Anybody who wishes to venture into making electronic music or who just wishes to record music will inevitably be inundated with strange new terms like S/PDIF, complex new undertakings such as wiring schematics and a seemingly never-ending list of gear needed to make it happen. When people are beginning to build their own studios, one of the most common questions to pop up is, “What is MIDI?” Another is, “What is digital audio?” To some, this is cake; to others, it's worse than trying to learn a foreign language. I can already hear the voices of the hungry-for-knowledge beginners exclaiming, “Somebody please decipher this #*!%* alien code for me!” Like many in music production, I obtained this knowledge through a long process of osmosis, but maybe I can help speed up that process for some of the newbies.
HAL, OPEN THE POD DOORS
The word MIDI is an abbreviation for Musical Instrument Digital Interface and was coined in 1982 at the biannual NAMM convention by a few top synthesizer companies, most notable Roland and Sequential Circuits. Within just a few short years, MIDI became a true universal standard (which still exists today) as the world's major electronic-music-gear manufacturers implemented it into their products. MIDI works like computers on a network: It is a common operating language and physical interface that connects different pieces of gear so that they can communicate. Just as a computer and a printer exchange information, when two (or more) MIDI-compatible units are connected with MIDI cables, they, too, are capable of exchanging information. For example, when a keyboard from manufacturer X is connected with a keyboard from manufacturer Y, the two can talk back and forth. By pressing notes on one, you can trigger the same notes on the other. It is important to understand that MIDI is a protocol for exchanging data, not sound energy in the form of electricity. Sound and electricity do not travel through MIDI cables; digital data does. This is a crucial distinction because it defines exactly how MIDI and digital audio are different — and how you might shape your studio.
MIDI is capable of much more than the aforementioned example. In addition to simple notes, MIDI is capable of transmitting continuous messages such as real-time volume or tempo changes; system-exclusive data (or SysEx, which includes operations such as uploading virtual synthesizer parameters to a computer for backup); and layers of information such as the transmission of different notes for multiple, simultaneous instruments. The multiple layers of MIDI are called channels, and most MIDI gear has 16 channels or multiple groups of 16 (if multiple MIDI ports are present). Think of it like a television set: Turn to channel 10, and a sitcom is on; switch to channel 9, and the news is on; go to 13, and an educational show pops up. With MIDI, channel 1 can transmit a string patch, channel 2 can be a bass, channel 3 can be assigned to control the master volume and so on. Everything is assignable, and that is where the power of MIDI lies.
MUSIC TO GO
Digital audio, in contrast to MIDI, is more than notation and data transmitted between two devices; it is digitally recorded music stored in a computer of some kind as zeros and ones. It works like a guitar and an amplifier: You connect a sound source (such as a guitar) to a recording device (such as a computer with recording software), hit the Record button and play the instrument. What you end up with is digital audio, which can be played back without the original source instrument being present. It is essentially the same as a cassette-tape recording except it is digital.
The beauty of digital audio is multifold. The amount of recording that you can do before “running out of tape” is dependent upon the size of your hard drive. Overdubs are a breeze, and the cut-and-paste arrangement possibilities are endless, not to mention nearly instantaneous. The editing possibilities are extensive, as well, but with that, you need a lot more patience.
MIDI can be recorded, so can digital audio. MIDI can play back notes, note velocity and volume changes; digital audio can, too. MIDI can be multitracked, as can digital audio. So what exactly is the difference? The key here is whether the original instrument is present. When you record an instrument, a voice or a drum machine as digital audio, it is captured forever. You could play for 70 minutes straight, burn a CD and send it to a friend in Japan the same day.
On the other hand, when you record MIDI notes from a keyboard, for example, they are just like notes on a piece of sheet music: An instrument needs to actually play them. MIDI notes recorded into a computer need to be sent back to the keyboard (or to another sound source) to be heard; if the keyboard is disconnected or no other receiving sound source is present, the notes are just blips on a screen. For songwriting and arrangement, however, MIDI can be the clear winner for certain things. When you record MIDI, a single note can be moved around the scale, nudged the tiniest amount in time and lengthened or shortened in duration — all without affecting the notes around it. You can take an entire recording and instantly pitch it up or down an octave — or six. You can save multiple versions of the same recording with different edits. All of that and much, much more is possible.
MIDI and digital audio each have their merits and inherent limitations. Which you use may depend upon whether you are a composer or a player or whether you want to make music like Kraftwerk or Can. A combination of the two makes for an extremely powerful creative arsenal and is the backbone of some of the most cutting-edge music. So how do you really get to experience what they are? Don't wait for the MIDI deity to bestow enlightenment onto you, do as a certain mammoth shoe manufacturer tells you: Just do it.