Dolby Atmos on the Samsung Galaxy S9 promises better sound quality on both headphones and the speaker. The Samsung Galaxy S9 is the first Samsung device to get it, but XDA Senior Member ImbaWind has ported it to the Samsung Galaxy S8 as well. All it does is modify the build.prop and the floating-feature.xml file along with including some libraries.
If you want to give it a try, you can flash it on any TouchWiz -based ROM from the thread linked below. If you want it on a custom ROM, you’ll have to ask the developer to include it. The best way to test if it’s working is to switch between music and movie mode. Note that if you want it to work on your speakers as well, you’ll need to install the APK linked on page 2 of the thread.
Dolby Atmos ported to the Samsung Galaxy S8