDI, I mean MIDI as a way of representing music in software. MIDI as a robust way of connecting gadgets is great. Some background:

  • Charlie Lesoine

    iMS20 just got a lot better. You can now control the mixer section with nanokontrol!

  • Em Wilson

    I figure there's enough random radiation bouncing around inside my house and on documented research on the possible long term exposure health risks, I'm sticking to wires and cables for as many things as I can.

    Of course I wear earplugs to concerts and a helmet snowboarding now to, so maybe it's just the age talking 😀

  • loopstationzebra


    Finally. FINALLY.

    It goes to show that perfect MIDI sync is purely a programming issue, and nothing to do with whether or not CoreMIDI has bugs or OSX network MIDI doesn't hold a good clock or Ableton doesn't handle virtual MIDI drivers well or…….

    I can only hope that the guys at FINGER will be willing to share their MIDI success so that the entire iOS MIDI community will benefit.

    As far as Korg? meh. They need to take note of what the guys at FINGER are doing. In fact, everyone needs to take note because they have frankly just set the new standard.

  • Peter Kirn

    I thought I was clear here, but apparently the iOS focus of everybody is making things unclear:

    As far as I know, Bluetooth MIDI is *not* possible on iOS. That's too bad, because as I say, while it's not such a big issue with the mobile device itself, the simpler implementation and lower power requirements make it ideal for cable-free communication *with hardware*.

    Now, I'm not sure about that – because of the requirement to get App Store approval, anything involving Apple becomes a variable. I was actually rather hoping that by posting this, someone would chime in with some educated opinions on what is and isn't possible.

    But the current implementation of Bluetooth MIDI – that is, true, bi-directional *communication* between devices – is available on Android, thanks to Peter's work, and on hardware if you build something like Peter built (and desktop computers, etc.), and the one place it *isn't* available is iOS. I'm happy to be corrected, but that's the current state of things.

    @loopstationzebra: I'm not sure I follow what you're saying, including re: FINGER.

    I don't come to the same conclusion about clock sync. My guess as to what Korg is doing is a simple sync *start*. That is not in any way the same as doing clock sync where you have an ongoing clock signal and you may be unable to adjust latency of either party. In other words, what I would interpret that you're really saying is that you value reliable sync at a fixed tempo over the kind of flexibility of a typical clock scenario — and even over low-latency. But if you're not willing to sacrifice there, you may be disappointed. (That said, I think in many scenarios most people *would* sacrifice those things to do simpler, but more reliable, sync.)

  • loopstationzebra

    @Peter. I'm really after what Finger has just brought: reliable standard clock sync. They've also done something else that no other music app maker has done: gotten two apps to work on one iPad at the same time AND have them both on the same clock. I just did a test, and it worked great. I was also able to get each app running on one iPad – with both responding to Ableton Live's master clock via OSX Network MIDI. I had it running for an hour, with no degradation at all. Amazing. It's the only app(s) I've seen that provide accurate, stable clock sync – for any connection method. The fact that both apps continue working when you turn off the iPad or flip over to another app? WIN. lol.

    My beef with Korg remains to be: They fiddle with this and fiddle with that, but still haven't provided stable clock sync for the iMS-20 via USB or wifi. They still also haven't provided MIDI out support. And with Finger now setting the bar, Korg should really provide a way to sync BOTH their apps on one iPad – as well as a stable sync with any DAW.

    But I don't want to be a poopy pants here: It's incredibly exciting that the Finger guys have been able to do what no one has been able to thus far: Provide rock solid clock sync – between apps and between apps and a DAW. The fact that they are also the first to offer the ability to have 2 apps running at the same time in sync on 1 iPad? WIN. lol. Oh, and you can shut your iPad screen off as well and they keep playing. Double WIN. Charlie Sheen would be so proud of the amount of WINNING going on here. 🙂

  • BassLine + MoDrum seem to work fine over Bluetooth, so apparently CoreMIDI can do that. I didn't expect it to work, but I just turned off WiFi on and iPad and iPod Touch 4G, enabled Bluetooth on both, and the iPad could see the iPod Touch in the MoDrum MIDI setup. Click connect, click clock out on the iPad, click clock in on the iPod Touch, hit play, synced.

    I have no idea what the relative latency/jitter strengths of WiFi vs Bluetooth would be. Bluetooth has the advantage in not needing a network to be present.