I've seen conflicting info so I'm not sure about this. I have a streambar (not the sound bar) and I have two questions.
1. Can I cast from my phone to the stream bar? I never see an option to select the stream bar for a device to connect to. Some posts say you should be able to but some of those posts mention the sound bar.
You can cast to the streambar but it is done only via the roku app. You go to devices in the app and you will see a media button. The gotcha is you can only cast locally saved music to the streambar. You can't cast from, let's say, Youtube Music. That's a bummer and deal breaker for me. To be clear, you can still open youtube and listen to music but you can't stream to the streambar from the YouTube app on your phone.
2. Can I stream music to the stream bar when the tv is off? I've seen many people say you can but I don't see how. The tv is turned off and so does the streambar. Granted, this may be related to item 1 so may be if that is resolved this will be too given both are not functioning by design.
This is showing to be false. After discovering the option above, I tried to test it starting with the tv powered off. The roku app shows the streambar connected so I select the media button and play the one local song I have. It powered the TV on and played the song thru "roku player". So, from what I can tell it does not work with the tv off.