 |
 |
 |
 |
|
History of MIDI
Roland, a Japanese company that was developing musical keyboards, was quick to notice the advantages and potential of a personal computer (PC) with regards to creating music. The IBM personal computer at the time had no onboard or built-in sound chip on its motherboard, and since Roland wanted IBM's computer to work with all Roland keyboards, they set out to create this piece of hardware for the PC. Thus, Roland made a sound card that could be attached to the Industry Standard Architecture (ISA), which was a computer bus that was used to connect storage devices such as hard drives, CD-ROM and other peripherals to the motherboard.
When Roland finished this propietary piece of musical interface for the PC, it also came up with a unique hardware circuit and a digital language. This digital language would allow both all of Roland's keyboards and IBM's PC to communicate with each other and transfer data that was being controlled by either the musical keyboard or the PC. Roland would name its new interface Musical Instrument Digal Interface (MIDI) and the PC was named Musical Processing Unit, Model 401 (MPU-401), the first MIDI interface for the computer.
Meanwhile in California, Sequential Circuits Inc., a company that had been making synthesizers since the 70s, released Prophet 600 in 1983, the first synthesizer to implement what is now known as MIDI.
|
|
This vintage piece of gear was an analog synth that could play within five octaves for a total of 61 notes. It produced a bright and harsh sound via two voltage-controlled oscillators (VCO), which meant that the ways the sound could vibrate was due to these electronic oscillators changing the frequecy of the vibration through the amount of voltage used.
As is expected, it also contained two voltage-controlled filters (VCF), which enabled the player to adjust the frequecy of the sound or constrain a sound to specific frequencies. The auditory result is that of overtones; that is to say, when a sound is being emitted only through a limited number and set of frequencies, it may create certain overtones. In the most basic sense, an overtone is the lingering of a musical note after it has been struck or played. After a note has been struck, the vibration that it causes in space fluctuates and creates varying oscillations.
The VCF can be used to "emphasize" certain characteristics of a musical note or a sound and, thus, can make overtones more prominent by
|
|
electronically reproducing the affect such a sound would have on space in real life. Lastly, this synth included two voltage-controlled amplifiers (VCA), which does exactly what it says: it changs the gain, or volume, of the sounds.
Basics of MIDI
MIDI is a very complicated topic that is filled with lots of jargon, so only the basics will be discussed and they will be explained in a simplified manner.
MIDI compatible devices and instruments connect via MIDI cables which consist of 5-pin DIN plugs on either end. An electronic keyboard creates sound by circuitry, and not like acoustic instruments where you need to strike, bow or blow to make sounds. For example, when you press down on an acoustic piano key, it triggers a hammer-like handle inside the body to strike thick strings that are on something that looks like a harp, but when you press down on a key of a keyboard, it sends an electronic signal telling the internal circuitry what note to play and how to play it. This, like on an acoustic piano, depends on what key you play and how fast you hit it, the latter is called velocity.
When you press on a key, a signal called note on is transmitted, and when you let go another signal called signal off is transmitted.
It is important to note that MIDI does not transmit audible sounds, but rather instructions or messages. You can think of MIDI as a musical score, where this tells the musician what to do; a music sheet is a set of instructions and the musician can choose to play them on any instrument.
MIDI acts as a type of music sheet that gives out all the instructions, and the instructions can be executed by any sound sample at our disposal. If the MIDI Out connection of the keyboard you are playing is plugged into the MIDI In of another MIDI device, you are said to be playing the master keyboard, and the other MIDI device is called a slave.
On a simple MIDI setup, there may exist 16 channels, and you can switch from one channel to the other or have any of them on or off in any permutation via the master keyboard. These channels are called modules. These channels are usually sounds that will perform the instructions given by the MIDI device.
Each sound module has a a maximum polyphony, which means that each module can only place a certain amount of notes at the same time. Hence, some notes may cut out or stop playing once other ones are played, if you are holding down more than the number of keys that the maximum polyphony allows.
Typically, there are at least two knobs on the left of your MIDI keyboard; one is a pitch bender, which basically changes the musical note of the current note being played, and the other knob is the vibrato depth, which controlls how fast the note oscillates and how low the volume gets. Of course, there is also a master volume that controlls the overall volume.
|
|
Report
|
|
 |
 |
|