This morning I received the following question in an email:
You shared how to add sound to Google Slides. Is there a way to add music as background throughout a slide presentation? I have a teacher who is having her students create a slideshow about the Great Depression and would like music to play as students' work is being presented. Is that even possible?
Unfortunately, I haven't figured out a way to make music play continuously through all of the slides in Google Slides. However, YouTube's audio slideshow tool will let you play music in the background while all of your images play. Watch the video below to learn how to do that.
It should be noted that the annotations feature that is demonstrated in the video above will be removed from YouTube at the end of this month. If you want to include text in the images shown in your audio slideshow, I'd recommend creating Google Slides then downloading them as images to use in your YouTube audio slideshow.