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MIDI BasicsWhat it is, how it works, why it's important
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MIDI 101 1. Understand MIDI data 2. How to setup a keyboard and sequencer 3. Configuring Ports, Channels, Tracks and Instruments |
Ok, professional mixologists, filter-heads, LFO-freakoids, Vintage synth-masters, and advanced sample rippers please click here to go back to the end of the article, where I will let you back in. And don't smirk at these new dudes on the way out! This article is for the newbie who wants to get going using MIDI and audio and making their own music. This is the most basic of the basics. Its for the person who knows nothing at all about MIDI and audio technology but wants to learn really fast and learn everything you need to know for success.
So I should only have Newbies here now. Cool. Don't worry about all those "pro" elitists, they were here once themselves (and probably not long ago). Lucky for you, the Tweak is your teacher. Pay attention 'cause there is a test at the end. Let the TweakMeister get you up to speed in 10 minutes. In this article we talk about MIDI, then next we'll get into AUDIO and after that we'll ties them together and discuss the Basic Recording Studio.
Let me
say it now. Those that succeed as home electronic musicians understand
MIDI. You can try to get by without it, but it will dog you at every
turn. Don't think the MIDI is only something that keyboard players need to
know. Today, MIDI controller data is used to automate a variety of studio
gear, including the hardware and software mixing consoles we use. Read the
next paragraphs several times, slowly.
MIDI,
the Musical Instrument Digital Interface is a protocol
developed in 1983 by major synthesizer manufacturers to allow one synth to play
another remotely. They tried to figure out a way they could make a second synthesizer
play by sending it control data from the first. They figured it out, and more!
The developers quickly found out a computer could record and playback 16
channels of this data and it revolutionized the way music is produced. Then they
discovered with the right hardware you can have several of these 16 channel bundles
(or ports) all running at once. The implications were profound.
Now one person could compose multi-part music all by themselves.
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IMPORTANT: MIDI works by sending NOTE ON and NOTE OFF events down a midi cable as well as timing information and controller (knobs, wheels, and sliders) information. Read that again, OK? MIDI works by sending NOTE ON and NOTE OFF events down a midi cable as well as timing information and controller (knobs, wheels, and sliders) information. MIDI does not send sound, or audio down the MIDI cable. |
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---->Understand that MIDI is NOT an audio signal<----- |
The sound (or audio waveform) of the keyboard or module does not go down the MIDI cable, only these computer encoded "events" do. What is an "event?" It's all just numbers, man. But not the large blocks of numbers that make up an audio waveform. MIDI events are just ones and zeros that say when you pressed down which key (a note ON event), how hard you pressed it (velocity number), when you let the key up (a note OFF event), pressed the next key, moved a knob (controller data), changed a program (program change command). That is the basic point you have to fully understand. The cool thing is that all this MIDI data, once recorded, is fully, totally, completely editable, malleable, changeable, transformable, re-assignable, erasable, replaceable and it all happens on the edit screens of your sequencer.
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This is MIDI DataNotice that in this screen "position" is the time stamp, "num" is the midi note on command, "val" is the velocity value and length/info is the length in ticks. 240 has the duration of an eighth note |
MIDI
Sequencers (i.e., Sonar, Logic, Cubase) work by recording
these NOTE ON/OFF events along a timing grid that can be played back at any tempo.
When you press Play on a sequencer, it simply sends the data back to the synth,
which turns on the notes and plays it just like a player piano. Get it? Because
the Synth receives the exact same events that it sent when you played
the track, it sounds exactly the same. If it doesn't sound like you want
you can edit it on the screen. That is how MIDI data is converted to sound.
Once the synth is playing back a midi track, now you can record that track as an
audio track, assuming you have a hardware MIDI synth, by connecting the analog
outputs of the synth to the soundcard line inputs and pressing record.
Now you have an audio track. Makes sense so far? Cool.
If not, read that paragraph again. It's critical.
MIDI devices (i.e., keyboards, hardware sound modules and control surfaces) typically have 16 channels they can send and receive on. Much like your TV, you can have a different program on each channel. The only difference is that MIDI can play all 16 channels at the same time. These channels correspond to tracks in your sequencer. On each track, you can assign a different instrument. A typical starter MIDI keyboard may have hundreds of instruments to choose from. You record each track while the previous tracks play back. Because MIDI has 16 channels, you can have 16 instruments playing together, like a 16 piece band, if you want, that is totally of your own design.
Core Concept: MIDI data can be recorded as sequences of notes onto different tracks which correspond to channels
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Why is MIDI confusing? Because the terms change depending on your vantage
point. From the vantage point of the computer, the MIDI out goes to a device,
like a keyboard. The MIDI in comes from a device, like a keyboard or drum
controller.
From the standpoint of the keyboard, the MIDI
out goes to a computer or another device.
