"Lectures in Beginning MIDI," part 5

Unhappy sounds -- part 2


Puopuo Having suddenly been handed a floppy disk by Paopao, the young man she met in the forest, Puopuo did not know what to make of this.

Paopao returned to his room, but his heart was still pounding. Never before in his life had he felt this way.
In an attempt to calm himself, he listed once again to the song he had composed.

As he listened, he thought his heart would break. Tears came to his eyes, and he wondered if his true feelings would ever be conveyed to the lovely Puopuo.

Paopao

Floppy disk Returning home, Puopuo showed the floppy disk to her father Paohn, the great composer, and told him how she had met Paopao in the forest.

"Hm, this looks like MIDI data. Let's play it back on my system."

"What on earth!"

The music that flowed from the speakers was nonsense. The great composer Paohn who was a stickler for high standards of propriety was enraged!

"To pass this rubbish off as a composition and try to fool my beloved daughter is an inexcusable outrage!Puopuo, you must never again speak to this boy! I forbid you to go to the forest again!"

ENRAGED

meek Never again was Puopuo seen in the forest.

Although his poor heart was breaking, Paopao continued day after day to compose songs thinking of the beautiful Puopuo.

Ah, what sadness! How could such a tragedy have happened?

The reason is that neither Paopao nor Paohn knew about
Program Change messages or GM.
Gee-Em!

Speaking simply, program change messages are data which specifies a particular sound. Suppose that you are using a synthesizer module such as the MU100, and are creating a MIDI song. Although the MU100 is just a little box, it can play 32 parts independently. In other words, it actually contains 32 synthesizers, each of which can play a different instrumental sound.
Gee-Em
For example you can play a piano sound on part 1, a bass sound on part 2, a flute playing the melody on part 3, and drums on part 10.

But! If you don't specify anything, you're not going to hear the sounds that you expect. You need to specify which sound will be used for each part. The MU100 provides various panel buttons which can be operated to select sounds. So, you might think, all you need to do is set part 1 to a piano sound, part 2 ... sorry! Think again!

With this method, if you give the song data that you created to another person, that other person will need to perform the same procedure before listening. That's not going to work. Data which specifies each sound must be included in the MIDI data itself.
That's what Program Change messages are all about.
Since the settings will be different depending on your sequencer, I won't discuss details here, but suffice it to say that you need to specify the sound number for each part.

Gee-Em

But ... we're not finished yet! Program Change messages simply specify the number of a sound within a synthesizer module. It's not that you're specifying "a flute sound" --- you're just specifying "sound number 74." If sound number 74 happens to be a heavy metal "electric guitar" rather than a flute, you're going to experience the same tragedy that happened to poor Paopao. (The numerical order of sounds within synthesizers is still often different between manufacturers.)

Gee-Em And so! Yamaha and other kindly MIDI musical instrument manufacturers got together to decide on a standard numerical order of sounds, so that the tragedy that happened to the unfortunate Paopao need not happen again.

The result was GM!
Any synthesizer module that bears the GM logo provides the same consistent order of sounds, regardless of the manufacturer who produced it. As long you're using a GM-compatible synthesizer module, MIDI data that was created containing program change messages will playback to produce essentially the same musical result. (MIDPLUG is also GM-compatible. Of course there's a big difference in level, as you can tell by playing back the same data on the MU100.)

So what's this "XG" thing that Yamaha is selling so many of?! Now You can proceed "What is XG!" Ex-Gee!


Text: Shouichi Karasaki (Kamonegi House)

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