Getting Started with AudioKit

Before we jump into code, let's first see what AudioKit can bring to the table. The best way to do this is to explore the AudioKit Cookbook, an open source app for Mac and iOS. In the application you'll find live demos that show off a number of concepts and tools that AudioKit provides. You can find the Cookbook here at github.com/audiokit/cookbook. Let's start by cloning this project and open it in Xcode. We'll type "git clone" and paste the URL. Then we'll cd into that directory and we'll open it up in Xcode. Once open, you'll see there is an XC config file that is missing from the project. This is intentional so that we can add our own development team ID so that we can build and run. This file is also ignored in source control so it won't be accidentally committed. We're going to go over here to this development team here and we need to create this file. I'm going to go over into our terminal and if we take a look in here, there is an Xcode config folder. Inside of there is a template. I'm going to copy that development team template. I'm going to use this bash trick to copy that template file into the same without the dot template extension. If you're not familiar with this bash syntax, it is basically going to take this whole argument, duplicate it, so it says if I typed it again here, but on the first time it writes it, it's going to use dot template and the second time it's not. What this is doing essentially is copying development team dot template dot XC config to development team dot XC config. Once that's there, then we can click on it in Xcode and we can see that we have our development team here. I've pasted in my development team ID and now we can go over to our application and we can build and run. If you're not sure what your development team ID is, you can go over here into the cookbook target, go into signing and capabilities. You can change this team to one of the teams in your list here and then if you go back to Xcode and do a get diff, you will see that this team ID got changed to this. You can also go to the developer portal under your account and membership details section to find it there. And I'm going to go over here and I'm going to pick iPad Pro to use as my target here. You can also use an iOS simulator or the Mac, but some of these demos in the cookbook application can benefit from having multi-touch. Okay, so this is the audio kit cookbook application and it contains live demos to show off the functionality of audio kit. So I'm not going to go over everything in here, but I encourage you to download and run the cookbook and take a look at some of these sort of mini applications or demos so that we can get an idea of what audio kit can do, but also we can take a look at the code for each one of these. So I'm going to start off by going to mini apps and arpeggiator. And the first thing you note is we have these, the keyboard display. This is a built-in control that we can use. We also have these knobs which we can control by tapping and dragging up and down or left and right. So this one controls the beats per minute and this one controls the note length. And an arpeggiator is going to take all of the keys that you press at the same time. It's going to sort of toggle between them in an interesting pattern. So in this case we can push this. And we get some sound. And we also notice that the sound waves are showing up in this view here. This is called the node output view. And we can attach this to any audio kit node to view what the audio samples are looking like at that stage. So if I hold down option I get multiple fingers here and once I have them sort of arranged horizontally I can hold shift to lock them in place. So we can play around with that. That's an arpeggiator. And if we want to find that in the code we can go over here to the cookbook common package, open up sources, find recipes, and then inside of here are the same categories we saw in the app. So this is the code for the arpeggiator. Now this is a little bit more complicated for us to take a look at just now, but the fact is that the code is there for us to look at and to learn from. Now let's take a look at let's say the drum pads. So these have different samples that you can trigger by tapping on one of these values. And I like this sample because as we talked about last time you can actually see the waveforms. So for the hi-hat it's a very high frequency sound. For the kick drum it's a very low frequency sound. So this sort of gives you a visual sort of reinforcement of understanding what these audio waves are doing. Okay let's go down to let's look at oscillators. So an oscillator is going to take basically these parameters for a frequency, for the amplitude, and then start playing at that frequency. So here's my frequency at 440 if you remember that from last time. And the amplitude is 0.2 so it's fairly low. I hit start and now we can see the waveform here. Now I'm going to turn the amplitude down so it's not so loud. And as I use the keyboard this is changing the frequency that is being played. We turn the frequency way up and I hit start up here. Let's see something like that. And I just bring the frequency down you can see the waveform changing. So that's an oscillator and in this case we're doing a sine wave oscillator. There's also a dynamic oscillator so in this case I'm again going to turn the amplitude down so it's not too loud. This may be just a little bit of a jarring sound just for warning. So if we start with the sine wave, actually this one is using the sawtooth wave. Switch over to the sine wave and you can see that it sounds smoother. The square wave sounds a little unnatural kind of like an old computer. If we do triangle wave it's not quite as natural but it's also not as harsh as triangle or sawtooth. Sawtooth being the most unnatural of