The four in-ceiling Atmos speakers are 12 inch diameter, the R-L surrounds are def tech dual bipolar speakers with dual 6 inch speakers per side 4 speakers per speaker, and the rear surround speakers are Martin Logan. These are not full range but definitely not small. The L C R main speakers are Martin Logan Vantages with Martin Logan Stage center channel - with 2 SVS ultra 16 sb subwoofers. The reason i didn’t mention the 5.1 mix is because I only have listened to the Atmos mix.
Bipolar surrounds may dilute the impact of surround music mixes that have instruments panned to the surrounds.