Several enthusiast sites archive demo clips. These are often scenes from major blockbuster movies (like Blade Runner 2049 , Mad Max: Fury Road , or Ready Player One ) extracted from Blu-ray discs to test specific audio dynamics.
It sounds like you're looking for (typically short video or audio clips designed to showcase object-based surround sound). Here's what you should know: dolby atmos demo downloads
To play Atmos files on a PC, you generally need: Several enthusiast sites archive demo clips
Dolby Laboratories offers a selection of free trailers and demo clips on their website. These are the gold standard for testing because they are produced specifically to highlight the format's capabilities. Mad Max: Fury Road