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

# Built-in (CPAL)

> The default. CPAL audio to your OS default device.

The built-in sink uses **CPAL** to play audio through your operating system's
default audio device. This is the default and needs no setup beyond installing
Rockbox.

```toml theme={"theme":{"light":"catppuccin-latte","dark":"min-dark"}}
music_dir    = "/path/to/Music"
audio_output = "builtin"
```

## Selecting the output device

CPAL plays through whichever device the OS reports as default. To change it,
use your platform's audio settings:

* **macOS** — System Settings › Sound › Output
* **Linux (PipeWire / PulseAudio)** — `pavucontrol` or your DE's sound applet
* **Windows** — Sound settings › Output

There is no per-application device picker built into Rockbox for the CPAL sink.
If you need multi-device routing on Linux, point Rockbox at a PulseAudio
*null sink* and route from there.

## macOS-specific notes

CPAL uses CoreAudio natively on macOS — no additional setup is required.
If you ever see "no audio output" on macOS only, verify that the correct
output device is selected in System Settings › Sound › Output.

## Format

Output is **S16LE stereo at 44 100 Hz**. Higher-resolution sources are
dithered down by the rbcodec DSP pipeline before they reach CPAL. To change
the output sample rate, set `play_frequency` in `settings.toml` (`auto`,
`44100`, `48000`, `88200`, `96000`).

## Switching to another sink

Edit `audio_output` in `settings.toml` and `rockbox restart`, or call:

```graphql theme={"theme":{"light":"catppuccin-latte","dark":"min-dark"}}
mutation { connectDevice(id: "<device-id>") }
```

…with a device discovered via mDNS — see
[Audio output › Overview](/audio-output/overview).