all of these. And like I mentioned last time you can use that to your advantage. Sounds really good in certain situations but these are an oscillator that can take values from any number of signal generators. So sine wave generator, square wave generator, etc. And we can talk more about that a little bit later. Okay let's move on and we're going to take a look at uncategorized demos. I want to look at the audio files view. So this is something where even though we're not playing back audio, this is able to analyze the audio and present us a waveform overview of that audio file. Which is really useful if you wanted to create some sort of audio editing application or mixing application or something like that. And then the last thing I want to talk about is reverb. So let's look at the Apple reverb. So I'm going to pick a piano as the audio and we can start playing it. And you can hear the audio sounds like it's in a big room. We can change the type of reverb that is used. So if I use small room it changes it. We can use a medium room or a medium chamber. Each one of these is going to change the aspects of that reverb. And these are all built in. This is an Apple provided audio unit. So if we go over to one of these other custom reverbs. So I'm going to go to this one. I wanted to show this one because we can control all the parameters of the reverb. But also it shows you the input signal as well as the reverb signal. And then what we're doing here is balancing. So right here this is the mixed output is going to be the balance between the dry input and the process signal. So if I go to balance zero we're only going to be hearing the red. If I go to balance one we're only going to be hearing the blue. And then this will blend between the two. So again I'm going to choose piano or maybe this time I'll do female voice so we can hear something a little bit different. And I'll hit play. A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E Alright so that's a way to sort of play around with the different reverb settings for this particular type of reverb algorithm. And again all the code for these are in here which is really nice. Okay so that covers the AudioKit cookbook. I encourage you to play around with that on your own so you can sort of see all the different demos that we can work with. So I'm going to close this and let's go back over into Xcode and we're going to create a new project. So I'm going to, let's just go into Xcode, hit command shift N. We're going to create a new iOS project and this is going to be an iOS app. I'm going to hit next. We're going to call this AudioKit fun. And for the interface we're going to use Swift UI. Which will be Swift and these two can be none. Okay so we have a basic Xcode project for an iOS application here. And what I want to talk about now is how to integrate AudioKit into this application. Now we can right click here and say add package dependencies. And if we do that we get this thing here which is helpful and we can search and enter a package URL here. But AudioKit is actually made up of many packages. So if we take a look over here we can see all the different packages that AudioKit provides. And it depends on your needs so that you don't bring in too many things. This framework is broken apart into many pieces and you can pick the things that you need. So for all of these are going to depend on this AudioKit framework which gives us the basic sort of building blocks for audio synthesis and processing. If we need some C backed AudioKit DSP we can use this one. If we need controls and visualization for AudioKit apps we need this one, AudioKit UI. There's another controls one that has a bunch of knobs and sliders and XY pads and things like that. Let's see if we look at the sound pipe AudioKit this has oscillators and effects and filters. There's a bunch of different things here but I think that the main thing that we're going to be playing with are going to be AudioKit, AudioKit UI and sound pipe AudioKit. Maybe one or two others. Not sure yet. There's also a Swift library for music theory which we could take a look at if that's interesting. But basically if you're building a music based application and you need to calculate something like what are the notes in the major scale or you know given this note what is the major third above it or something like that then this is a Swift library that can support that sort of structure. Okay, so because this is made up of a bunch of different packages the best way to do this is to add a package collection. So I'm going to go over here and I've already added it but for you you can go over here and click on this and say add package collection. And the package collection is going to be https/swiftpackageindex.com/audiokit/collection.json. And I'll have this in the show notes so you can take a look at it and copy and paste it. You're going to click load and that's going to give you this collection right here. So at this point now we have access to all of those packages and we can easily just click and add them to our project. So I'm going to add audio kit and we can hit add package. Once it downloads it's going to ask us what we want to link it to so we're going to link it to our application target and we hit add package. We can do the same thing if we go back and add another package. This time I'm going to choose the audio kit UI. And you can see that that already pulled in controls. I'm going to do the same thing over here again for the sound pipe audio kit which we're going to use for oscillators. And then that ends up bringing in a couple of other packages. KISS FFT is a framework maintained by the audio kit team. This is for fast Fourier transforms. The audio kit EX is the C based ESP library that sound pipe audio kit uses. So now we have all of the dependencies that we need to get started with audio kit.