Welcome to this new series of tutorials where I will pick individual topics to demonstrate basic concepts, functionalities, and workflows in Pro Tools. It is not a step-by step-instruction to learn Pro Tools, instead, by focusing on important aspects, I hope to provide a better understanding on how to use Pro Tools. The discussion and the screenshots are based on the free version "Pro Tools | First", but they also apply to the standard or HD version of Pro Tools. This makes these articles suitable for new Pro Tools users who are starting to learn the app, as well as for existing users who want to improve their understanding and knowledge about Pro Tools.

Audio Clips Vs MIDI Clips

In this tutorial "Audio Clips vs. MIDI Clips" you will learn the fundamental differences between Audio Clips and MIDI Clips. Although they share many similarities and tasks when dealing with them in Pro Tools, not being aware of their differences can result in surprises and major headaches when working in Pro Tools.

Audio Signal - MIDI Signal

Before talking about the different Clips, we have to be aware that there are two different types of signals in music production. Let me demonstrate that in the following diagram:

When working in Pro Tools, or pretty much any DAW, you are dealing with two types of signals, Audio signals ➊ and MIDI signals ➋. You can record ➌ those signals, which then show up as Clips ➍ in the Edit Window, and later, play back ➎ those Clips by sending the recorded signals through Channel Strips ➏ in the Mix Window in oder to apply all the magic to your production.

At any time when working in Pro Tool, you have to be aware of what type of signal you are applying the current task to. The actual procedure (edits, tools, commands, controls, etc.) might be the same or similar for audio signals and MIDI signals, but the results (and consequences) could be quite different.

Two Stages

You can see in the previous diagram that I separate the production into two stages, the Storage ➐ part, where all the signals are recorded and edited, and the Processing ➑ part, where all the signals are sent through various components in the mixer to "alter" them.

• Storage ➐ (Clips): The MIDI Signals are recorded/stored in MIDI Clips and the Audio Signals are recorded/stored in Audio Clips. That's how it looks like. However, as we will see in this tutorial, that assumption is not entirely correct.
• Processing ➑ (Signal Flow): The Audio Signals and the MIDI Signals are both "running through" the same mixer in Pro Tools. However, you have to be aware of which components on a Channel Strip affect an Audio Signal and which one affect a MIDI Signal. I will go into more details about that in another tutorial.

About Musicians and DJs

Now let's look at how those audio signals and MIDI signals relate to Audio Clips and MIDI Clips. I use the following analogy to show their main difference:

Usually, a DAW has a Tracks area, often called the Arrange Window (Pro Tools calls it the "Edit Window"). Think of this as your band. Now assume you have five tracks in Pro Tools and these five tracks represent your "Band", a group of five professional musicians. For example, a guitar player, a bass player, a keyboard player, a drummer, and yes, a DJ (it seems that every band nowadays has to have a DJ).

When you want that band to perform your song, you hand everybody their sheet music, the instructions of what to play. The music is written as an instruction in the form of musical notation. Luckily, everybody in your band knows how to read the musical notation (even the drummer) and they "translate" the written notation into music on their instrument by playing what is written on the sheet music. The exception is the DJ. You can't hand the DJ a written score. Instead, he needs the music in pre-recorded form such as CDs, mp3 files, or vinyl records.

MIDI Clips

Here is how the analogy relates to MIDI Clips:

• In your band, the music ➊ for your musicians is written as musical instructions, the sheet music ➋. 
• In Pro Tool, those musical instructions are the MIDI Clips ➌ (that data is then sent to your MIDI sound modules, your virtual musician).

Audio Clips

Here is how the analogy relates to Audio Clips:

• In your band, the music ➍ for the DJ is represented by an audio recording, the CDs ➎.
• In Pro Tools, those audio recordings are the Audio Clips ➏. But wait, this is a common misconception. Audio Clips are not the audio recording, they are based on a completely different concept, as we will see in the next section.

What Is In A Clip?

