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MidiWorld
"MIDI" stands for "Musical Instrument Digital Interface" and the emphasis here should be on "Musical Instrument." The process of synthesizing a musical instrument's sound into a digital signal has been around for a while, longer than the PC has been around. It was found that a computer could take a "sample" of the real sound waves of an instrument and from that sample, make any sound the real instrument could (and many it couldn't). This opened a whole new field of music and an industry that designed "synthesizers" (usually in the shape of complex synthesizer keyboards) and ports to interface these synthesizers to a computer..."MIDI ports." The flexibility of the computer to process sampled instrument sounds, combined with the synthesizer/keyboard to generate these sounds, quickly found its way into commercial music recording sessions. A "sample" of the string section of a symphony orchestra, sounded just as good as the real thing and could be played back on a midi keyboard by one person, eliminating the need to record at a music hall with a live orchestra, thus saving time and money. The computer could modify the sound to include things an orchestra could not do, such as echo and chorus effects that an artist may find desirable in a recording. Of course, all of this cost big money back in the early days of midi. Most of the synthesizers were custom made and used mini computers to run them. The term "PC" was just in it's infancy. Of course the PC came along and things changed fast. Games were the motivating force behind the music in a PC and since games were popular it didn't take long for music to become an expected element (along with sound effects) of the game. Early on, PC's used a process called "FM Synthesis" to produce music. A music card could be purchased for a reasonable amount of money that would produce FM music. One of the first FM cards to become popular was the "Adlib," which used the Yamaha FM chip. (The original chip's predecessor is still used to this day on most sound cards) It did not play sound, just FM music. FM music was a "good" attempt to reproduce musical sounds with a PC but it clearly lacked the fidelity and realism of MIDI. FM music was created by "beating" two frequency modulated (FM) waves against each other and listening to the result. This third wave (known as the "beat frequency") when played back could be made to sound like an instrument. Although the sound is clearly "synthetic" in nature and one may have to stretch their definition of (say) a piano, to believe the sound from an FM card is that of a piano. Another card that was very popular was the "Game Blaster" from a newly formed company known as "Creative Labs." Soon after, Creative Labs made a stereo version of the card and put a sound chip on it, they named it "Sound Blaster." I don't think I need to tell anyone about the Sound Blaster. Unfortunately, even with stereo and sound support the "Sound Blaster" was still just an FM card (and the "low end" models still are to this day). This meant one would have to contend with the FM sound from the card. If you wanted MIDI you had to shell out more money to get a midi card to compliment the FM card for your computer. Fortunately, this problem did not last long. The manufacturers of MIDI cards realized the market for MIDI extended beyond just commercial recording or the individual user who had the resources to afford a midi synthesizer. The PC was now a household word and computer games needed more than the "toy box" sound that FM synthesis suppli ed. A company named "Roland" manufactured a synthesizer that could be plugged into a PC and play back MIDI files. The device used a proprietary port to interface itself with the computer, the MPU-401. To this day we use this standard for midi ports on a PC. In no time, internal MIDI cards were being manufactured and some companies (Turtle Beach for one) went a step further and manufactured "add on" cards that complimented an FM sound card. In spite of an FM sound card's short fall's in the music department, it is still used for sound. The combination of a good sound card and a good midi "add on" card makes for both great music and sound. Most sound cards today come with both MIDI, FM Synthesis, and sound built in. It's easy to find out if the card you have or want to buy has MIDI capability. The box or documentation will indicate that the card is capable of "MIDI" (of course) or it may say "Wave Table" Synthesis. The term "Wave Table" was derived from the table used my the midi card to look up what instrument should be played on the "instrument channels" used by the card to select an exclusive channel for each instrument (or "voice"). You will see that your midi card has a certain number of "voices" it can play at once. This indicates how many instrument samples it can play simultaneously. Another thing to look for in a midi card is the amount of memory on the card. Because the card uses pre recorded sounds, they must be stored in memory on the card. This is usually done by loading them on a ROM chip. Of course the smaller the rom chip is in capacity, the less it will be able to store. The result will be fewer instruments to play or a reduction in the quality of sound because of compression used to store the sound banks on the smaller capacity rom. Many MIDI cards have the ability to support "add on" memory. For a few dollars you can buy additional sound banks that are bigger and more realistic to load into the added on memory. A good rule of thumb is to get a midi card with at least 2megs of ROM based samples on it and memory add on capability to support downloadable "sound banks". Today most Midi cards follow the "General Midi" standard. This is a "pre-defined", industry standard "table" of instruments that is used by all manufacturers of Midi cards. This assures that each channel on the midi card is the same "industry wide." This way company "A" will have a Piano on channel one and so won't company "B" and so on. It would be a bit aggravating if you bought a card only to find it would only play correctly with a limited number of games/files. This used to be a major problem between manufacturers. With an industry wide "standard" the problem has been eliminated. A bit of a footnote to "General Midi" is in order here, although all manufacturers agree on what instrument to put on what channel, they still have "tonal differences" so a piano from company "A" may not sound the same as the one from company "B". These differences can be overcome by downloading "Midi Banks" (also called "Sound Font" banks by Creative Labs and E-mu) These "banks" are just different samples of the same instruments. For example, a sample of a Yamaha Piano will sound different than a sample of a Steinway. By downloading a Yamaha Piano to the "Piano Channel" you can be assured that the sound you want will be what comes out of the MIDI card. This of course is not a "standard" but many specific instruments can be found on Midi manufacturers net sites. A good example of this is "E-mu" the makers of the Midi chip for Creative Labs. They have several CD's available with a variety of instrument banks. This gives the midi owner the option of changing the "tonal qualities" of the instruments he or she wants to hear from their card. |
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