Also, we will be discussing some fairly "techie" based stuff in some of these articles. You may find yourself asking the question: "Why do I need to know this in order to make music with my guitar?" The truth is... you don't! But as the recording musician trend continues to develop and overtake the world, using and applying this knowledge will make you a more versatile, valuable player in an extremely competitive and weird environment. Plus, as you learn the ins and outs of your tools as a musician, your music will sound better just as learning how to use a drill or hammer properly improves your projects around the house. So enough rambling... Here we go!
When you first boot Pro Tools and select "New Session..." from the File menu, you will see this screen:
Just this screen gives us a lot to talk about! We will be dealing with creating a new session from scratch as opposed to using any of the provided templates. After you have a good understanding of basic session setup, you can go back to the templates and experiment with different layouts. Lets break down this screen.
Audio File Type: In Pro Tools 8, you have two different file type options: BWF .WAV (Broadcast WAV Format) or AIFF. Either of these formats will work inside Pro Tools exactly the same. There will be no difference in performance because they are essentially the exact same file information with different 'header info' (instructions on how the file is read) I would recommend using WAV simply because it is more widely supported among all Digital Audio Workstations (DAWs). As we get in to file management in more depth, we'll see how you can pretty much convert anything to anything, so starting with WAV is not imperative, but for most applications, can make your life easier.
Bit Depth and Sample Rate: These two terms are usually a mystery to any new recording musician. To understand them and learn how and when to use different settings, you will need to understand the relationship between the two.
Bit depth refers to the number of 'bits' you will need to capture a portion of audio. Bit Depth relates directly to amplitude or more simply put, sound level. If you think of this concept as the DAW taking a measurement of the audio level at a given point in time and then recording that level as a specific number. In a 16 bit file, there are 65,536 discrete levels that your computer can assign to a specific audio level measurement. This number doubles with every added bit above 16 bit so by the time you get to a 24 bit measurement, you have 16,777,216 different levels. In Pro Tools, you have the option to choose either 16 or 24 bit and either way; the computer is doing some approximating. When a level measurement is made, the computer rounds to the nearest whole number. It is pretty obvious when you look at the above numbers, that recording at 24 bit means a lot less approximating, and thus, better sound quality. So, bit depth refers to the level of audio at a specific point in time.
Sample rate is an expression of those level measurements OVER time. If you have a sample rate of 44.1 khz, your computer is taking a level (bit depth) measurement 44,100 times per second. What about the levels in between the measurements? The computer simply makes an educated guess based on the surrounding measurements and fills in the blanks. Think of it as a complex 'connect-the-dots' game. Just as with higher Bit Depths, higher Sample Rates mean less approximating on the part of your computer and software resulting in better sound quality. Consider the following chart for a clear visual explanation:
Common logic would tell us to just choose the highest settings all around and then get started. Not so fast. The Pro Tools system is designed to deal with much higher quality audio than we listen to in our cars, home stereos or MP3 players. CDs play back audio with a Bit Depth of 16 and a Sample Rate of 44.1. MP3s have similar specs but are even worse quality. Also, running a session at 24bit/96khz will eat up your disk space very quickly!
So why would any one record at higher than CD quality spec? When you record your guitar in to Pro tools, then you add a little EQ, then maybe some compression. Maybe you normalize the file after recording. All of these processes/effects cause a decrease in bit depth to the file you have just recorded. So if you start at 16 bit and you mess with your sound during the editing and mixing stage, by the time it is in a mixed song ready to be played for everyone, it is actually less than a 16 bit file. Recording in 24 bit gives you plenty of room with the drastically increased resolution to apply the necessary signal processing. There is one thing we must do if we are recording at 24 bit with the intent of delivering the world a 16 bit file. We must put a plugin called "dither" on our master track and set it to 16 bit. Read the rest of the article before you go to this step though!
Once we have our session settings, the first track you create will be a stereo master fader. Go to the Track menu and select 'new'.
Then, on the last slot under the 'inserts' section of the track, select the dither plugin from the menu.
