Apollo MIDI over Bluetooth for iOS and OSX

App overview:

Mac setup:

Get Apollo for iOS in the iTunes App Store!

Get Apollo for OSX in the Mac App Store!

Please see the bottom of this page for technical details on Bluetooth LE. There has been coverage of the app in Discchord, Synthopia, and Music App Blog.

Apollo is compatible with iOS 7 and 8, on the iPad3, iPad4, iPad Air, and iPad Mini, and the iPhone 4S and newer. It IS NOT COMPATIBLE with the iPad 1 or iPad 2, or the iPhone 4 and earlier. The app uses Bluetooth LE, which IS NOT AVAILABLE on earlier devices. If you download the app to an earlier device, it will not work. There are significant hardware differences between Bluetooth (which all iDevices support), and Bluetooth LE (which only the more recent devices support). Again, to try to be as clear as possible on this -- Apollo will not work on the iPad 1 and 2, or on the iPhone 1, 3g, 3gs, or 4.

Newer Macs support Bluetooth LE; on older Macs, you may need to install a USB Bluetooth adapter (we have had good luck with the iOGear GBU521 on OS X versions up to Mavericks). There are very few "officially supported" USB Bluetooth adapters for the Mac, and we have no way to test all the possible hardware combinations. On the Mac, you may need to set up an IAC driver, to transfer MIDI from the Apollo desktop app, to other apps that need MIDI. The Mac set-up video covers this topic. With OS X Yosemite, it appears that many USB Bluetooth adapters (including the eager GBU521) do not operate properly; if we find a USB Bluetooth adapter that works reliably, we will include that information here.

Connecting synthesizers and sequencers across multiple iOS devices has been challenging, and there have been few options. For wired connections, you need multiple MIDI adapters (either dedicated iOS devices, or a Camera Connection Kit and generic USB MIDI). WiFi MIDI can have too much latency and jitter, making it unusable for music applications. With Apollo MIDI over Bluetooth, you can easily connect a pair of iOS devices, or an iOS device and a Mac, using Bluetooth LE. Bluetooth LE is designed for low latency -- ideal for music applications.

Simply start the app on each device, select an "A" endpoint for one, and a "B" endpoint for the other, and then press search on both devices. They should detect each other, and connect quickly. Once they are connected, MIDI from one device will be sent to the other -- the connection is bi-directional. On each device, you can select the MIDI destinations that you wish to forward messages to.

When connecting to a Mac, select the "A" endpoint for the iOS device; the Mac will be a "B" endpoint. Just as with the iOS set-up, press search on both devices, and they should connect quickly. With MIDI routing on a Mac, there is a danger of creating a loop in the routing (where MIDI messages get sent and relayed repeatedly). To avoid this problem, Apollo on the Mac either sends MIDI from iOS to the Mac, or vice versa -- make sure that you toggle on the direction you need.

Apollo has been designed to be simple to install and configure, and it should expand your MIDI capabilities easily.

Technical Details

To use Apollo, you will need Bluetooth LE on both devices. Apple began introducing Bluetooth LE (also known as Bluetooth 4.0) around 2011. To be specific:

  • SUPPORTED: iPad3, iPad4, iPad Air. iPhone 4S, iPhone 5, iPhone 5C, iPhone 5S.
  • NOT SUPPORTED: iPad1, iPad2. iPhone, iPhone 3G, iPhone 3GS, iPhone 4.
  • With Macs, it gets a bit more tricky.
    • Apollo runs on OSX 10.7, 10.8, 10.9. Prior versions of OSX are not supported.
        Make sure your OSX installation is up to date. For OSX Mountain Lion (10.8), there is a 10.8.5 supplemental update that may be required; prior to this, there is a known OSX bug that may prevent a Bluetooth LE adapter from working properly. If we find out information about problems with other versions of OSX, we will post them here.
    • With a Mac, you can find out if it has Bluetooth LE support by holding the option key, and clicking on the Bluetooth icon in the menu bar. If the version is 4.xxx, Bluetooth LE is not supported. If the version is 6.xxx, Bluetooth LE is available.
    • A complete list of Mac Bluetooth support is available here.
    • If you have a Mac running OSX 10.7 or newer, and don't have built-in Bluetooth LE, you can use a USB Bluetooth LE (or 4.0) adapter. None of these are "officially" supported by Apple, but many of them work well. We have had good luck with the IOGear GBU 521, but can't guarantee that it will work for all systems. In general, it appears that Bluetooth 4.0 adapters built around a Broadcom chip set are compatible.
    • You may need to set up an IAC driver on your Mac (this is an operating system resource that lets MIDI applications communicate). The YouTube video linked above gives a summary of this. This write-up would also be a good reference.
  • The app uses Virtual MIDI or CoreMIDI on iOS. If you are familiar with MIDI routing on an iOS device, it should be easy to integrate Apollo into your music making. Apollo can run in the background; if you have the app in the foreground, make sure that your synthesizer apps are set to run in the background (otherwise, you may not hear any sound).
  • The apps do not connect automatically; you will need to search on both endpoints to make a connection.
  • On the Mac, make sure you have an IAC driver set up (detailed in the OSX video above).
  • To send MIDI notes to Logic Pro X, you may need to configure the Logic MIDI environment to have a sequencer input. We will post a video explaining this shortly.

Expected Performance

On an iOS device, there's virtually unlimited bandwidth between apps using Virtual MIDI or CoreMIDI. Apps can send as much data as they like, with almost no constraints. When connecting to external devices (using either wired or wireless connections), there are bandwidth limits.

Apollo should be comparable to wired connections in terms of bandwidth, when using iOS 7. The bandwidth with iOS 6 is lower; the effective rate is roughly half of what is possible with a wired connection, but should be more than sufficient for most music applications. The effective latency for both iOS 6 and iOS 7 should be much better than what is typical with WiFi, and close to that of wired connections.

The physical distance between devices, metal obstacles, and other Bluetooth wireless traffic, can impact performance.