> For the complete documentation index, see [llms.txt](https://docs.lmms.io/developer-guides/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.lmms.io/developer-guides/core/internal-routing-of-events-and-signals/audio-signals.md).

# Audio signals

### Before mixing and mastering

`AudioPort` collects signals from audio sources(currently, `PlayHandle`s only) connected to it, apply audio effects, and provide the final result to its consumers.

The effects added to an instrument itself are processed by the `AudioPort` associated to the instrument.

### Mixing and mastering

At the mix & master stage of the audio rendering, `Mixer` is responsible to processing and routing signals. `AudioPort`s provide audio signals to the assigned channel using `Mixer::mixToChannel()`. Routing between audio channels are handled in `MixerChannel::doProcessing()`.