Hello,
I was using Roon for streaming audio from Roon core to my iPhone and listen to the music on iPhone with the DAC connected to it. Roon uses its own RAAT protocol and it works nice… Audirvana can only stream music to DLNA/UPnP servers… I found an app ArkMC that works as UPnP server on iPhone and allows streaming to iPhone from Audirvana, but it didn’t work good enough… Do you have any experience with this?