Prepare the Audio File. Then upload the converted file to either Google Drive or YouTube.
Put audio inside Google Slides. Open Google Slides, go to the Insert menu and choose Video. Here you can either select the file from your Google Drive or switch to the “By URL” tab and paste the link of any public YouTube video.
Turn on auto-play mode. Now that your video is embedded in Google Slides, right-click the video and choose Video Options. Check the setting that says “auto-play when presenting.” If you are using synchronized voiceover narration, you may want to change the start and end time of the video as well.
Hide the video player. Since you want the audio to play in the background, it may be a good idea to completely hide the video play from the slide. There are two ways to achieve this. You can select the video play, drag the resize handles inwards so that the player size becomes too small to be noticed. An even better option is to place the video player outside the slide area so it’s still part of the slide but won’t show during the presentation.
Click the Share button to get the link to your Google Slide presentation. Replace /edit in the URL with /present and you have a direct link to the presentation mode. You take any existing video from YouTube, place it on the slide in invisible mode and then turn on the auto-play mode so that the audio plays as soon as the slide is in focus.
In Normal view, click the slide that you want to add recorded sound to.
On the Insert tab, in the Media group, click Audio.
In the list, click Record Sound (in PowerPoint 2016) or Record Audio (in PowerPoint 2013).
The Record Sound dialog box opens.
In the Record Sound box, click Record, and begin speaking or playing your own audio.
Click Stop when you're done recording. Assign a name to the recording.
Click Play to listen to the recording. If you're satisfied, click OK to save the recording and insert it on the slide. If you're not yet satisfied, repeat steps 4 and 5.
The audio icon and controls appear on the slide.
In Normal view or Slide Show view, click the icon and click Play to play the music or other sound.
Power Point: Adding Audio From Computer
In Normal view, click the slide that you want to add a sound to.
On the Insert tab, in the Media group, click Audio.
In the list, click Audio on My PC, locate and select the audio clip that you want, and then click Insert.
The audio icon and controls appear on the slide.
In Normal view or Slide Show view, click the icon and click Play to play the music or other sound.