Arc

I’m rocking a first gen Arc with a Gen 2 sub and Era 100s as fronts and rears. It sounds fantastic in my space. I considered an upgrade to the Arc Ultra, but I listened to my neighbour’s and the juice isn’t worth the squeeze for me at current pricing. I’ll most likely hold on to my Arc until whatever the Ultra’s successor is.

For Atmos, you need either the Beam or the Arc. Sub and rears are not required, but definitely add to the envelope.

With the Arc, you'll notice height channels and some front L+R (if your room layout provides for sound bouncing off of walls), but to get a proper Atmos experience, you'll want 2 x rears. Era 300s are your best option there, but I use 100s and it still sounds immersive.

That thing still negates the upward-firing and side-firing speakers. Sonos even specifically recommends against enclosing the Arc.

Arc Ultra + 2 x Sub 4 + 2 x Era300s rear surrounds, and set “Music Playback” to “Full”. For a contained system for both movies and music, that’ll pack a punch.