One thing I found after doing this for a few days.... msgreenf had me follow instructions to create a group on Alexa for all echos. What I found was this plays whatever you’re asking Alexa to play on all your Alexa devices (as well as the speakers you turned on in your c4 system). Not on all music sources, but when I’m listening to radio, the echo device and the speakers were slightly off causing an echo (no pun intended) I figured out that no matter what echo/Alexa you’re talking to, you can say, “Alexa, play music on (insert the name of your echo connected to the controller). And bam, none of the other Alexa’s are playing at the same time as your house speakers. Loving the setup! Listening to more stuff on the speakers then ever! Sent from my iPhone using Tapatalk