Sound Across Slides in PowerPoint 2011 for Mac

If you want some music playing continuously in your presentation without any interruption when you move from one slide to another, then you should first make sure that the music clip you are using is suitable for this purpose. A soft music clip that spans across your slides can make the flow between slides smooth, as long as the sound is not jarring or distracting for your audience.

Also, if a presenter is going to speak along with the slides, then, it goes without saying that you don't want to add a sound that spans across slides. Not only will this make the audience inattentive, but the speaker will be at a distinct disadvantage too. Yet, if you are showing a bunch of successive slides that include pictures, and no speaker is accompanying the slides, then, adding a music clip to span across slides may be a good idea.

Follow these steps to loop a music or any audio file across slides in PowerPoint 2011 for Mac:

1. Navigate to the slide where you want the sound to begin playing, which is usually the first slide of the presentation. Now, insert the sound clip in this slide. By default, PowerPoint will embed the sound clip within the presentation.
2. However, you can opt to link it rather than embed it. Learn how to insert sound (and embed or link your inserted sound) in our Insert Audio (Sound) in PowerPoint 2011 for Mac tutorial.
2. When you insert a sound clip, PowerPoint will place an audio icon in the center of your slide. Select the audio icon, as shown in Figure 1, below.
3. 
   Figure 1: Audio icon selected
3. You will notice that selecting the audio icon makes the Format Audio contextual tab active on the Ribbon, as shown in Figure 2, below.
4. 
   Figure 2: Format Audio tab of the Ribbon

Contextual Tabs

The Format Audio tab is a contextual tab. Contextual tab is special tab in the Ribbon that will not visible all the time. They only make an appearance when you are working with a particular slide object which can be edited using special options.
4. This tab offers you different options to control the playback of the audio you have selected. Within the Audio Options group, click the Start drop-down list. From this list, select the Play Across Slides option, as shown highlighted in red within Figure 3, below.
5. 
   Figure 3: Play across slides option within the Start drop-down list
5. Now, click the Playback Options button to bring up the menu. From this menu, choose the Loop Until Stopped option, as shown highlighted in red within Figure 4, below.
6. 
   Figure 4: Loop Until Stopped option within the Playback Options drop-down menu
6. You might see an audio icon on the slide where you inserted the sound. If you don't like the icon on the slide, just drag it to anywhere off the slide, as shown in Figure 5, below. Your sound shall still play fine.
7. 
   Figure 5: Sound icon moved off the slide
7. Play your presentation to test how the sound plays. Save your presentation often.