[turtle]

Originally Posted by Matsu hmmm... So I can control Sonos via Apple/Homekit, but I wouldn't be able to control Sonos without going into the Sonos app. I'm really the only one in the house who uses it for Radio, but I love being able to grab international radio stations via Sonos' numerous apps. I wonder how Apple does on this score: most radio stations have a web page where they stream their on-air content. Is Apple/Siri able to simply search the web, grab the correct publicly available stream and play it, all via voice control?

Not exactly, you configure and set up Sonos with their app. You can always control it with their app, but you can also control them with HomeKit integration. Volume controls and such work as expected.

If you want to use a Sonos specific source I'm sure you would require their app to do so. Of course, this can be iDevice or Mac/PC based.

I've not been able to get Siri to play anything that isn't from Apple Music. I understand you can integrate Pandora, Spotify and others now but general internet searches would refer you to your phone and then initiate play from it. You wouldn't be able to handsfree make that happen as it is now.