Hello,
I was using Roon to stream music from Roon core to my iPhone and listen to it on iPhone with connected DAC. Roon uses its own RAAT protocol and it works amazing. Audirvana can only stream music to DLNA/UPNP servers… I found an app ArkMC that works as upnp server on IOS and allows streaming music to iPhone from Audirvana, but it didn’t work good enough… Do you have any experience with this? I was thinking about streaming it to RPI and connecting to RPI from iPhone, but I don’t have any experience with it, so maybe you guys could give a hint?