jolly roger wrote:
5. Not computer-based, or needing a computer, but if you can explain MIDI to me, maybe this is possible.
Fuck it, I'm game:
An obscure guide to MIDI.
MIDI stands for Musical Instrument Digital Interface, and is exactly what it's name implies - a means to interface (ie, connect) musical instruments digitally (don't worry about the digitally bit, it doesn't really matter). In other words, it allows instruments to talk to each other.
Imagine you have a keyboard that you like the 'feel' of, but you don't like the sounds that it produces. Imagine also that you have a second keyboard, that produces great sounds, but has a few broken keys. With MIDI, you can play a note on the first keyboard, and have the second keyboard produce the sound.
How does this work? Well, the MIDI standard defines a list of messages that can be passed from one instrument to another down the midi cable. One of the messages is 'note on', which means 'start playing a note'. Of course, the 'note on' message included information of
which note to play (known as the midi note number). It also includes information on how hard you hit the key (known as velocity), so the second instrument knows if it should play the note loudly or softly.
So as soon as you hit a key on the first keyboard, it sends a 'note on' message down the MIDI cable to the second keyboard, which knows that a 'note on' message means it should start playing a sound, so it does. And as it also knows the note number and velocity ('cos that's on the 'note on' message too), it plays the right note, in the right way.
You probably won't be too surprised to hear that there's also a 'note off' message defined in the midi standard, which the first keyboard sends as soon as you lift your finger off the key, and the second keyboard understands to mean it should stop playing that sound now. The 'note off' message includes the note number, so if you play 2 keys at the same time and then take your finger off one of them, it knows which note to stop playing.
These 'note on' and 'note off' messages only tell half the story, though. They're no good for telling the second keyboard about any changes to the mod wheel or pitch bend on the first keyboard, which it needs to know if it's going to make all the right noises. Thats OK though, because the MIDI standard also includes messages that lets the first keyboard tell the second keyboard about any changes to the pitch bend, or the mod wheel, or a whole load of other types of controllers.
There are also handy 'program change' messages you can send, so if you want the second keyboard to stop making piano sounds and start making violin sounds instead, you don't have to walk over to where it is, change the setting, then walk back to your first keyboard.
At this point, if you're still awake, you might be thinking 'but I dont have 2 keyboards, one with crap sounds and the other with broken keys, so why should I care?'. Well, there are a whole load of other uses for MIDI too. For example you can connect a keyboard to a drum machine, and then play the drums by hitting different keys on your keyboard. Lots of people do this to get a human feel out of their drum machines.
Also, you can connect a keyboard to a sequencer. A sequencer isn't another instrument, but it's more like the MIDI equivalent of a tape recorder. It can record the midi messages you send to it, and play them back to you. This saves you having to write down on paper the tune you've just come up with, if you want to be sure you don't forget it. Even better, once you've recorded the MIDI data in the sequencer, you can edit it. So if your timings as bad as mine, you can get the sequencer to fix it for you. In fact, once you know how to use your sequencer, you can just program the details into it directly without having to play a note on the keyboard at all. This means you can write stuff that's way beyond your ability to play, and have your sequencer play it for you. These days my keyboard skills are so rusty I can't play most of the stuff I've written for songfight. Thanks to MIDI, I don't have to :)
Even better, you can connect a keyboard or sequencer to two keyboards and play both of them at the same time. You could have one of them playing a bassline with a real beefy bass sound, and the other playing chords with a soft choir-type sound over the top (for example). Hell, throw in a drum machine and you've almost got a full backing track for a song going on right there. Of course, if you have both instruments playing both the bass and harmony parts at the same time it'll sound awful, so you'll need a way to make the bass synth know to only play the bass notes, and the other one to only play the harmony. Luckily, the MIDI standard includes a way of doing that, called midi 'channels'.
A MIDI channel is much the same sort of idea as a TV or radio channel. Your TV can receive a number of different channels from your ariel, but only displays the one you tell it to. Likewaise, a synth can receive a number of MIDI channels from the MIDI cable, but it only responds to the one you've told it to. So you could have the synth that's playing bass listening to channel 1, and the choir-playing synth listening to channel 2. Then you'd tell your sequencer to send the bass part on channel 1 and the choir part on channel 2 and you'd be set. Or if you're playing the part live on a keyboard, most decent keyboards will let you program them to 'split' the keyboard, so that notes played on one half of it are sent down one midi channel and notes played on the other are sent on a different channel. There are 16 different MIDI channels, which you can use however you want, although it's kind of a convention that drum sounds are sent down channel 10, so that's often the default for drum sounds.
The really cool thing here is that even if you want to use all 16 channels to play a part, you don't need to buy 16 different keyboards! Most decent keyboards are 'multi-timbral', which means they can play more than one different sound (timbre) at the same time. So you can tell the one keyboard to play (for example) bass notes when it receives note on messages on channel 1, choir notes on channel 2, piano notes on channel 4, an organ on channel 5, a saxaphone on channel 6, and drums on channel 10. Just connect that one keyboard to a sequencer with the parts programmed in, and that's it, that's your song right there, you just need to sing the vocals and record it.
A word of warning tho': not all keyboards can use all 16 channels at the same time. A common limit is '8-part' multitimbral, which means it can only play 8 different sounds at a time, and some keyboards might have other limits like 12-part or whatever. There are also other limits like polyphony on synths but they're not really anything to do with MIDI so I'm skipping them.
If you play guitar, and have a decent FX unit, it'll probably have a MIDI input to allow you to control some if it's settings from a sequencer or keyboard. Or there are other sources of MIDI data, like a MIDI guitar or MIDI drum pads, that you can use if you prefer those to keyboards (although last I tried one, MIDI guitars weren't very reliable).
Probably the most useful thing you can connect a keyboard to using MIDI is a computer. The way a computer handles MIDI messages that it receives, or decides what MIDI messages to send, depends on what program is running on it. You can have sequencer programs that do the same thing as the sequencer device I mentioned earlier. Computer-based sequencers tend to be a lot easier to use 'cos you've got a full screen, keyboard and mouse to work with, and you can save your songs to hard drive. You can also run virtual instruments, so your computer acts like it was a synth, or a drum machine, or a sampler, or even a guitarist!
If you've made it all the way through this and are thinking it all sounds kinda neat, you're gonna fucking LOVE it when you start to understand DAWs and VSTs. It'll rock your world.