ardour-tutorial/content/mixing-sessions/using-plugins/index.en.md

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title = "Using plugins"
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_Plugins_ can be used to enhance or transform the sound of individual tracks.

They can be applied directly to a single track, or to a group of tracks using
a _send_. Later in this tutorial, we will discuss some plugins specific to the
Mixing process, such as _Compressors_, _Limiters_, _Parametric Equalizers_,
_Reverbs_ and others.

## Processor Box 

In Ardour terminology, a _processor_ is anything that gets plugged into a mixer
strip and treats the signal in some way. Ardour provides several built-in
processors such as the fader or panners. Processors can also be plugins used for
effects or as instruments, as well as sends or inserts which affect signal
routing. The arrangement of processors is arbitrary, and there is no limit to
how many there can be.

![mixer strip 2](en/ardour7-default-processor-box.png) 
 
The main space shown in the screenshot above is the _processor box_. The blue
box fader is in fact a _processor_ that comes by default inside the processor
box. It represents the fader that you use to control the track's volume. All
processors are shown as colored rectangles, with a small "LED" beside them that
lights up when the processor is enabled. The colour of the processor depends on
its location in the sequence; processors that are pre-fader are colored in red,
and post-fader processors are colored in green. 

## Adding a Plugin to a Track or a Bus 

Plugins can be added by right-clicking in the processor box of the track or
bus. A menu of options is presented. From the menu, new processors can be
inserted. 

![plugins1](en/ardour7-plugin-selector-in-menu.png) 

The _Plugin Selector_ is a convenient way to browse and choose plugins:

![plugins2](en/ardour7-plugin-selector.png)

From the _Plugin Selector_, you can search them by name, type, or other criteria
available from the drop-down menu. Let's add the reverb plugin called _ACE
Reverb_:

![Selecting ACE Reverb](en/ardour7-select-ace-reverb.png)

Once selected, click **Add** and the plugin will show up in the bottom list of
"Plugins to be connected". Then click **Insert Plugin(s)**, and they will show
up in the processor box.

![plugins reverb](en/ardour7-ace-reverb-added-to-processor-box.png)

## Editing Plugin Parameters

Double-click a plugin to edit its parameters. In this example, we double click
the "ACE Reverb" red box and get this window:

![freeverb settings](en/ardour7-ace-reverb-settings.png) 

Here you can control reverb parameters such as _Blend_ and _Room Size_. The
effect will apply to all sounds contained in the track. 

## Bypassing Plugins

To bypass the plugin, press the **Bypass** button in the plugin settings window,
or simply click the LED of the plugin in the processor box. This turns the
plugin off and allows the signal to pass by it unaffected. This is useful when
you want to compare how a track sounds with and without the plugin. 

![bypass](en/ardour7-ace-reverb-bypass-in-mixer-strip.png) 

Bypassed plugins are shown with the LED turned off. 

Right-clicking the plugins will give a menu with several options, including
_Delete_. 

## Pre-Fader vs Post-Fader

You have a choice whether you would like to add your plugin before or after the
fader rectangle in the _processor box_. Pre-fader plugins are inserted in the
signal path *before* the fader, so that the fader controls the level of the
signal coming out of the plugin. Post-Fader Plugins are inserted *after* the
fader: the fader controls the level of the signal going into the plugin.

For some plugins, Pre- or Post-fader placement does not matter. For others, the
difference is subtle. For others still, inserting them in the right place is
absolutely essential  (for more details, see for example [this
thread](https://discourse.ardour.org/t/fader-before-or-after-plugins/100666) at
the Ardour discussion forum).

## Plugin Formats

For those interested in learning more about plugin formats, here's a quick
overview:

**LADSPA plugins** are a somewhat obsolete plugin format mainly used on Linux.

**LV2** is an extensible successor to LADSPA. LV2 plugins are available on
Linux, Windows, and macOS, should respective developers choose to build them
for these systems.

**AU plugins** are the native plugin format for macOS and will only work in
that operating system.

**VST plugins** is fairly common on both Windows and macOS. Some VST plugins
built for Windows can be used on Linux, however they may not function correctly
and require 3rd party software to run. Others are built natively for Linux and
tend to work fine.

More information about using plugins with Ardour can be found
[in the user manual](http://manual.ardour.org/working-with-plugins/).

## Continuing

In this chapter, we learned how to add a plugin to a single track. This is
useful if that track needs a specific plugin, but if you have a plugin which is
used for many tracks at the same time, you should continue to the next chapter
about using sends. You can also continue to the various, plugin-specific
chapters such as _Dynamics_ and _Equalizing_.

Next: [USING SENDS](../using-sends)