manual/include/region-gain-adjustment.html

<p>
  Ardour allows adjusting region gain by a constant amount as opposed to
  adjusting gain envelope where it's possible to change it gradually over time.
  Like everything in Ardour, this is a non-destructive change. The result can be
  adjusted at any a later time or discarded altogether. Internally, region gain
  is an inherent property of regions, it can be edited directly in the region
  properties dialog.
</p>

<figure>
  <img style="width:50%;" src="/images/region-properties-gain-adjusted.png" alt="Region Properties">
  <figcaption>
    Region Properties
  </figcaption>
</figure>

<p>
  There are two additional ways to adjust region gain: by boosting or cutting
  gain with a 1dB step, or by normalizing audio.
</p>

<h2>Boosting and Cutting Gain</h2>

<p>
  The quickest way to increase or decrease gain of selected regions without
  involving the gain envelope is to use <em>Boost Gain</em> and
  <em>Cut Gain</em> commands respectively.
</p>

<p>
  These commands can be accessed via the main <em>Region &gt; Gain</em> menu or
  region's context menu. A much easier way is to use shortcuts:
  <strong>Alt+6</strong> boosts gain by 1dB, <strong>Alt+7</strong> cuts gain
  by 1dB.
</p>

<p>
  When gain is boosted or cut, the region caption in the bottom of the affected
  region specifies the amount in parentheses. In an example below, gain was cut
  by 2dB.
</p>

<figure>
  <img style="width:50%;" src="/images/gain-cut-example.png" alt="Gain cut">
  <figcaption>
    Gain cut
  </figcaption>
</figure>

<h2>Normalizing Audio Regions</h2>

<p>
  Audio normalization is a way to bring the amplitude of a signal to a target
  level by applying the same amount of gain to an entire piece of audio data.
  Unlike other ways to treat perceived loudness, such as compression,
  normalization retains the original dynamic range.
</p>

<p>
  Normalization is a common step in exporting an entire project to an audio
  file. However, with Ardour, it's also possible to normalize some of the
  regions. This effectively changes the region gain setting, the same one that
  the boost/cut gain commands change.
</p>

<p>
  Region-level normalization in Ardour can be accessed via the <em>Region &gt;
  Gain &gt; Normalize…</em> menu command
</p>

<figure>
  <img style="width:50%;" src="/images/normalize-region-settings.png" alt="Normalize Region">
  <figcaption>
    Normalize Region
  </figcaption>
</figure>

<p>
  The normalization tool locates the part of the audio region that has the
  largest amplitude and adjusts the whole region so that that part matches the
  normalization target. In an example below, an audio region was normalized
  to -3dBFS, which led to -2.5dB gain reduction, and this is the part with the
  largest amplitude hitting the exact -3dBFS target:
</p>

<figure>
  <img style="width:50%;" src="/images/peak-normalization-zoomed-in.png" alt="Normalized region, zoomed in">
  <figcaption>
    Normalized region, zoomed in
  </figcaption>
</figure>

<p>
  It's also possible to apply additional constraints by analyzing perceieved
  loudness of the material. The first option is to constraint root mean square
  (RMS) to a certain amplitude value. The second option is to constrain loudness
  units (LUFS) to a certain value.
</p>

<p>
  The normalization tool will use the peak amplitude value, but will also
  correct the calculated gain adjustment when the constraint demands that.
  In the example below the same region as in example above was normalized to the
  same peak amplitude of -3dB but with an additional constraint of -21LUFS.
  The normalization tool took the peak amplitude into account and made sure it
  wouldn't exceed the target value of -3dBFS, then adjusted the region gain
  further from -2.5dB to -3.3dB to meet the LUFS constraint demands. This
  resulted in the peak amplitude hitting -4.2dBFS rather than the target -3dBFS.
</p>

<figure>
  <img style="width:50%;" src="/images/peak-normalization-with-lufs-zoomed-in.png" alt="Normalization with LUFS constraint, zoomed in">
  <figcaption>
    Normalization with LUFS constraint, zoomed in
  </figcaption>
</figure>

<h2>Resetting Gain</h2>

<p>
  To reset gain correction for a region entirely you can either set it to
  <tt>0</tt> in the region properties dialog or use the
  <em>Region &gt; Gain &gt; Reset Gain</em> menu command.
</p>