When you play notes on the keyboard, data goes out the MIDI out
of the keyboard. It does not go through the MIDI Thru.
| Keyboard MIDI OUT-------->Computer MIDI
IN Computer MIDI OUT-------->Keyboard MIDI IN Keyboard MIDI Thru------->exact copy of the data coming in the keyboard MIDI in |
The Computer MIDI out passes through the Keyboard's
MIDI IN and then to the Thru. The data coming
out the keyboard MIDI thru jack is exactly the same as that which arrived at the
MIDI in from the computer. However, and here it gets tricky, the data going
out the MIDI out of the keyboard does NOT go through the MIDI thru.
Only data coming into the keyboard goes out the thru. Got
it? If you understand that simple point you will be ahead of most people.
Whew!
USB MIDI i/o is simpler to deal with from a conceptual point of view. Data flows in both directions down a single cable.
There are 16 channels for every
hardware MIDI IN and OUT PORT (MIDI i/o) on your computer. Your computer's
soundcard may have MIDI i/o, and if not you can buy a MIDI interface to add MIDI
i/o. First lets look at all the ways you can get MIDI data to your computer.
MIDI IN Ports:
There are 4 basic ways
to bring MIDI data into a computer. You need to have at least one of them
to connect a keyboard or controller.
1. Some keyboards (not all!) come with built-in USB MIDI interfaces. For these you just connect the USB cable to the computer and install a driver (if required). The port will show up in your software.
Example of a keyboard controller with USB MIDI. You don't need a MIDI interface if you connect via USB. See more controllers
2. Many soundcards and audio interfaces may have a built-in MIDI interface. The M-Audio 2496, Delta 1010, Emu 1820M, MOTU 828mk2, Tascam FW1884 (and FW 1082) are examples of devices that have built-in MIDI ports. Here you connect your gear to the standard MIDI jacks on the interface.
The Emu 0404 is a USB 2.0 audio interface that has a MIDI in and out port on the back. See my chart that shows which audio interfaces offer MIDI ports
3. In this case that you don't have a built-in hardware
MIDI interface on your soundcard or a USB MIDI interface on your keyboard (or controller),
you have to purchase a separate MIDI Interface. They are not expensive
and are generally more reliable than joystick ports. Usually the interface connects
by USB to the computer and you connect your MIDI hardware via the standard MIDI
jacks on the interface.
Example of a separate USB MIDI interface. See more USB MIDI Interfaces
4. On SoundBlaster-type cards, the JOYSTICK port can be adapted to be a MIDI interface. In the case of the SoundBlaster, you need a cable that connects to it on one end and gives you 2 MIDI connectors on the other end, a MIDI IN and OUT. The Soundblaster Live is an example of a soundcard that has a joystick port. These tend to be the least reliable MIDI ports in my opinion.
M-Audio Sound Card MIDI Adapter Cable (4 ft.)
Turn any Sound Blaster Pro Compatible Soundcard into a Powerful MIDI Interface
If you have a number of midi input devices like keyboards, drum machines, controllers and control surfaces they each need a way to connect to the computer. You can have a USB keyboard, a drum machine connected through a MIDI port and a control surface connected by a 2nd midi port and all 3 will input data simultaneously to the track you are recording. Methods can be mixed an matched. You computer will see and use all MIDI inputs connected, whether they are on your soundcard or interface, are connected through your USB hub, or are coming from a separate MIDI interface.
To send control events, (i.e., "notes") to your sequencer any keyboard with a MIDI out will work, even if it sounds like crap. Remember, you only need it to trigger the NOTE ON NOTE OFF event to the sequencer, which will send them to your available synths, which will send the sound to the speakers. Get it? Though the playing happened at the keyboard, the sound can be triggered at any MIDI sound source, whether they exist in hardware or software. You can even use an old CASIO with the speakers ripped out as long as it has a MIDI out.
To Review: External MIDI IN ports bring MIDI data from outside to inside the computer, where it can be recorded, and sent back out the MIDI OUT port to the external device upon playback.
Now lets look at how MIDI data leaves the sequencer
application in the computer and goes to different devices that make sound, both
inside and outside the computer.
External Ports: The recorded
data goes out of the sequencer to the MIDI out port which is connected to the
MIDI in port on your hardware instruments. The obvious example here is the computer
that sends MIDI data back to a hardware synthesizer. The instrument receives
the data and plays the sound.
Virtual Ports:
Internal MIDI ports direct data to sound sources inside your computer.
Your sequencer can create a virtual MIDI OUT port for every software
synthesizer on your system. Up to 16 MIDI channels can be available for
this virtual port, though a typical softsynth may not use them all. An
internal virtual MIDI port may also go to a MIDI synthesizer that is built into
your soundcard (Soundblaster cards have these) or to a small software synth installed in your operating system, such as
the Microsoft GS Wavetable SW Synth, which is part of Windows XP.
