> For the complete documentation index, see [llms.txt](https://docs.sattern.dev/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.sattern.dev/tutorial/audio-graph.md).

# Audio Graph

As mentioned in the [Introduction](/master.md) section, Sattern operates around the Audio Graph concept. Audio Graphs are a way to house multiple "audio units" or nodes and interconnect them to each other.

Let's begin by adding some code to our "*main.js*" file that creates a new `Sampler` object and adds it to Sattern's main audio `graph` object.

```javascript
// main.js
// Arpeggiator
//
// Created by Jacob Sologub on 23 Jul 2020.
// Copyright © 2020 Jacob Sologub. All rights reserved.

const sampler = new sattern.Sampler();
sattern.graph.add (sampler);
```

The code on line `#7` creates a new `sampler` object and the code on line `#8` adds the newly created `sampler` object to Sattern's main `graph` object. You can copy the above code snippet and replace the contents of your "*main.js*" file. Press `Command + R` or `Command + S` to save and re-load the current file.

{% hint style="info" %}
The default`sattern.Graph.add()`method connects the specified `node` (sampler) object's *default* output channel(s) to the `graph` object's *default* output channel(s). You can specify what channel(s) are connected explicitly if you want to for example only connect the `sampler` object's left output channel to the `graph` object's right output channel etc. Please refer to the [JavaScript API Documentation](https://jacobsologub.s3.amazonaws.com/sattern/doc/modules/_sattern_.sattern.html) for more details.
{% endhint %}

Samplers need some sort of audio file(s) to make sound, so let's add some sounds to our `sampler` object.

```javascript
// main.js
// Arpeggiator
//
// Created by Jacob Sologub on 23 Jul 2020.
// Copyright © 2020 Jacob Sologub. All rights reserved.

const sampler = new sattern.Sampler();
sattern.graph.add (sampler);

const sound = new sattern.Sound ("./mcg_mp_064.wav", { 
    lowKey: 0, highKey: 127, rootKey: 64 
});
sampler.add (sound);
```

The newly added lines `#10-12` create a sound object for the specified `.wav` file and sets the `lowKey`, `highKey` and `rootKey` properties that will be used to "map" the specified sound one it is added to the `sampler` object. Line `#13` adds the newly created `sound` object to our `sampler` object. Again, copy the above code snippet and replace the contents of your "main.js" file. Press `Command + R` or `Command + S` to save and re-load the current file.

{% hint style="info" %}
The sample being used in this example is taken from [Linux Sampler Project](<https://www.linuxsampler.org/instruments.html >)'s [Maestro Concert Grand v2](https://www.linuxsampler.org/instruments.html) library and can be downloaded below. Place this file inside the project's root folder.
{% endhint %}

{% file src="/files/-MCy1kCzGfTz2v-eSvrg" %}
mcg\_mp\_064.wav
{% endfile %}

{% hint style="info" %}
`Command + S` saves the current file being edited, and `Command + R` reloads the entire Sattern JavaScript context.
{% endhint %}

Now it's time to actually make some sound.


---

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