What Is MIDI?

Often misunderstood, but still kickin’ after 30 years – we answer the question ‘What Is MIDI?’

What Is MIDI?

It’s offered as a feature on just about every bit of modern digital music gear, but you’d be forgiven for wondering what exactly MIDI is, but if you were new to the world of music.

Even the name (Musical Instrument Digital Interface) is a bit foreboding. The truth is that MIDI is pretty straightforward, and once grasped, may well revolutionise the way you make music.

This article will provide you with a useful overview of what MIDI is, how it came into being, and how it gets used. We’ll also answer some commonly asked questions, and illuminate some common misconceptions.

What Is MIDI? - Roland Synthesizers in our Online Store

What Is MIDI

Imagine this situation: you’re about to iron your stage costume for the big gig at the weekend (the sequinned spandex trousers and tweed blazer combo, naturally), when ‘POP!’ The light bulb goes.

So you head out to the supermarket, and grab a bulb that looks like the one that has gone. On your return, you take it out of the box, and attempt to fit it. Aaaaaarrrgh!!! It’s a bayonet fitting, not a screw fitting. You fall to your knees, and scream to the sky, ‘why isn’t there just one type!!!’

Okay, maybe a bit melodramatic (*ahem!) but this is very similar to the situation faced by synthesizer players in the ‘70s, except it was much worse (so you can imagine how much screaming at the sky went on…)

Basically, synthesizers could be connected to other synthesizers and sequencers (devices that can be programmed to ‘tell’ synthesizers which notes to play), but each manufacturer had their own standards, and so could only be connected to the same brand of equipment.

What Is MIDI? - MIDI Sockets

Enter the new standard

As a result, in the early ‘80s, Sequential Circuits head Dave Smith proposed a unified standard for connecting synthesizer equipment, with a standardised ‘language’ and connections (5-pin DIN plugs). With some sizable development and help from Roland, the MIDI standard saw the light of day in 1983.

MIDI is essentially a set of standards that allows one compatible piece of equipment with another via standard 5-pin MIDI cables. So, if you press a note on a MIDI keyboard, it sends a data message about which note (or notes) were pressed, how hard they were pressed and when the notes ended. These are sent to the MIDI out port on the device.

What Is MIDI? - Simple Setup

If this is connected to the MIDI in port on another compatible keyboard or synthesizer, this can interpret this note data, and play the notes. Simple, eh?

This is one of the most straightforward uses of MIDI. These days, it is more common to use a MIDI keyboard to input a performance into a computer sequencer (such as Cubase, Reason, Logic Sonar, Pro-Tools, Ableton etc.)

In this way a composer can create complex music by layering multiple musical parts one after the other. As this is data, it can be easily edited, copied, pasted and tidied. Crucially, timing issues can be corrected and made perfect. Whether you would want to do that is a different matter entirely… 😉

MIDI can also be used in other ways. For example, MIDI can be used as a clock, to synchronise devices together. ‘Back in the day’, this could be to synchronise a MIDI sequencer with a tape machine, for example. Guitarists sometimes use MIDI clock to synchronise time-dependent effects, such as delays and modulations. You get the idea…

What is MIDI? - Cubase 7

Why do all my MIDI parts disappear when I try to bounce my track in Cubase/ Sonar/ Logic…?

This is a commonly asked question. When you bounce down within a recording package, it essentially takes all of the audio tracks and all of the audio instrument plug-ins that it is running, and converts them to (usually) a stereo, mixed track.

If you are using an external MIDI device as a sound source, these tracks are not yet audio tracks within the recording software. Confused? Okay, let me put it another way.

Think of audio tracks as being like an audio CD- an artist has performed their music, and this has been committed to a digital recording.

What is MIDI? - Steinberg Cubase

MIDI, on the other hand, is more like a piece of sheet music. It isn’t the ‘actual’ performance, but more like an accurate map that will tell any connected piece of equipment exactly how to play it.

So, when you click ‘bounce’, the computer software sees this as the equivalent of a conductor, with sheet music, and no orchestra… Instead, what you have to do is record the audio output of any external MIDI gear onto audio tracks in your computer software, then bounce it.

What Is MIDI? - Reason 7

This is also the reason that if you have a mixture of audio and MIDI tracks, and you change the tempo, your MIDI tracks will stay in time (essentially, the MIDI ‘conductor’ just waves his baton a bit faster or slower, but reads the same music) whilst the audio tracks will be rooted to the original tempo. (However, some software, such as Reason, can adjust the audio recordings automatically, too).

‘How do I convert a MIDI file to MP3?’ is also a commonly asked question. Well, if the MIDI file is being played back via external gear, you’ll need to follow the steps above, and then convert the resulting file to an MP3.

If the MIDI file is being played via a plug-in synthesizer in a software recording package, then you should be able to bounce as normal, then convert to an MP3.

Make sense? Good.

After 30 years, MIDI is still here, largely unchanged, and still at the heart of groundbreaking music.

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Joe is a contributor for the Dawsons Music blog. Specialising in product reviews and crafting content to help and inspire musicians of all musical backgrounds.