Set the plugin to 16bit with noise shaping ON (this may be the default setting):
We'll get in to what dither actually does possibly in a later article. For now, just remember that when you are recording a session at 24 bit and need to have a 16 bit finished product for CD or MP3 delivery, you must dither the session down on the master track.
So what do we do with the Sample Rate? There are a lot of differing views on this. If you are recording for anything video related, you should work at 48khz because most of the time, you will deliver your finished product at 48khz. My view on this subject is that, really, unless you are in a high-class facility with a lot of outboard gear (usually compressors, EQs or other effects that are physical boxes and require you to send the signal in and out of Pro Tools a number of times) you should record at 44.1khz. There are certainly reasons to use higher Sample Rates, but for what we are doing, 44.1khz works very well. I have recorded almost all my personal stuff at 44.1 and have been very happy with the sound. This really isn't something to get too hung up on as learning how to properly arrange, write and mix is much more important!
Lets go back to the 'new session' screen and look at the last item, I/O settings. This section can really bite you if you are using different recording interfaces, or trading sessions with friends.
Before we dive in to getting your I/O setup tuned for you, lets get some terms straight. When we are referring to a "recording interface" we are talking about what some people call a "sound card." These two terms do not mean the same thing. Technically, a sound card is a card inside a computer to allow you to pass audio and is stock or consumer grade designed for merely listening to audio or making dictation recordings. Your laptop or desktop computer has a sound card built in to it. This is different from a recording interface. A recording interface is an external box usually connected to the computer via USB or Firewire to pass audio in both directions. There are special aftermarket recording interfaces designed as cards that are inserted into a computer, but these are still not generally called sound cards. They are audio or recording interfaces. This distinction is important as we get in to routing ideas later on.
Okay, back to I/O settings. Go ahead and create your session with the option "last used" as your I/O settings. Don't create your master fader just yet. You should have a blank session with no tracks. Go to the Setup menu and select "I/O..."
A screen will pop up that looks like this:
At the top of the screen, you will see what kind of interface I'm using at the moment. I'm using an Mbox 2 Pro. Below the picture and the name, you see all the inputs that are available to you. If you click on the output tab above the interface picture, you will see all of the outputs available. This screen is showing you what your hardware is capable of with its ins and outs. You can double click and rename labels to customize things and you can save off multiple settings. Here's where this can get confusing. If you get a session from someone else, or you're trading sessions with a friend who has a different interface, you're inputs and outputs may not line up with where they look like they should. We are going to make a default I/O setup for you so that whenever you start a new session, you can select a setting that will work for you. Or if you are loading a session from a friend, you can pull up your settings so that the session will work properly.
To ensure that you have only the paths that you need to work with your interface, select all of the paths by clicking on the first path and, while holding down the shift key, select the last path. Then press "delete path." After you have done this, press the "default" button, and new paths will appear that are guaranteed to reflect the interface you are using. Most of the time, there will be no change. This is just a safe guard. Do this for every tab (input, output, bus, insert).
You can then name things the way that makes the most sense for your workflow. For example, if you always have a mic plugged into input 1 and your guitar plugged in to input 2, you can rename them to be something like "Vocal In" and "Guitar In." In most cases you'll notice that inputs are linked as stereo pairs. To label a stereo pair, simply double click on the name of the pair. If you want to name a specific input, click on the arrow just to the left of the path and the two mono paths will be displayed, you can then name them whatever you want, while still being able to use them as a stereo pair if you need to.
Once you have everything named and organized the way you want, press the "export settings" button and name it what ever you want, realizing that this will now be your default I/O setup that you will use when creating new sessions. This will save you a lot of routing work later on if you do this now.
If you saved this setup in the default folder that came up with the save prompt, your new setup will show up in the drop down menu of the first "new session" screen we covered.
So, we have created a 24bit/44.1khz session with a custom I/O setup. Then we have created a master fader with a dither plugin. Hopefully some of the mystery of all those settings and numbers is taken care of for you now. In the next article, I will be going over the basics of the Edit Window and the tools that go along with it. Lets get this stuff out of the way and under our belts so we can dive in to making music!