How can I test how MIDI is travelling between my iOS device and my Mac?

Recommended (free) apps for testing

MIDI Wrench
This app allows you to see incoming MIDI data from any port and send MIDI to any port usingthe knobs and keyboard on the bottom. This is very helpful to check MIDI sending and receiving but also to verify what port name the info is moving on.

This program allows you to select ports for sending and receiving MIDI data on Mac OS. It also has a small keyboard on the bottom to send note data.

How to use

In this article we will assume an iPad is in USB Port 2 and a computer is in USB Port 1.
  • To test that the connection from the computer to the iPad is working use MIDIkeys
  • By default, to send from the computer to the iPad you would simply select USB Port 2 as the output/destination port
  • Select Destination dropdown menu to be USB Port 2 and use the keyboard on bottom of the program to click notes
  • On the iPad have MIDI Wrench open and in the right side box you should be seeing note and velocity data coming in
Your setup should look like this:

As you can see we have selected a few notes and the MIDI Wrench app has detected this. This means the data is flowing.

The next part is usually where you can see if there is a problem in the setup.
  • Use the keyboard at the bottom of the MIDI wrench app to send MIDI back to the computer
  • On the computer in the MIDIkeys program use the Listen to port dropdown menu to select the default port of USB2
  • The keyboard on the bottom will light up keys in green when data is coming in
  • If you do not see MIDI data coming in try selecting another port from your interface to see if the data is coming through on another port name
You may notice that a different named port works (for example ETH3). This means that either the iOS device is reading the wrong naming or the computer is. If the computer  name is wrong please follow the advice in this article. 

If the iOS device is not updating the naming, the only way to fix it is to completely wipe your whole iOS device and connect it so it will be rescanned as a new device. 

If you do not see any MIDI on any ports using this method you should verify that the iOS device is seeing the interface in some form by going to Settings > General > About on your iOS device and making sure the interface name is showing in the list there.