> ## Documentation Index
> Fetch the complete documentation index at: https://docs.rawchunks.space/llms.txt
> Use this file to discover all available pages before exploring further.

# Add an instrument with Layer

> Generate a new part guided by Master or selected lanes.

Use **Layer** when you want a new instrument alongside the source: a bass part, percussion, or a piano answer to a melody.

<Steps>
  <Step title="Choose what should guide it">
    Master is the starting reference. Use **L** on an ordinary lane to choose it as a Layer reference. Choosing an ordinary lane removes Master from the reference set; you can choose several lanes together.
  </Step>

  <Step title="Describe the new part">
    Open **STUDIO → Layer**. Under **ADD AN INSTRUMENT**, enter **INSTRUMENT**, then **SOUND DESCRIPTION**. Both are required.

    You can also supply **Song description** and **Instrument groups (comma separated)**. Use these for context; keep the new part's request in Sound Description.
  </Step>

  <Step title="Generate the layer">
    Layer currently uses **Flexible** processing. Select **LAYER** and wait for its take.
  </Step>
</Steps>

<Frame caption="Layer controls in an example Rawchunks project.">
  <img src="https://mintcdn.com/rawchunks/TJh732SoaqfpR6P6/images/app/editor-layer.jpg?fit=max&auto=format&n=TJh732SoaqfpR6P6&q=85&s=7fd1078d1a6ca0697f53c7bedd4c362a" alt="Layer panel showing instrument and sound description fields with the Layer action." width="911" height="620" data-path="images/app/editor-layer.jpg" />
</Frame>

The completed result appears as a take under **EXTRACTED**. Use the take's play button to listen, then [mount and merge it](/app/takes-merge) when you're happy with it. Online processing uses your [session budget](/app/payments).

To hear the new part alongside the song, mount it with **BASE**, keep **ORG** and **TK#** on, and adjust its placement. The [take controls](/app/takes-merge) explain how to compare and merge it.


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