By Carter B. Horsley
In olden days, a glimpse of cable
was something shocking.
Nowadays, however, it simply means
The Musical Instrument Digital
Interface (MIDI) was created in 1983 by the makers of several
major synthesizers to permit their instruments to trigger sounds
on other instruments, linked by cable, to create a richer, layered
sound. Combine two adequate organ sounds on different instruments,
for example, and, presto, you might get a more impressive and
possibly better sound! All connected instruments, of course, have
to have the same connectors and their hardware guts have to have
been programmed to receive and send data over such connectors.
Fortunately, the creators of MIDI
were far more brilliant than they ever realized for their standard
provided a lot of information transfer electronically via fairly
standard 5-pin cables.
As it evolved, the MIDI cables
were able to transfer data simultaneously on 16 different channels.
Each channel could have 128 categories, or subchannels, of information!
Each category, or subchannel, could have up to 40,000 different
Theoretically, therefore, a musician
could control 16 different instruments, one assigned to each channel,
and play up to 128 notes simultaneously on each instrument and
each note could have up to 128 different controllers and each
controller could have up to 40,000 levels of sensitivity!
That is a lot of information,
and in practice such an network would slow down a bit and might
even "crash," but thankfully most musicians don't have
enough fingers, toes, knees, noses, elbows and ears and the like
to control everything all at once.
What was really spectacular about
MIDI, moreover, was not so much the ability to layer instruments,
but to transfer the performance data of a musician's playing,
as opposed to the audio data coming out of the musician's instrument,
to a computer for storage, playback, and editing.
This capability led directly to
the emergence of the music software industry that produced not
only "sequencer" programs that transcribed the performances
on MIDI-equipped instruments connected by MIDI cables to the computer,
but also the manipulation and even random programming of the synthesizer's
sounds. In time, it has even lead to music notation and composition
programs that can print out performances in standard music notation
and make harmonic transpositions and even stylistic embellishments
of the music played.
Before long, not only were music
instruments being equipped with MIDI interfaces, but also sound
enhancement machines, such as reverberation units, and mixers
and lighting devices.
The possibilities are very broad
and some musicians have applied MIDI technology not only to all
kinds of keyboards, but also to guitars, violins, wind instruments,
gloves, and tap-dance shoes.
Although synthesizers, which are
electronic music instruments, have been around for most of the
20th Century, they did not begin to enter the mainstream until
Robert Moog produced his famous Minimoog in the 1960's. What previously
required a large room fill of expensive electronic equipment suddenly
became available in a wooden case the size of a briefcase and
it produced marvelous, to this day, sounds.
Most of the early synthesizers,
including the Minimoog, were relatively simple with lots of knobs
that changed the quality of the sound and playing their small
keyboards turned a note on or off. Synthesis has come a long way
and the three dozen or so sound controller parameters of the Minimoog
have given way to several hundred sound parameters on some of
the new instruments, which also, very importantly, are capable
of 128 levels of volume per keystroke rather than just off and
on. (Unfortunately, the velocity sensitivity of different synthesizers
varies considerable, but software programs have taken that into
account and can make adjustments if necessary and some instruments
have switchable velocity response settings as well.)
Only 16 different instruments
at one time? That's not much of an orchestra, some classical musicians,
who have not worked with synthesizers, might say. Since, however,
a synthesizer can be programmed to have one keystroke sound like
a 20-piece violin section and since many different synthesizers
can be programmed to respond to the same MIDI channel and since
128 drum sounds can easily, relatively, be programmed to play
on only one MIDI channel, the MIDI orchestra is not all that unimpressive,
especially since one serious electronic musician can play all
the parts, create the composition and its arrangement and notate
it and enhance its sonic ambience and record it as long as he/she
pays the electricity bill.
Furthermore, in the last few years
most synthesizers now are capable of playing up to 16 parts/channels
simultaneously and can produce 64 sounds simultaneously. The number
of sounds can be confusing as some "sounds" are actually
made up of several "voices." Indeed, many of the newer
synthesizers have a "voice" architecture that is composed
of 4 "tones," but different manufacturers are not consistent
in their architectures or nomenclatures. Most 64-voice synthesizers
on the market today can play 16 4-tone sounds simultaneously,
but some sounds can sound quite wonderful with just one tone.
Indeed, the complexity of the "performance" mode MIDI
implementation on the newer synthesizers is quite daunting.
MIDI, then, is a marvelous and
glorified piano-roll of amazing precision, nuance and sensitivity.
Robert Moog's original Minimoog,
which as an analog rather than a digital instrument, was probably
capable of producing a few quadrillion distinct sounds. The newer
instruments have exponentially expanded that sonic universe and
it is safe to say that synthesizers are infinite machines in terms
of their exciting aural universes.
MIDI simply blows the mind and
in the process has made music software the most astonishingly
powerful of all personal computer uses. This is all the more remarkable
because it does not require high-powered processing, unless, of
course, you are using the newer multi-MIDI ports that provide
multiples of 16 channels and have set loose a Rachmaninoff on
a sequencer program in which case a Pentium will be required.
MIDI data is miniscule compared
to digitally recording audio in wav. files. One minute of stereo
audio recording at Compact Disc quality (44,000 sound pictures
per second at 16-bit recording size) takes up about 10 megabytes
of data storage. A 15-minute, highly complex, symphonic MIDI piece
might only take 200K, by comparison.
The Internet explosion is beginning to include some programs that can "stream" MIDI files, similar to RealAudio's streaming audio. Most personal computer soundcards incorporate synthesizers on a chip as well as have the capacity to have MIDI connectors attached. The City Review will report and demonstrate such technology in the not distant future.