Musical Background plugin allows you to add an audio background to your nopCommerce store. You will be able to upload an audio file and play it for your customers. Also it is a great tool for voice promo. You can setup whether enable or disable on mobile/tablet, play on homepage only, play in loop, styles settings for volume icon: position, color, size etc. Customer will be able to enable/disable sound and store it in cookies. So if customer decides to disable sound, it will be disabled across the entire store.
For documentation and details please refer to this link
You can check DEMO on this page.