# Controller Rack

Controllers are used to vary the position of a knob or other control over time using another signal such as an LFO waveform. They differ from automation because automation uses a shape drawn manually and usually the shape is not a repeated pattern. In contrast, LFO controllers use waveforms to yield a regular pattern.

![Controller rack](/files/-LuiMmxd0EeEcgji_9Ml)

The Controller Rack displays all the controllers created within this project.

There are 2 types of controllers:

* LFO controller
* Peak controller

The right-click context menu allows you only 1 options: "Remove this controller". You can change the names of the controllers by double-clicking on the current controller name.

## LFO Controller

LFO stands for **Low Frequency Oscillator**.

<img src="/files/-LuiMuj0XvUq_vTRE2MY" alt="" data-size="original">This button is the Controller Rack show/hide toggle button (F11). To add an LFO controller entry to the Controller Rack, click the Add button at the bottom of the window.

To edit the settings for a particular LFO controller entry, click the Controls button on the right side of the entry. The LFO controller settings are:

* 8 waveform option buttons
* 4 knobs
  * BASE: the center (or zero line) around which the wave oscillates
  * SPD: speed is the rate (frequency) of wave oscillation
  * AMP: amount is the size (amplitude) of the wave
  * PHS: phase offset is where in the waveform the wave starts its first oscillation
* 3 speed-multiplier option buttons

## Peak controller

A Peak controller allows you to use the volume peaks from an audio source to automate the values of a control. A Peak controller is similar to Gate, but with greater flexibility. Peak controllers commonly use the output signal of a percussion track to control the volume of a sustained sound on a different track. This results in the sustained sound being chopped up in time with the percussion. In LMMS, when you add a Peak Controller it is visible in the Controller Rack, but it's actually an **effect** applied to an FX-channel. If you click on the "Controls" button you'll get a window telling you to use the FX-channel's controls (magenta arrow). Therefore, to get to the Peak Controller settings, click the "Controls" button on the Peak controller entry in the Effects chain box (yellow arrow). Beware an FX-channel can have more than one Peak controller entry.


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.lmms.io/user-manual/navigating-lmms/controller-rack.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.