manual/include/control-masters-mixer-strips.html

<figure class="right">
  <img src="/images/vca-numbered.png" alt="A VCA mixer strip">
  <figcaption>
    A VCA mixer strip
  </figcaption>
</figure>

<p>
   Although track/bus <a href="@@the-track-and-bus-group-list">groups</a> offer a certain
   kind of grouped-control over gain, solo, mute and more, traditional mixing consoles have long had
   group master channels ("<abbr title="Voltage-Controlled Amplifier">VCA</abbr>s") which allows to combine
   both a single fader to control the group level while also allowing you to easily adjust the relative
   levels inside the group. For large projects, this can make mixing much easier to control.
</p>
<p>
  Ardour implements those <dfn>VCAs</dfn> in a way that allows to use either or both
  of the conventions used on different traditionnal consoles for combining multiple masters:
</p>
<ul>
  <li>Nest VCAs (VCA 2 controls VCA 1 etc.)</li>
  <li>Chain VCAs (VCA 1 and VCA 2 both control track or bus <em>N</em>)</li>
</ul>

<h2>Description of the VCAs</h2>

<p>
A VCA strip is made of (from top to bottom in the screenshot):
</p>

<ol>
  <li>Number of the VCA</li>
  <li><kbd class="menu">X</kbd> button: Allows to hide the VCA strip. Left clicking this button toggles the exclusive visibility of the tracks connected to this VCA</li>
  <li>Name button</li>
  <li><kbd class="menu">M</kbd>: mutes the VCA, <kbd class="menu">S</kbd>: solos the VCA</li>
  <li>Level meter: allows to adjust the level of the VCA</li>
  <li><kbd class="menu">~vca~</kbd>: a VCA button to optionally connect to another VCA</li>
</ol>

<p>Right-clicking the name button shows a context menus comprised of:</p>
<dl>
  <dt>Rename</dt><dd>Renames the VCA</dd>
  <dt>Color&hellip;</dt><dd>Changes the color of the VCA button in the tracks connected to this one</dd>
  <dt>Drop All Slaves</dt><dd>Deletes all connections to this VCA, i.e. no tracks are controlled by this VCA anymore</dd>
  <dt>Remove</dt><dd>Deletes this VCA</dd>
</dl>

<h2>Connecting to a VCA strip</h2>

<img class="left" src="/images/connecting_to_vca.png" alt="Connecting to VCA">

<p>
	Connecting a track/bus/VCA to a VCA is as simple as clicking the VCA button that appears on any mixer strip
  under the main fader and choosing the VCA to connect to.
</p>

<p class="note">The VCA button only shows up in mixer strips when at least one VCA exists, i.e., a
  VCA must be created <em>before</em> connecting tracks to it.</p>

<p>
  Clicking the VCA button shows all the VCAs in the session, and any or all of this VCA can be checked
  to link them to the track, making this track controlled by multiple VCAs. The track will then show
  multiple buttons. Disconnecting a VCA from a track is done by unchecking this VCA in
  the list that pops up, or clicking <kbd class="menu">Unassign All</kbd> to disconnect from all VCAs at once.
</p>