Confused about MIDI

[MASTON]

Let's see,

Sources, Ports, Channels, Banks, Patches ????

Anybody give me a simple practical explanation that ties everything together in a rational comprehensible whole

(I'm using an SB live at the moment, using a basic controller keyboard)

Maston

[rjt]

Hmmmm, nope to your question... a bit too complex for a simple answer. Basically, midi is computer language that says "play this note, this loud, this long" (plus a few other things that would probably confuse you right now). It will tell any sound source that understands it, to play.... hence the beauty of changing sounds etc. (the sound source is playing what midi told it to, just using different sounds) Also, since it is computer language, it is easy to manipulate.... play that note an octave higher etc.

Midi can get pretty complicated. To learn about midi, I would scope out the FAQ or support section at www.cakewalk.com That might be a place to start. There are some pretty basic midi books out there as well... Craig Anderton wrote one that gets good reviews. Your local music shop may have a pamphlet on midi. Hope this helps

Good luck!!

[rjt]

The info is a bit hard to find on the cakewebsite, so here is their discussion of midi vs audio:

http://www.cakewalk.com/Support/Lessons/MIDIvsAudio.htm

Also try:

http://home.earthlink.net/~mma/index.html


http://www.nwu.edu/musicschool/links...midiindex.html

[PenguiN]

Definately check out the references above, for a more thorough and accurate answer, but for a quick answer to your question:

Sources, Ports

One Source is like one MIDI IN on your computer, to record midi. Likewise, one Port is one MIDI OUT. The sound blaster has a couple "virtual" sources and ports ... for example, you can play directly through the sound font device, or you can play indirectly through the microsoft midi mapper (useless with the sblive, imho :P). For input source, you can grab the MIDI IN, if you were going to record from a external keyboard for example, or you could use the virtual piano if you like.

If you had multiple sound cards with MIDI support, then you'd have multiple MIDI outs and ins, and therefore ports and sources. So it's like audio ports and sources in that sense -- outs are ports and ins are sources.

Each MIDI source or port can have up to 16 channels of midi data, which brings us to:

Channels

each "channel" of midi data is an independant stream of notes. somewhat like a "track" -- though in most programs you can have multiple tracks on the same channel. They just have to share the same channel properties (these properties can change over time) -- vibrato, volume, pitch bend, for example, and bank and patch .... which brings us to:

Banks, Patches

A "patch" is an instrument. For example, piano, or drums. "Banks" are groups of Patches. For example, you might have the basic general MIDI bank as bank 0, and a cool sound font library as bank 1. patch 0 on bank 0 would be piano, and patch 0 on bank 1 would be, i don't know, some weird indian instrument or something.

One important thing to know is that channel 10 on most midi setups plays through the "percussion" patch, regardless of the patch set on its channel ... the percussion patch usually has a different drum sound per note and isn't available through the normal bank/patch selection (it's a special patch that only shows up on channel 10)


there's some other things, like Controllers, which control properties such as pitch bend and vibrato, but i'm sure you'll find more info on this stuff elsewhere.


I'm sure there's some inaccuracies here but I hope this gives you a starting point Also check out the MIDI Mania forum.

[a modified dog]

You may also want to check out:

www.harmony-central.com/MIDI/doc/tutorial.html

Cheers,
Denis

[Sash]

Every time you play a note on a keyboard it sends a message to the "brain" in that keyboard as to what note you played and how long you played it and other information such as, how hard you hit the note, did you use the sustain pedal etc. MIDI memorizes this information or more or less "records" that information and does it in relation to a clock or tempo so you can play it back in some sort of tempo or sequence. When it plays back your keys are actually playing the same part again "live" since the sequencer is sending the "brain" the same messages you sent it when you played the part to start with. Of course this is not limited to keyboards. It will work with anything MIDI, drum machines, guitar synths etc. As mentioned in other posts, since the MIDI information is data and not actually recorded it can be manipulated in all sorts of ways. When you play it back you can speed it up, slow it down, change patches, etc but the part still plays the same until you change it.

Penquin pretty much covers the definitions in his post but this is the way I try to explain it to those who have not experienced MIDI before.

