What is MIDI?

North Suburban HAMMOND ORGAN Society

When we connect a MIDI keyboard to a computer that has MIDI software installed, all kinds of interesting possibilities become available. These two screen shots below show first one of the ways that music appears when saved as MIDI. Notice the similarity to a player piano roll where the length of individual notes is represented by their horizontal length, and their pitch is related to their vertical placement. To the left is an image of a keyboard so that you can see where the notes are in relation to the pitch of the keys. At this point, if we had a wrong note somewhere, we could just click the mouse cursor on the note and move it anywhere else on the graph where we'd want it. If a note was too short, we could likewise click on it and make it longer (or shorter), and at the bottom, where the vertical lines are, we could select an individual note and by making the vertical line taller, we would increase the volume of that particular note. In the example shown, we wanted all of the notes to have the same loudness, so the vertical lines are all the same height.

Typical MIDI music display on computer screen.

Figure 5.

Figure five, is a screen shot, or picture of the computer screen showing one MIDI track. In this case, it is the first several measures of the melody line of the "Jig" Fugue, by Bach. Notice the horizontal lines representing the individual notes and the image of a keyboard to the left. The vertical lines at the bottom of the screen represent the loudness of the individual notes. In this view they are set to the same value, but they could be varied if we wanted to accentuate certain notes over others. In the lower part of the music "graph" area, there is a virtual transport control panel, where we can operate the system somewhat like a tape recorder in that we can play, record, reverse, or quickly go to the beginning or end and also set the tempo and a loop function if we want the song to play over automatically. Although hard to see in this picture, across the top of the screen are a number of other functions that we can control.

Figure six is another picture of the computer screen, this time showing the first lines of the Jig Fugue melody as real music. Again you will see the virtual transport controller. In this form, we can print out what we played as actual sheet music. This is one of the many nice features of MIDI. If you play something into the system from a MIDI keyboard, you can easily transform it into sheet music

MIDI as conventional musical notation

Figure 6.

As you can begin to see from this, MIDI offers a musician many options. In one sense you might, from a performer's viewpoint, almost consider MIDI as a musical instrument in and of itself, an instrument with the capabilities of control over many different aspects of the final song. To use the correct terminology, every musical piece in MIDI is referred to as a "song," even if the music in question is an instrumental version of a classical number. Sections of songs are referred to as "parts"


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