Hi @Jdriesen, welcome to the Sonos Community!

I also like to use Spotify, it’s my main music service. Unfortunately, there isn’t a way to make it always default to the Sonos Arc and Sonos Sub as an audio output. I’d recommend you reach out to Spotify as this is a feature you should request with them.

You aren’t able to do this in the mobile or desktop Spotify app, only specific what device you want to connect to. Generally is stays on the output you selected, but it can go back to the device the app is installed on. This is just from my knowledge by using the Spotify app.

As for using Spotify with the Sonos app, since you only have the Arc and Sub, if you initiate playback from the Sonos app, it will automatically play to the Arc and Sub combo. This sounds a lot like what you’re trying to accomplish, so I’d recommend you give this a go.

I hope this information helps!

Many thanks for that. I did eventually figure out that I can play spotify from the Sonos app, but now have the problem that I can’t use the physical phone buttons to control volume. I’ve contacted Sonos and so far they haven’t been able to remedy that. Seems like it’s always tough when you combine products from different manufacturers. 

Actually using the iOS Shortcuts app, you can create a Personal Automation that will auto-connect AirPlay to your desired speaker when you open the Spotify app. Again this is just using Airplay though not Spotify Connect. To be able to use Spotify Connect, Spotify would have to add Shortcut support for their app which I’d doubt they’d do.