It is a general assumption that MIDI Clips are similar to the Audio Clip, they just contain different types of data. You might think that a MIDI Clip contains MIDI data and an Audio Clip contains audio data. Le't see what's really inside:

MIDI Clips

When you play your MIDI keyboard and record it in Pro Tools, it will record your performance as MIDI data. That data will be displayed in the Edit Window as MIDI Clips, the "container" of that MIDI data. Pro Tools can visualize the MIDI data and you can see it as dots and horizontal lines on those Clips. Like musical notation, this also is a "description" of music, just in the form of MIDI Messages or MIDI Events. Please keep in mind that, similar to musical notation, MIDI data doesn't have any "sound", they are just instructions and you have to send that data to a MIDI sound module that "plays" that data, like a real musician performing a score. 

Audio Clip (+ Audio File)

The Audio Clip is fundamentally different from a MIDI Clip. While a MIDI Clip functions as a container for the actual musical instructions (MIDI data), when you record an audio signal on the other hand, the Audio Clip does not function as a container for the audio data. The Audio Clip only contains the instructions to play the audio recording (i.e. play track 2 from 2:15 to 3:45) that is stored as a separate file. That means that an Audio Clip (the description) always requires that second component, an Audio File that contains the actual audio data:

• Audio Clip: Contains the play instruction
• Audio File: Contains the audio data

Here is a diagram that shows that relationship between the two components

Remember the DJ? You also have to give him two things, the actual CD ➊ and the instructions ➋ on how to play the CD and from where to where. In Pro Tools, the Audio Clip ➌ represents these playback instructions for the second component, the Audio File ➍ that is stored separately on your computer. Each Audio Clip in your Pro Tools Session is linked ➎ to a specific Audio File and that essential link information is included in an Audio Clip. It contains the name and the path to its linked Audio File, its so-called "Parent Audio File".

It should be clear by now that, in our example, a DJ cannot do anything with just the instructions ➋ if he doesn't have the proper CD ➊. In Pro Tools, this would be the same scenario when you have an Audio Clip ➌ (the instructions) visible in the Edit Window, but it cannot "play" the Audio Clip, because its Parent Audio File ➍ can't be found on your drive.

So keep in mind, when you look at an Audio Clip in Pro Tools, you don't look at the actual Audio File (the "pre-recorded music"), you look at the instructions for its Parent Audio File. The waveform that is displayed on the Audio Clip is just a "look-up" from the Parent Audio File that helps you edit the Audio Clip visually (change the play instructions).

Storage Location

One important question about MIDI Clips and Audio Clips is where the actual data is stored.

• Session File ➊: Your Pro Tools Session is stored on your hard drive (or in the cloud) as a Pro Tools Session File that includes all the data of your Session (without the "assets"). Pro Tools | First, as a cloud-based solution" uses the term "Project instead of Session, because Pro Tools now uses the "Project" term for Sessions stored in the cloud. 
• MIDI Clips ➋: All the MIDI data of your Pro Tools Session, which means all MIDI Clips, are saved with the Pro Tools Session File ➊.
• Audio Clips ➌: The data that is included in the Audio Clip is also saved with the Pro Tools Session File ➊, but, as we know by now, that represents only the play instructions, not the audio data.
• Audio Files ➍: The actual audio files are not stored with the Session File. They exist as individual files on your hard drive located in the Session Folder or anywhere on your drive (depending on your preference).
• Link ➎: The reference that links each Audio Clip ➌ to its Parent Audio File ➍ is stored with the Audio Clip, and therefore, in the Session File.

Graphically Enhanced Manuals

I hope you found this tutorial helpful. If you are interested in learning more about Pro Tools, check out my book “Pro Tools | First 12 - How it Works” or any other title in my "Graphically Enhanced Manuals (GEM)" series. All the books are available as PDFs from my website, printed books on Amazon, and interactive multi-touch iBooks on Apple’s iBooks Store. 

Thanks for your time and interest,
Edgar Rothermich