Midi: An Orchestra at Home

Version française...

If you have visited the website of La Scena Musicale, you will have noticed a link called "MIDI files" and may have wondered: What do they do?

Music has always evolved hand-in-hand with technology. If it took several thousand years to go from the first buccina to the modern horn, a few centuries were enough for the rebec to give birth to the violin. In the last few decades this evolution has become so fast that it is easy to get lost. Therefore it comes as no surprise that many readers have only a vague idea of what MIDI is.

MIDI stands for "Musical Instrument Digital Interface". As the word interface implies, it permits exchanges of information between different parts of a system. If we take an acoustic piano, for instance, the keyboard and internal mechanics are the interface between the musician and the strings. Similarly, MIDI is a protocol designed to allow digital musical instruments to communicate with each other. All the computer soundcards currently on the market also act as MIDI interfaces.

A MIDI file contains the notes of a musical work and how they should be played. By analogy to an orchestra, MIDI language is both the score and the conductor.

The most interesting aspect of MIDI is that it is a wonderful tool for the creation and learning of music, from ear training to music theory to the mastering of a particular musical style. These purposes require various types of computer programs. We will look at three.

The sequencer permits the user to record an improvisation, composition, or the performance of a score and then to modify the arrangement, instrumentation, or any other aspect of the performance. Let's say you have just played divinely a Beethoven sonata, but here and there you have hit a wrong note. No problem: as with a word processor, you correct your typos; here you delete the undesirable notes. Transposition and tempo changes become child's play. With cut-and-paste you repeat or reorganise the sections of a piece as easily as you would the paragraphs of a text. The piano is very nice, but maybe an organ would be better, so a click of the mouse and there it is. A sequencer works like a multi-track tape recorder in that you can add as many parts as you wish. You can also mute any track, for instance the piano part of a concerto, thus allowing you to play the solo yourself accompanied by the orchestra.

Notation software enables you to create, edit, and print a musical score. The inputting of the notes may be done with a mouse, computer keyboard, or MIDI. The more elaborate and expensive the package, the greater the number of musical symbols available. Cut-and-paste, transposition, and playback are among the basic functions of all notation packages. Notation and sequencer programs together are excellent tools for the in-depth study of a musical composition.

The arranger generates different accompaniment parts from a few basic facts about the desired style, key, and chords. For example, it is possible to choose a key and type in the desired chord progression using a computer keyboard. The program then plays the chords with a bass and drum part. Following the selected style, various additional instruments may also be heard ‹ but not the melody line. That is left for the user to sing or perform. Chord charts for many songs are included in these programs and it is possible to buy more. Likewise it is possible to add new styles to the library of those already defined.

For the audio playback, two elements are required: the appropriate computer software and a synthesizer. In general, Windows and Mac computers support these elements without requiring any additional equipment. In contrast to a music CD that sounds more or less the same on any system, the sound quality of a MIDI file varies enormously with the quality of the synthesizer used to play it. With a low-end soundcard the sound is barely passable, the drums sounding like popcorn and the piano like a toy xylophone. On the other hand, with a good sound card or an average synthesizer, the experience is satisfying. With a top-quality sampler or synthesizer, the sound reaches the spectacular.

This article only scratches the surface of the wonderful world of MIDI. In the coming months I hope to be able to explore it more fully with you