manual/include/gain-envelopes.html

<figure class=right>
<img src="/images/gain-envelope1.png" alt="Default gain envelope">
<figcaption>A gain envelope (in green).</figcaption>
</figure>

<p>
  In Ardour, every <dfn>region</dfn> has a <dfn>gain envelope</dfn>, which is
  normally hidden. Clicking on the Draw tool will cause all the gain envelopes
  on all regions to show themselves; these will appear as green lines with
  square dots (<dfn>control points</dfn>) at the beginning and end of each
  region. The vertical axis represents gain, with the top of the region
  representing +6dB and the bottom representing approximately -170dB. By
  default, the line starts and ends at 0dB; the control points can be moved up
  and down to change the amount of gain at that point.
</p>

<p>
  Gain follows the line between control points continuously during playback,
  and adjusts the gain for that region accordingly. It is completely automatic,
  unlike channel <a href="@@automation">automation</a>.
</p>

<h2 style="clear: both">Manipulating Gain Envelopes</h2>

<p>
  The default gain curve, by itself, is not very useful; in order to have more
  control over the shape of the gain envelope it is necessary to add extra
  control points. Clicking anywhere in the region where there are no existing
  control points adds a control point to the envelope; it will appear <em>on the
  line</em> at the X-axis of the mouse's current position in the region.
</p>

<figure class="center">
<img src="/images/gain-envelope2.png" alt="Complex gain envelope">
<figcaption>A more complex gain envelope.</figcaption>
</figure>

<p>
  Once added, a control point can be <kbd class="mouse">Left</kbd> clicked and
  dragged to the desired location. Hovering over a control point will show its
  current level in dB. <kbd class="mouse">Left</kbd> clicking a control point
  and pressing <kbd>Delete</kbd>, or <kbd class="mod3 mouse">Right</kbd>
  clicking a control point deletes it.
</p>