Control when a sound is played
By default, sounds are not played until you click the sound icon that appears on the slide. If you want a sound to play automatically when the slide is displayed, change the option in the Start drop-down list (found in the Audio Options group on the Audio Tools Playback tab) from On Click to Automatically.If you select On Click or Automatically, the sound automatically stops when you move to the next slide. To allow the sound to continue over several slides, select the Play Across Slides option from the Start drop-down list.
Loop a sound
If the sound file isn’t long enough, you can loop it so that it plays over and over again. This feature is most useful when you have a subtle sound effect, such as the sound of waves crashing, that you want to continue for as long as you leave the slide visible. To loop an audio clip, just select the Loop Until Stopped check box found in the Audio Options group.Hide the sound icon
By default, the icon representing an audio clip is visible on the slide during your slide show. Assuming that you have set the sound to play automatically, you probably don’t want the icon visible.The Audio Options group includes a check box titled Hide While Not Playing, but it hides the icon only when the sound is not playing; the icon is visible when the sound is playing.
The easiest way to get the icon off of your slides altogether is to simply drag the icon off the edge of the slide that contains it. The sound will still be a part of the slide, so it will play automatically when the slide is displayed. But because the icon is off the edge of the slide, it won’t be visible to your audience.