In this example, from Sonar 4, I have 2 hardware external MIDI ports (the E-DSP entries, which were created when I installed my EMU 1820m audio interface) and 3 internal virtual ports, the MS GS Wavetable SW synth, Pro 53, and Cakewalk TTS. (the TTS was created when I installed Sonar, and I bought the Pro 53 as an add-on) I can route the track to any channel on any port.
The External MIDI port will show up in your sequencer application after you install the drivers. When you use a software synth, a virtual MIDI port is created and will show up in your sequencer application as soon as the soft synth is "instantiated" (that's just a buzzword for "initialized." or started.)
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Figure 1: Basic MIDI setup using a 1 port USB MIDI interface with standard MIDI jacks
Keyboard MIDI OUT--------->MIDI Interface IN (required!) MIDI Interface USB OUT---->Computer USB IN (required!) MIDI Interface OUT--------->Keyboard MIDI IN (if you are only using your software synths this connection is not required. If you want the computer to play the sounds on your keyboard, or if you want to connect a 2nd module it is required) Keyboard MIDI THRU ------->Keyboard or Module #2 MIDI IN (optional) Keyboard or Module #2 MIDI THRU -----> Keyboard or Module #3 MIDI IN (optional) |
Connecting Keyboards and Modules: The sequencer MIDI out port can connect back to your keyboard's MIDI IN and play up to 16 channels of voices if the keyboard is "multi-timbral" (meaning it can sound many instruments at once). Some synths are not. Old keyboards, like a DX7, only respond to 1 channel unless you hot rod it. You can usually set the keyboard to respond to only one channel if you want or to only channels 1,2,3,7,8, for example, or to all 16. Turning off channels allows you to daisy chain more keyboards or modules by cabling up the 2nd machine from the MIDI THRU on the 1st machine (which is an exact copy of the data coming in the MIDI IN) to the MIDI IN of the second machine. It is possible to have one MIDI port to control 16 different keyboards if you want it too! Usually, if your rig gets this large you will buy a MIDI interface with 4 ports so you can play all 16 channels of your Triton on one port. On a second port you might have with 10 channels from your Proteus 2000, a couple for your Electribe, one for each of your 3 effects box, and the last for your drum machine. Port 3 may use all 16 channels for a control surface and Port 4 might use all 16 more for a digital mixer...ooops sorry, I forgot we are just getting started.
Once you have configured your MIDI system (see Figure 1 above) you should note how the channels inside the sequencer can be routed to different sources both inside and outside the computer (see Figure 2 below). On every MIDI track in the sequencer, you specify where it goes. The more gear you have, the more places you can send the data. You could take the bassline you just recorded and route it to a virtual drum machine, edit the notes so they all trigger kick drums, for example. Or make a Marcato String cadence on your Triton, copy the data to another track, assign the track to Module 2 and have the same data play an ambient synth pad. The two together sound like a very dreamy string section. Get the idea? The flexibility of routing MIDI data allows for tremendous creative expression. Below you see a MIDI system with 3 hardware devices and 3 software devices. You can achieve that with just one hardware MIDI port.
Figure 2: Flow from Sequencer MIDI OUTs to Synths
MIDI INs |
 Advanced
MIDI In/Out/Thru Brain-Teasers
Lets say you have 2 machines daisy-chained
on the same MIDI OUT port. That is, the keyboard MIDI IN is connected
to the computer MIDI out and MIDI sound module #1 MIDI IN is connected
to the Keyboard's MIDI THRU(see Figure 1 again for an example
of daisy chaining). Now lets look at figure 2 again.
If you are sending a track down channel 7 from the sequencer and have
the Keyboard turned OFF on channel 7, What will happen? The keyboard will ignore the data but will still pass it to the next module. Why is that? Because all of the data coming in to the keyboard is also going out the MIDI THRU, MIDI sound module #1 will play the track. So you ask, what happens if channel 7 is set to ON for both devices? Bingo dude! You got it, they both play. Now if each synth was on a different PORT, would both synths make a sound. Nope! Why not? Each port is totally discrete, that is separate. The data on Port A does not go down Port B. To recap, remember, each port has 16 channels of its own. The Port is the parent; the channel is the child. So, lets jump ahead, if you get
a midi interface that has 8 ports, how many channels do you have?
Yes, you math genius, 128. Does that mean you can connect 128
keyboards to ONE 8 port midi interface. YES!
But don't call me to wire it ok? Most people put each synth on
it's own dedicated port so they don't have to turn channels on and off
all the time.
