Welcome, this is Terry Ewell, and this is you video on viewing sound in audacity. Audicity is the digital audio workstation that we will be using in this course. It has some good basic functions that will be adequate for what we are doing in this course.


I suggest that you open Audacity and that you follow along with this video. So this will serve as an introduction to some basic features in Audacity.
I am at the website right now on Unit 1. I have scrolled down to viewing sound in Audacity. We have here three sound files that are available. The first sound file is in a format called “mp3.” This is a very common compressed sound file format that is used now a days. These other two files are in “wav” which is “wave” format. These are not compressed and therefore these are larger files. We will be using another compressed file format called “.ogg.” This is what we will be using to share our files with each other.


The reason we are using ogg in this course instead of mp3 is because the format for mp3 is owned by a company. This is why Audacity and other audio software does not come pre-installed with mp3 converters.
So in order to download a file on a PC I right click, and it I have this “save link as” option, it will allow me to save where ever I want in a file. Here I already have that file saved. If you are on a Mac you use control click for that.
So if you just click on the file itself, you will launch a player on the Internet that should give us some sound. But that is really not what I want to do; I want to down load it to my computer so I use right click or control click to do that.
Now in some instances when you download files you will not be given the option of where to put it. On a PC that file appears in the C drive, scroll down to “Users,” find your name, and then look for a file called “Downloads.”  You will find the file in that downloads area. In fact that is where the Audacity file is that I downloaded for this class.


OK, so going on here. I have opened Audacity. Now I want to bring in the file. You can use “Import.” I would recommend that. Find Audio. Go to the directory, I have made a directory for this file. Then let’s first bring in “Bumblebee.” This is me playing “Flight of the Bumblebee.” What you see here is the sound waves or the format of this particular file. You can see the energy. If the waves go beyond a -1 or +1 then that means it has distortion, or has “clipped out.” It looks like it might have distorted there a little bit. This file has two tracks, that means that it is in stereo.


Up here in this section it is called the “transport.” This will play, pause, stop, and this is your record button. Well, let’s hear a little bit.

OK. Notice that we are getting the monitor showing the sound energy there. You can see that it clipped a little bit. There is some red here. You want to avoid that. You can see from the line that most of the energy was here, the highest at one point. At this point it is a -12. With you sound files you generally want to be in this area. If you are below -18 you are way too quiet. You can see the sound file. I will do it again. You can see it moving along.
          
This is the meter. You can see the sound energy here.
One of the things I can do is to put my cursor in different positions by clicking on the track itself. Then I can start there.
OK, so let’s have a look at Analyze and have a look at the spectrum. So it is going to analyze right at that slice in the track. What you find is the bassoon sound. I have the most sound energy at these lower hertz levels. As we get higher and higher there is a considerable drop off, and by the time I reach a certain place there is no energy given by the bassoon. This allows you to look at the sound energy.

OK, let’s pull up another file. I am going to go to “Open” and bring up these two. Oh, good, OK! So here is our warning. I want to talk to you about this a little bit. Audacity will sometimes do its editing on the original file. That’s a problem, because it you are editing in Audacity and you are editing the original file, you cannot keep that original file in the form you had it in. So I suggest that you always click “Make a copy of the file before editing” and click “OK.”  You might want to go ahead and click here. Don’t warn again, “Always use my choice above.”  Do that for the first time, click here. You will always have a copy that you are editing instead of editing your original file.

OK, so we pulled up this first one. Let me pull up this other one: Low Pass Guitar. Again make a copy. This is not as fast, but it is safer.

So I have here two files. Again you can see that they are in stereo, there are two tracks. There… let’s compare these two a little bit. This is actually the same original file, but I did some work on it. You can see that this file (top) has much more sound energy than this (lower) file.  Let’s take a look with our analyzer. Let me pick right here at this four second spot. I will pick the same place in both. So I am going to plot the spectrum. You can see the amount of the sound energy that is going through here. It is a pretty steady decline. Most of the sound energy was created here (lower Hz) then going up to 22,000 Hz. OK, I will slide that one off the screen.

Let me bring up the second file. This is our guitar low pass. Let’s again go to 4 seconds here. Let’s analyze that, plot spectrum. We have something very, very different here. OK, it took me a little bit “of doing” here but now we have both spectrums up.  So the audio file that was called “Low Pass” had a filter that started to take out the energy above a certain level. You can see up to this point (~3,000 Hz) they are the same, but starting at this point you can see that the sound energy is much less. That is a low pass filter meaning that it allowed the lower wave lengths to come through but the higher waves (frequencies) did not come through. If you listen to those two files, I ask you to do that later, you can really hear the difference between the two files. That is using what we call a “Plug in.” The low pass is a plug in. You will be using plug ins or effects later in this course.
So I hope that this has helped you a little bit to understand how to use these controls here, how to look at your sound files , and how to see your tracks  in Audacity. We will be beginning our work in the course there. Thanks, goodbye.