manual/include/waveform-display.html

<p>
  The display of <dfn>waveforms</dfn> (or, more correctly, <dfn>peak
  envelopes</dfn>, since the actual waveform is only visible at the highest
  zoom levels) is configurable via the <kbd
  class="menu">Edit &gt; Preferences &gt; Appearance &gt; Editor</kbd> dialog, to support
  different usecases and user preferences. The following options are
  available:
</p>
<table class="dl">
  <tr><th>Show waveforms in regions</th>
      <td colspan="2">By default, Ardour draws waveforms within audio regions. Disable this
      option to hide them.</td></tr>
  <tr><th rowspan="2">Waveform scale</th>
      <th>Linear</th>
      <td>This is the traditional <dfn>linear</dfn> (1:1) display of the
      peak envelope, or, at higher zoom levels, the individual samples.</td></tr>
  <tr><th>Logarithmic</th>
      <td>Alternatively, a <dfn>logarithmic</dfn> display of the
      peak envelope can be used. This will give a better idea of program loudness (it is similar
      to dBs) and plot soft passages more clearly, which is useful for soft
      recordings or small track height.</td></tr>
  <tr><th rowspan="2">Waveform shape</th>
      <th>Traditional</th>
      <td>The <dfn>zero</dfn> line appears in the middle of the display and waveforms
      appear as positive and negative peaks above <em>and</em> below.</td></tr>
  <tr><th>Rectified</th>
      <td>The zero line appears at the bottom of the display and waveforms appear
      as absolute peaks <em>above</em> the line only.</td></tr>
</table>