[c7sus]

For a comprehensive look into MIDI protocols and arranging I would suggest Rob Young's THE MIDI FILES. Check Barnes and Noble or Amazon. Excellent book written in an easy-to-read manner. Also includes a floppy with sample MIDI files so you can listen alomg while reading the explanations of how MIDI tracks are arranged and produced.

[AlChuck]

Sash,

Just a couple of very minor clarifications on your post:

MIDI memorizes this information...

Actually MIDI is the information, or more correctly, the specification for the information and how to handle it. You'd be more accurate to say "a MIDI sequencer can memorize this information..."

What you're refering to loosely as the keyboard's "brain" is really two things, a MIDI sound engine (that understands MIDI messages it recieves and plays back notes in resposnse to them) and a MIDI sequencer. These things might be all together in a MIDI keyboard (along with the controller part -- the keys and the other buttons and knobs), or they might be separate (keyboard controller in one housing, sound engine in another, seuqncer in another), in which case MIDI interfaces on the various pieces allow you to connect them with MIDI cables so they can all communicate with each other.

As mentioned in other posts, since the MIDI information is data and not actually recorded it can be manipulated in all sorts of ways.

This is a little unclear because MIDI data is recorded by a sequencer; you even use the term "recorded" in reference to this earlier in your post. And audio is data too when it gets recorded in a computer, and can be manipulated in all sorts of ways. A MIDI sequencer records data, and the fact that the data is recorded is what makes it so it can be manipulated.

Sorry, I know I'm being nitpicky here, but I'm a former technical writer and so very sensitive to this kind of thing...

[Sash]

I stand corrected. I was just trying to put it in a way that someone who has never fooled with MIDI could understand. You are correct; I should have added the words "a MIDI sequencer" to the one statement. I guess I was referring to the MIDI process in general and may have incorrectly assumed that would be understood. And, yes a MIDI sequencer does technically record data but not in a way one would think of recording in a more traditional use of the word recording. One would also assume that our friend MASTON would think of recording, whether it be digital or analogue, as an actual recording that is to played back as recorded and then possibly some affects added, much like one would do with a reel to reel or a four track cassette recorder.

It is also true that digital audio is data. I am not a technical guru here but I would think of digital audio as a sample of a sound and MIDI data as a series of commands of start, stop, hold, etc. which although they both can be manipulated it is in entirely different ways. Once again I was trying to distinguish a difference here between what was once referred to as recording as opposed to what you can do with a MIDI file such as, changing the patch, changing tempo without a destructive edit, alter one note at a time, or quantizing.

Referring to the sound engine as a "brain" was once again an attempt to explain the process in terms a beginner could relate. Had I referred to it as a sound engine then I would have had to assume there was an understanding of what a sound engine is. Either that or try and explain that also.

I have friends I have been trying to explain MIDI to for years and some of them just cannot grasp it. Some of them cannot understand the difference between a guitar processor and a guitar synthesizer. Maybe in a technical forum such as this referring musical terms to body parts may seem a bit juvenile. MIDI is way to complicated to try and explain in a one or two paragraph post and, in hindsight, I see now that maybe I should not have even tried. I was just trying to find a way to relate the difference between what I would call conventional recording versus MIDI recording to someone who was a self proclaimed novice on the subject. It was my first day on the board and I thought I would jump in and try to help. I never was an English major so I will try and be more careful next time.

Sash
_______________

Maybe I'll just lurk from now on

[MASTON]

Thanks everybody for your valiant efforts, but especially PENGUIN who gave me exacly what I needed: I quote

Sources are INS, Ports are OUTS.

Right, OK, fantastic, the fog lifts, I get it

cheers

Maston

[AlChuck]

Hey Sash, no problem... that's part of what happens on these boards -- people write stuff, others chime in, things get tweaked... I really didn't mean for you to take it bad in any way, certainly didn't want to discourage you from posting... please post more! Your post was actually quite excellent... keep it up! Really!

[Sash]

No problem. I just have to "learn the ropes" so to speak. In reality I did not address the question directly anyway.

Sash