Midi - a beginners guide

Midi increasingly pervades the life of the modern musician. Its almost unavoidable. At a large folk festival recently I was amazed to see that at least a third of the bands had as much midi going on on stage as in your average medium sized studio. If you go to a professional gig or into a recording studio, you're likely to be surrounded by midi.

Midi is basically THE way that instruments and other pieces of musical equipment can communicate with each other.

So for example using midi, the foot switch you use to switch on your lead sound if you're a guitarist, can also tell your delay unit to change from chorus to echo. You could even change the keyboardists sound (heaven forbid). Or more usefully you could start, stop, record on your computer sequencer.

Basically if your equipment is midi compatible (and increasingly everything is), you can use midi to control just about anything.

Imagine having one footswitch that can tell five pieces of equipment to do five different things with once click - that's one of the main things midi is used for.

Even mixing desks are starting to use midi. So that for example a computer sequencer running alongside a mix in the studio, can run the mixing desk. So you can have an automated mix, the computer telling the mixer when to bring up the backing vocals, when to add reverb to the keyboard, when to cut out that duff note you played etc... No more mixes with five people and stop watches sweating over a mixing desk for five hours for one song. You just program the mix on the computer, one bit at a time, then run the tape and the computer does it for you without the stress!

But there is another area that midi is used for. Its not just used a a way of one piece of equipment controlling another.

Midi is also THE way that an instrument can communicate with another instrument. The most basic example is the way keyboard players have one keyboard but its connected to several synths (which may just appear as boxes in a rack unit). So the keyboard player may have a piano module, a vintage synth module, an orchestral module, a sampler - all in a rack unit. But they'll play all these things with the one keyboard, switching from one sound to the other or combining them all from the one keyboard.

So in this case its not just the switching that is going on through midi, but the notes are being sent too. This is in fact one of the primary uses of midi - the sending of musical notes from one instrument to another.

Its all actually very simple in practice. You simply plug one end of a standard midi lead into a keyboard and the other into a sampler or another synth. Line up the midi channels on both and there you are - you play the keyboard and the sampler plays the same thing.

Taking a closer look at exactly midi transmits we see it is capable of communicating a lot of different things seeming simultaneously.

Amongst the things midi is most commonly used to transmit are:

The note you play ie: A#, Db etc... (note on message)

How long you hold the note for (note off message)

How loud you play the note or how hard you hit it (velocity)

Then there are other messages which are called controllers. Yep you guessed it, they're used to control things:

Pitch bend, bent notes, vibrato etc... (pitch bend)

Sustain pedal for keyboards

Pitch wheel for keyboards

Modulation for keyboards

Main volume like a master volume control

In fact there are a host of other things midi can control, too many to list here.

Apart from these controller messages and the actual music note and pitch volume etc.., midi sends one other very important piece of information.

Patch Changes. Midi is often used to send patch changes. So for example if on your synth patch number 57 is trumpet, your computer sequencers could send a midi message that not only sends the right notes to your synth, but also makes sure it plays a trumpet sound by sending a patch change of 57.

Another application of sending patch change is where you want your guitar multi-effects floor pedal to also control something else. For example, you might have an external reverb or delay unit that you want to use in conjunction with your normal multi-effects pedal. So you could uses your floor multi-effects pedal to change the patches (sounds) on your delay unit. So if you have a massive space stadium flanged reverb setting for your lead break (heaven forbid), you can get your floor pedal (if its got midi) to send a patch change message to switch your delay to super space stadium or what ever.

To finish off I'll just briefly introduce you to the last type of message midi can send. That is, try not to be put off by the name, a 'system exclusive message'. A system exclusive message is a message that carries information unique to a particular piece of equipment. This can be used for various things, but the most common use is the following: you can use system exclusive messages to store all the settings on your synth or effects unit. So if you've spent months programming sounds into your synth or effects unit, you can system exclusive to send all this information to a computer, where it can be stored (as a midi file) on disk. So if you accidentally erase one of your favourite sounds, or a unit has to go in for repair (where all sounds may be erased), you can just load them back in from your computer. The process of saving sounds (settings) onto a computer or sequencer is called 'dumping'.

So here I have covered the basic principals behind midi, what it can do and what its used for. If you can grasp the basic principles behind it, you'll probably find that you'll learn all the specifics, by just working with your own midi set up in actual practical situations. Decide what you'd like midi to do for you, identify the basic midi function that you'll need to use ie: patch change, music notes messages, controller, system exclusive. Then use your manual to work out the specifics for each piece of equipment involved. If you get confused, about getting a particular midi function to work, give the manufacturer a ring and ask for tech support. Tech support are usually very helpful, and will talk you through what to do. But be fair to them, you should make a real attempt to use the manual first!

Good midi-ing