You play a background music/soundtrack while displaying any post or page in WordPress. You can have a home page or any other custom page playing some music file automatically, you can choose music in adequacy with your website content or you can use it on pages showing photo galleries and slideshows etc.
Soundy Background Music
The plugin enables you to play music files in the background. It allows you to show a custom play/pause button that perfectly fits in your website theme, you can display the button on your posts and pages, you can set soundtrack, enable auto-repeat loop, set default audio volume and set other options from its admin screen.
Each page or or post on your website can have its own soundtrack. It is embedded in the page with HTML 5 audio tag which makes it compatible with all modern web devices like smartphones, tablets, laptops and desktops of all vendors.
To start using this plugin simply install and activate it. After activation visit your admin area dashboard Settings -> Soundy page and select your options.
Background Music Player Lite
Another plugin called Background Music Player Lite is also a good option. It provides WordPress users with a background music player and enables you to play tracks and radio streams on your website. It has tons of useful features and is highly customizable. See it live working here.