Musical Instrument Digital Interface
So: How does one compose music, using a computer as a tool?
The first thing you need is
something to play/compose the music on. This will be a musical instrument
with a MIDI connection. MIDI stands for "Musical Instrument Digital
Interface". It is a jack (or, more likely, a pair of jacks) usually located
in an unobtrusive spot on the instrument. The most common MIDI instruments are
keyboards. These are the modern evolution of the old electronic organs people
used to buy. They can mimic upwards of one hundred different musical
instruments, ranging from the obvious (piano and organ) to the non-obvious
(guitar and guitar fret noises, string sections and horns) to the exotic (sitar,
bird tweets, bottle flutes). Depending on the quality (and age) of the digital
keyboard, the instruments may sound phony or uncannily realistic.
For people who do not prefer traditional keyboards, there are also MIDI
saxophones, MIDI guitars, MIDI flutes, and so on. Each is played like the
traditional instrument on which it's based; however, most of them do not create
sounds acoustically. They must be plugged into an amplifier in order to hear
them.
Record a Composition
The purpose of the MIDI interface is to plug the unit into a computer (or,
less often, into other MIDI devices for reasons I won't go into here). Thus, it
becomes an input device, just like the usual alphanumeric keyboard, to
communicate information to the computer. Just as the regular keyboard is a
natural way of inputting the written word to a computer program, a MIDI device
becomes an intuitive way to input musical performance information. A MIDI device
and a computer then become, at their simplest, the modern equivalent of a player
piano, since the computer can record the original performance and then play it
back through the original device (or another, compatible, MIDI device).
Since I took piano lessons as a kid, the piano keyboard is the most natural
way for me to play music-even though I didn't take a lot of lessons, and can
only play in the key of C. So I bought a Yamaha, and that's what I used as my
primary musical input.
By the way, it is possible
to get a MIDI keyboard that cannot produce any sounds; it is also possible to
buy a "sound board" that only produces sounds and must be connected to
a MIDI keyboard (or other MIDI device) if you want to play anything. Most
computers have sound boards built into them, or varying quality.
Now, some keyboards (including mine) have additional capabilities that make
it even easier to generate a professional sound. For example, my keyboard will
let me play simple piano-style chords with the left hand, and it will actually
generate an entire accompaniment in the appropriate chord for me, in a wide
choice of styles: rock, country, waltz, samba, and hundreds more. (There are
actually twenty variants on rock 'n' roll style on my unit.) The accompaniment
includes rhythm, a full drum set, fill (usually strings or horns) and sometimes
even a choir (voicing "oohs" or "ahs"). When the computer is
connected via the MIDI connection, the accompaniment can be transcribed as well
as the melody.
Did I mention the melody can, if I wish, have a full four-part harmony
generated in the appropriate chord as I play, and be transcribed as well?
In other words, the
keyboard functions as a complete orchestra, composed of musicians who are not
"on the clock", and will do whatever I ask of them, as long as I can
ask in terms of simple chords and melody. And the computer will record the
entire performance (including how hard I hit the keys, which affects how that
instrument sounds).
Arrangements
An alternative to playing the music, is letting a computer program generate
appropriate accompaniment. One such program is Jammer
Pro, which I like very much in spite of its slightly non-standard Windows
interface. I often use it to provide a basic accompaniment, to which I then add
layers from the MIDI keyboard or even by hand.
The next piece of the puzzle is the program running on the computer, to do
the transcribing. The one I use is Cakewalk
Pro. MIDI instructions are very low-level (high C pressed this hard, for
this long, high C released this quickly) and, while Cakewalk allows me to view
them directly, I rarely do so. Instead, I can look at the transcription in
"piano roll" view, in which it appears as a series of
"perforations" on a long sheet of paper, or standard musical staff
view. Piano
roll view is generally the most useful to me, since it provides a finer degree
of control than does traditional musical notation--though I sometimes use that,
too.
Each "instrument" sent from the keyboard is placed in a separate
channel. Most MIDI devices are limited to transmitting or receiving 16 discreet
channels; however, Cakewalk allows me to control many MIDI devices at once, with
16 channels for each.
After the original performance has been transcribed, the software allows me
to modify it, just as a word processor like Microsoft Word allows me to edit my
text after my initial inputting of it. I can make any particular note play
louder or softer; start earlier or later; last longer or shorter. I can also
move the note (C to a B#), delete it entirely, or add a new note I didn't
originally play.
After making a change, I would want to hear the result. The software allows
me to play back the (modified) performance-at normal speed, or slowed down or
sped up, if I prefer.
It also allows me to add lyrics, which will appear with the notes in Staff
view, and print, if I want to create sheet music for the song.
So…to take one example, "Don't Think I Can Take
This," from my album, The Man Who Isn't There: I had brought the
keyboard with me to New Jersey when I was teaching a class there. While eating
dinner in the restaurant, some lyrics occurred to me which I jotted onto a
napkin. By the time I got to my room, some of the melody had occurred to me. The
actual composing process is the same as it ever was; I played notes, tried this,
tried that, until I found a tune I liked. I then tried playing it in different
styles: light rock, Latin, strummed guitar, and finally decided it sounded best
with a country-style accompaniment. I practiced it enough do that I could play
it consistently.
Then I tried singing the piece. I can only play in the key of C, but if I
need to transpose to another key so that I can sing the melody I made up, the
keyboard can do that, too (as can Cakewalk Pro). I simply tell it how many notes
up or down to transpose, and it does the math, so to speak.
I then plugged the keyboard's
MIDI interface into my laptop, and ran Cakewalk. I told Cakewalk to begin
recording, and played the song. That gave me about eight channels of
instrumentation: a simple, basic, arrangement of the song.
The accompaniment is always perfect (as long as I hit the right chords), but
I don't usually play well enough to get a perfect performance of the melody. So,
I corrected whatever notes I didn't play right, so that I ended with a perfect,
basic, arrangement.
Click here to download/play
the MIDI arrangement of "Don't Think That I Can Take This".
My technique is to then sweeten the arrangement by adding more layers of
instrumentation. For example, the basic accompaniment may include strings
(called a "fill") but many songs need a string counter-melody, as
well. So I tell Cakewalk to record a new channel while playing back all the
other ones. On the new channel, I add strings, or a flute, or whatever. And I
repeat this process until the accompaniment is no longer basic: It is a full
orchestration of the song, the way I want it. (This process may take more than a
day. I often tape record the arrangement and play it in the car while I drive,
over and over, to see if I "hear" places where more, or different,
notes or instruments would improve the arrangement or orchestration.
It's also easy to alter the instrumentation without changing the notes. For
example, maybe an English horn doesn't sound right at this point? With a click
of the mouse I can try a French horn in its place, or even a violin or
xylophone. Same notes-held the same time-but with a different sound.
I can also copy part (or all) of a track to another track, letting it play as
a different instrument.
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