In particular there an audio clip of a helicopter overhead if you want to test what your upfiring speakers are actually giving you (PSB Imagine XAs are surprisingly impressive. I'm not sure if there could be copyright concerns (it does seem a bit grey, Dolby offer their content free to download anyway, but there is content from multiple movies - but then that is only select scene and not verbatim.) I'll leave that to individual judgement if you're interested - but I can say the Dolby demos discs are stonkingly good but there is one guy offering a three-pack set with copies of the 2014, 20 Dolby Atmos demo discs. Original copies on ebay are rare and expensive. Apple Music and Amazon Music include Dolby Atmos Music tracks in their standard 10 per month price tiers, while Tidal requires a more expensive 20 per month HiFi Plus subscription.

They will send lossless Atmos to your AVR - and have been developed by dolby to really show off the full extent of Atmos with Dolby created demos, select scenes from a variety of movies, music and sports etc. This demo showcases the ability of Dolby Atmos to create a sense of stillness and silence. The best source for demo-ing Atmos is going to be the Dolby demo blu ray discs (though you obviously need a compatible blu ray player).

2018 dolby atmos demo disc