Introduction to MIDI and Computer Music: Interactive Application: MIDI Messages
This application covers the basic structure of MIDI messages, as well as some details of the channel voice message types, including note-on/off, aftertouch, control change, pitch bend, and program change messages.
Download the application as a .zip archive, and uncompress it if necessary. It will probably be in your Downloads folder. You can run it from anywhere.
When you first launch this, you will see an alert warning you that the application was downloaded from the Internet. Just say okay.
If you launch the app and see only its menu bar, but not its window, then quit the app and make sure the app name is the original one: “MIDI Messages”. (The name can change if you download more than one copy of the app into the Downloads folder.)
This app has issues: