MIDI over USB

[arlo]

I often get questions about sending MIDI over USB and want to make sure I'm giving the right answer. Can anybody clarify this for me?

My understanding is that if you want to connect to a MIDI device that has a USB port, you can use the Camera Connection Kit and a USB cable instead of a MIDI interface and a MIDI cable. However, I've heard that this does not work with a Roland GR-55, which requires a USB-to-MIDI cable instead.

Is there a general rule about when you can send MIDI directly over USB, when you can use a USB-to-MIDI cable, and when you need a real hardware MIDI interface?

Or is it necessary to check with the manufacturer of every hardware device to be sure?

[Christoph]

From my experience, there is no general rule. You have to check the specific device combination. For a MIDI device to work with the camera connection kit, it has to have a USB connector, it must be class compliant (does not need specific drivers) and it must draw only a tiny amount of power from the iOS device. There was an extensive list of compatible devices on iosmidi.com, which unfortunately is not online any more. But you can find it here thanks to the WayBack Machine: http://web.archive.org/web/20130128055004/http://iosmidi.com/devices/

What type of MIDI connection you use depends on the available outlets on your specific device: If it has the traditional 5-Pin-MIDI Connectors, you need a MIDI interface. A "USB-to-MIDI cable" is nothing else than a MIDI interface, just one of the simple sort. If it does not have the MIDI connectors, but only a USB connector (e.g. most of the desktop MIDI keyboards) you would use a simple USB cable, but it does not always work. Using a powered USB hub and if available a "generic" driver setting helps in some cases.

All in all, I recommend not to use the camera connection kit, but instead a MIDI interface that is specifically made for iOS devices. Simply because of two reasons:

• Fragility: Set List Maker is made for the stage. Stacking up the camera connecting kit and some USB connector etc. in a live music environment is a questionable idea.
• Powering the iOS device: You do not want to run out of power during a show. Using the camerac connection kit prevents you from charging your device.

At the moment, my favorites are the Alesis iO Dock and the iConnect MIDI. Both provide reliable MIDI Inputs and Outputs, charge the connected iOS device and are rugged enough to survive a stage show.