Musical Instrument Digital Interface, better known as MIDI, is a language by which computers, virtual instruments, and hardware samplers/synthesizers can communicate.
This MIDI FAQ post originally appeared on Cakewalk’s blog. Reprinted with permission.
MIDI, or Musical Instrument Digital Interface, is a language by which computers, virtual instruments, and hardware samplers/synthesizers can communicate. It’s a way to give instructions to music production software like SONAR X3 to play, control, and program your own tunes. Even touchscreen tablets have the ability to generate and accept MIDI information.
MIDI is a great way to work with music and has powerful capabilities that appeal to users of all levels. There are a lot of unfamiliar terms and concepts in the MIDI world, so let’s take a look at a few questions that I typically hear from first time users in this MIDI FAQ.
What is MIDI? Can I hear it?
MIDI by itself is data – it is not a sound perceptible by the human ear. It is a universally accepted standard for communicating information about a musical performance. It encompasses both hardware and software components, and though it could be used for sending information about many other things, such as the control of lighting in a theater, or even to control your coffee maker, it was developed to transmit instructions about music. Like a musical score, on which notes and other symbols are placed, MIDI data carries instructions that allow MIDI-capable instruments to produce sound.
Where did MIDI come from?
MIDI was born in the early 1980s when electronic instrument makers, primarily in the US and Japan, recognized that their instruments must be able to talk to one another. After the details were worked out, manufacturers soon began to include electronic circuitry in their equipment that allowed them to understand MIDI. Before long, nearly every instrument manufacturer in the world had adopted the standard. There have been refinements and modifications to MIDI along the way, but even the earliest MIDI instruments are still compatible enough to be used today. MIDI has dramatically changed the way music is created, performed, and recorded.
How Does MIDI Work?
A MIDI transmission consists of a series of signals called bits. These represent binary digits that pass through a MIDI cable or virtual MIDI port. This data communicates with software programs on synthesizers, virtual instruments, computers, and digital audio workstations. When the data reaches it’s destination, the software interprets it as a series of instructions that usually results in the production of a sound.
How do I create MIDI and program sequences?
There are ultimately two ways to create MIDI. The first involves performing your music on a controller that is connected to a computer running a virtual instrument (often within a DAW). This could be drums, keyboard, strings, or even sound effects. The DAW will record the data outputted from the controller much like it would capture audio from a guitar or microphone. After that, you can edit and modify the data utilizing the tools found inside the DAW.
The second involves manually entering data into various MIDI-compatible views within a DAW. SONAR has a few different views that give users tons of options when working with MIDI.
Track/Main view. This is probably the easiest and most basic method for constructing MIDI sequences. Users can record their performances into this view or drag other previously recorded information in from the Media Browser. Here you can cut and paste sections, loop sections, or comp together different takes of the same performance for one overall flawless take.
Piano Roll view. Piano Roll views generally display bars and beats across the top and a keyboard with associated notes along the left side. Using a cursor and a series of tools, users can manually construct their MIDI sequences from the ground up and adjust several types of controllers and MIDI messages. Here users can make major alterations to performances they’ve made and quantize their out-of-time sequences. The Piano Roll View is probably the most popular for constructing sequences.
Staff/Notation View. Some DAWs allow for MIDI sequences to open up within a notation editor. Translating this information to this kind of a view is powerful for songwriters, composers, and people who need their music printed for session players and conductors.
Step Sequencer. Step Sequencers are based off of sequencer modules that have existed in a hardware format for many years. Step Sequencers have cells that run from left to right. Like the Piano Roll View, each row of steps are associated with a single note of an assigned synth or drum machine. Typically these steps represent subdivisions of measures like 16th notes and 8th notes. The advantage is that there is less work involved in constructing a sequence in comparison to views like the Piano Roll, where nothing is loop based and there are way more options for editing.
Matrix/Loop Player. DAWs like SONAR X3 have other useful MIDI tools to construct performances on the fly. The Matrix View allows users to drag and drop MIDI loops into cells that are assigned to different instruments. In addition, users can map the cells to MIDI controls simply by right clicking and “learning” the cell to a MIDI controller key.
What’s the difference between a MIDI controller, hardware synthesizer, and a virtual instrument?
MIDI is a lightweight protocol that can be used in just about any paradigm these days. The problem is that things can become confusing if you’re not hip to the nomenclature used in today’s pro audio websites and magazines. Some websites outline specifications well, but others can be vague. Here are some differences:
MIDI Controller. MIDI Controllers do not generate any sound, even though some of them look like pianos. MIDI controllers are used mainly to send and receive data from any instrument or software that supports MIDI. This includes sending data to computers that host virtual instruments.
Not all MIDI Controllers look like keyboards; there are MIDI controllers for just about every type of instrument. There are MIDI wind controllers, guitars, vibraphones, pedal board footswitches, drums, and new instruments that are in their own category.
Hardware Synthesizer. Synthesizers generate sound and use MIDI data to trigger musical notes and embellishments. Some synthesizers come with a keyboard as a way of using the synth in a performance environment. Others are just desktop sound modules that do not have a keyboard, so you must send data to the sound module through your DAW or external MIDI Controller.
Virtual Instrument. A virtual instrument is a plug-in that exists only in the digital domain. There are plug-ins that generate all different kinds of sounds. Since nearly all music production went digital in the early 2000’s, the market for this type of software has increased in popularity. Synthesizers like Z3TA+ 2, Lounge Lizard, and Addictive Drums can be dropped into a DAW and almost immediately create jaw-dropping sounds.
What’s the difference between a MIDI Interface and an Audio Interface?
MIDI Interface. Before the Pro Audio world opened up to a more consumer-based market, users had dedicated MIDI interfaces that would allow them to sync and communicate to multiple MIDI devices. As you could have guessed, MIDI interfaces do not pass any sound, only data.
Audio Interface. Audio interfaces pass audio – that isn’t hard to understand. What can become confusing is when an audio interface also has MIDI In, Through, and Out ports. These types of audio interfaces are all-in-one solutions for everything a user might need in a personal home studio. Not all audio interfaces come with MIDI ports, so make sure to check out the specifications before making any purchases.
What are MIDI messages and why are they important?
MIDI messages are the language that MIDI uses to send detailed information to a device or software about the data it’s sending. These messages are divided into two categories: Channel messages and System messages.
Channel messages consist of the following information:
- Notes that should be heard
- When to start a note
- When to end a note
- How loud a note should be
- What type of sound (trumpet, drum, flute) should play the notes
System messages consist of information pertaining to a song, global synchronization, bulk dumps, saved parameters, and other non-specific data.
Can I convert audio to MIDI and MIDI to audio?
Digital music technology has come a long way since the early ’80s, and now converting audio to MIDI and back is pretty easy to do. For example, within SONAR X3 you can drag an audio clip directly onto a MIDI track and the integrated Audio Random Access (ARA) Technology will convert it on the spot. Celemony has developed this technology and Direct Note Access (DNA) which can separate polyphonic audio into polyphonic MIDI data.
On the flip side, SONAR can convert MIDI data to audio by means of freezing or bouncing. Freezing MIDI will replace the sequence with audio on the actual track. This is useful in the event that your project is passed to a computer that does not have the same instruments as yours.
Bouncing sends a sub-mix of the performance of the MIDI sequence to another track and keeps the MIDI sequence intact and unharmed. Bouncing can also sub-mix multiple tracks into one stereo audio file, so be sure to only bounce the single MIDI track. Both methods can convert MIDI to audio, it’s just a matter of preference.
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