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Most basic synths follow a specification called General MIDI or GM. This protocol specifies what programs (instruments) are available for the 16 channels. Drums are typically on channel 10. You can assign the rest the way you want. The basic GM set consists of 128 programs which always have the same program number. Piano is always program 1. 34 is always Picked Bass, 67 is always Baritone Sax. Ok, Here's the Chart of GM sounds. Because there is this common reference, any file you make with GM can be played on any computer or synth that follows the GM spec. That's what a MIDIFILE is. Its a sequence made up of tracks filled with timing information and NOTE ON/OFF information.
A "MIDI"
or Midifile has no audio data again. It only has note and controller and time
data. But because manufacturers follow this standard spec, it sounds the same,
or similar, on different soundcards. Its possible to do a great composition
with GM, but the limits are in the relatively small palette of 128 sounds. But its
an excellent way to get started. After a while you might want better, more
varied, or more specific sounds--that's when you know its time to move on to standalone
modules that give you hundreds, often thousands of instruments, or focus on specific
genre's like dance sounds, orchestral, hip hop, world fusion, R&B, etc.
As we just saw, the GM bank has 128 instruments, or presets. If you get a bigger better, synth, you get more banks. My nearly maxed out Triton Rack for example has 16 banks of 128 instruments, or 2,048 instruments to choose from. My Pro 53 softsynth has 512 presets in 4 banks. Thanks to the Program change command I can select any instrument I want with the mouse from my sequencer. Now imagine the full MIDI rig with several softsynths, virtual drum machines and a good hardware synth. Thousands of sounds, any type of drum kit you want, all freely assignable to your MIDI tracks. I have been using a large MIDI rig for a long time and have never exhausted the possibilities.
The program change commands are not limited to synths, but can also be used to switch programs on effects boxes (such as reverb, delay, harmonizers, etc). Many studio devices can be switched internally by program changes. There are MIDI features on automated mixers, amp modelers, patchbays, even some compressors.
 Note: By selecting the bank number and preset on the Pro 53, I have access to 512 sounds. Some hardware synths like the Fantom can hold thousands of sounds and in some of my soft samplers, for example, I have over 10,000 sounds. |
MIDI data is also used to control software mixers in the sequencer and is sometimes used to control hardware digital mixers as well. Through use of continuous controller commands, or CCs, MIDI data can automate volume, position, effects sends, and even the parameters of hardware and software synthesizers. Using MIDI CCs you can turn the dials on your synths and record the knob movement. When you overdub 5 times it is like having 5 hands controlling the knobs on your synth. If you "almost" had the tweak perfect, you can go in the editors and edit the CCs with exacting detail.
Because MIDI data is compact in size its easy
for a computer to manipulate it. You can easily have 50 tracks of midi
instruments running in a song if you have enough ports and channels. In
the sequencer, midi tracks can be copied, looped, transposed, doubled, stretched
and edited to fine detail. You hit a wrong note? No problem, edit
it to the proper value. You have a great idea but your timing is off?
No problem. Simply apply a quantize template and your notes will lock
to a grid or a groove. You don't have to be a good keyboard player to
make excellent sounding compositions. Simply correct the tracks till they
sing for you. In the sequencer, every element of the MIDI stream can
be modified. You can call up a track and edit it on a musical stave
like the "old" composers used to or on hi-tech grids, or in a list of events.
OK, all you homeboys who think that MIDI is "old" and not as cool as hot
audio loops and beats take note: Most commercial loops are built with
MIDI data controlling digital samplers. The true and authentic
tweakhead and groovemaster either uses MIDI to make their loops or has such
impeccable timing they just record it cold. Of course you could buy
and use store-bought loops, but you'd be restricted to using other people's
sounds and stuff. Get a sampler, makes some noises, edit to perfection
with MIDI, grooving, quantizing, transposing and you are 100% originally
you! Record the output and edit the sample and you just made your own audio
loop. That's how the true tweaks do it.
Also consider sound effects
for film, TV commercials, radio spots. With MIDI you can stack of
sounds, samples, and instruments to make huge effects. Using MIDI is
one method for those who make sounds and music for a living.
Ok, lets let the pros back in but never let these guys intimidate though, OK?
Don't think for a minute that MIDI is not a serious musical tool. Nearly all TV/film scores today make use of MIDI. Many top 40 songs are made with sequencers in home studios and converted to professional audio using the same process we just talked about. MIDI is the core building block on which to build a totally original musical masterpiece on a computer. When you have it working properly, with a good synth, your musical output is truly only limited by your musical imagination. As we go deeper into understanding the modern recording studio, I'll show you more on how MIDI data is used to control your virtual mixer. For now, think of it as a data pathway for connecting and controlling many studio devices.
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Want to talk about
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Cool Quote: "Truly fertile Music, the only kind that will move us, that we shall truly appreciate, will be a Music conducive to Dream, which banishes all reason and analysis. One must not wish first to understand and then to feel. Art does not tolerate Reason."
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