> For the complete documentation index, see [llms.txt](https://stage-precision.gitbook.io/grid/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://stage-precision.gitbook.io/grid/timeline/layer-types/audio-layer.md).

# Audio Layer

Add and play audio files on a Timeline, route them through a Sound Card, control Layer and Item volume, use the audio Envelope for live logic, and monitor audio while scrubbing.

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The **Audio Layer** is used to play audio files directly from a Timeline.

It supports common audio file formats such as **WAV** and **MP3**.

Audio can either be added directly from Windows Explorer or assigned to an Audio Item after the Layer has been created manually.

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## Adding Audio

There are two ways to add audio to a Timeline.

### Drag an Audio File into the Timeline

Drag an audio file directly from **Windows Explorer** into the Timeline.

Grid Studio automatically creates an **Audio Layer** and adds the audio file to it.

This is the quickest way to add audio to a Timeline.

### Create an Audio Layer Manually

An Audio Layer can also be created manually using the normal **Add Layer** menu.

After creating the Layer:

1. Create a new Item inside the Audio Layer.
2. Select the Item.
3. Select the desired audio file in the Inspector.

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## Audio Output

To hear audio from an Audio Layer, a **Sound Card module** must be assigned to the Layer.

If the required Sound Card module does not yet exist, create it first in the **Project Tree**.

The Sound Card can then be selected as the output for the Audio Layer.

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## Layer Volume

The Audio Layer provides its own **Volume** parameter.

This controls the overall output level of the complete Layer.

Individual Audio Items also have their own Volume setting, allowing the level of each audio file to be adjusted independently from the Layer Volume.

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## Envelope

The Audio Layer provides a read-only **Envelope** parameter representing the current audio envelope level.

This value can be used elsewhere in Grid Studio to create logic that reacts to the audio signal.

For example, the Envelope can be used with:

* **Modifier Nodes**
* **Parameter Change Events** in Workflows

This makes it possible to use the audio signal itself as a live control source for other parameters or Workflow logic.

***

## Trimming Audio

The time range of an Audio Item also defines which part of the audio file is played.

Adjusting the start or end handle trims the corresponding section of the audio file.

For example, moving the start handle forward not only shortens the Item on the Timeline, but also moves the playback start position further into the audio file.

For general information about moving and resizing Timeline Items, see **Working with Layer Items**.

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## Scratch

Enable **Scratch** to output audio while manually scrubbing through the Timeline.

When enabled, moving the Playhead back and forth across the Timeline ruler produces the audio corresponding to the current Playhead position.

This makes it possible to hear the audio while quickly navigating through the Timeline and can be useful when locating or aligning a specific point in an audio file.

When Scratch is disabled, manually scrubbing the Playhead does not produce this live audio output.