You won’t be able to connect two Subs to the Amp, you can only connect 2 Subs to the Arc (a home theater setup). You could, however, group the two rooms, and get them to play the same music that way. The Sub would remain bonded to the Arc, though, so you’d need to be careful about the WiFi reach. 

Thank you, I wouldn’t want to use 2 subs with the amp.  It would be 2 subs with the arc and the. Occasionally remove 1 sub from arc to add to the amp setup.   This would be once a month, I was curious about how tedious it would be.  Is it a simple switch or does it take a long time to migrate?

If everything is working right a few minutes to switch either way but you’d have to run Trueplay again after each switch.

I’d go with leaving them both on the Arc and either adding a powered / wired non-Sonos sub for the Amp or a third Sonos Sub. However that may not be happy outside.

Tedious is a relative term, unfortunately. It’s quite a few clicks on the controller, and as @Stanley_4 says, you’ll be losing any TruePlay setting every time. 

I’d try it once or twice, to see what you’re facing. For me, it would be extraordinarily tedious after two or three times through, it isn’t a simple button switch, you’re essentially adding a ‘new’ sub to each room every time you do it. I wouldn’t find the benefit equal to the work, and would just leave them where they are. But I likely have different ears, different tolerances, and different music than you do. This is a personal taste thing, what I, or anyone else says is relative, not your truth. 

Thanks for the info, I hadn’t considered true play.  Definitely gave me something to think about!