Page-flipping publiacations created by 1stFlip Flash/HTML5 Flipbook Creator comes with default page flipping sound. If you don't want the page turn sound, you can turn it off.
First, please make sure the Sound Button is enabled, then click the below sound button. When it turns to , the page turn sound is muted.
You can also add background music for the page flipping publication with 1stFlip PDF to Flash/HTML5 Flipbook Converter. See: https://www.1stflip.com/flipbook-creator-mac/add-background-music-to-flipping-book.html.