manual/include/track-modes.html

<p>
  Audio tracks in Ardour have a <dfn>mode</dfn> which affects how they behave
  when recording:
</p>
<table class="dl">
  <tr><th>Normal</th>
  <td>Tracks in <dfn>normal mode</dfn> will record non-destructively&mdash;new
  data is written to new files, and when overdubbing, new regions will be
  layered on top of existing ones. This is the recommended mode for most
  workflows.
  </td></tr>
  <tr><th>Non-Layered</th>
  <td>Tracks using <dfn>non-layered mode</dfn> will record
  non-destructively&mdash;new data is written to new files, but when
  overdubbing, the existing regions are trimmed so that there are no overlaps.
  This does not affect the previously recorded audio data, and trimmed regions
  can be expanded again at will. Non-layered mode can be very useful for spoken
  word material, especially in combination with
  <a href="@@pushpull-trimming">push/pull trimming</a>.
  </td></tr>
</table>

<figure class="right">
  <img src="/images/a3_nonlayered_example.png" alt="Normal and non-layered overdubbing comparision">
  <figcaption>
    Normal and non-layered overdubbing comparision
  </figcaption>
</figure>

<p>
  The screenshot on the right shows the subtle difference between an overdub
  in <dfn>normal mode</dfn> (upper track) and one in <dfn>non-layered mode</dfn>
  (lower track). Both tracks were created using identical audio data.
</p>
<p>
  The upper track shows a new region which has been <dfn>layered on
  top</dfn> of the the existing (longer) region. It can be seen by the region
  name strips.
</p>
<p>
  The lower track has split the existing region in two, trimmed each new
  region to create space for the new overdub, and inserted the overdub region
  in between.
</p>

<p>
  The switch between normal and non-layered modes is a global setting available
  in the main toolbar.
</p>

<figure class="right">
  <img src="/images/non-layered-track-mode-enabled.png" alt="Non-layered track mode enabled" width="50%">
  <figcaption>
    Non-layered track mode enabled
  </figcaption>
</figure>