To insert some seconds of silence at any place of your clip:

  1. Put the cursor where you'd like to add silence
  2. Click Silence on the toolbar or hit Ins on your keyboard.
    or 
    Choose Insert Silence in the Silence menu.

As the result, you will see the dialog box where you can indicate the silence duration (in seconds and milliseconds). When you click OK, the silence will be added to the selected place.

Silencing a Part of a Clip

Sometimes you might need to silence a section of your audio file. It is useful if you have both presenter and background audio in your presentation and want to hear only one audio stream.

  1. Select the audio part on the timeline
  2. Silence it by clicking Silence on the toolbar (or Ins on the keyboard).
    or 
    Choose Silence Selection from the Silence split menu.