With my Lexicon MC-12 when playing a Blu-Ray source. When the program material is Dolby True HD, the down mix is to Dolby Digital. If the program material is encoded in DTS HD master, the down mix is to DTS. However, if the program material is encoded in Dolby Atmos, the down mix that I get is Dolby Digital EX. I will be trying another Dolby Atmos encoded disk to see if this happens again.