The Arc Ultra already has a bass unit (the Arc has much less base), so I would not recommend a Sub Mini. I think the Sub is more fitting for the Ultra.

The Era 100’s would be fine. The Era 300’s are much more expensive, but you would benefit from a better Atmos experience. The IKEA Symfonisks (if you can still get them) could also be worth a look.

Thanks for the reply, so a sub 3 or sub 4 ideally?

That would be my choice, yes. FYI, I use an Arc Ultra (that replaced my Beam) with a Sub (Gen 2), a One and a One SL.

The Sub 4 offers some things the older Subs don't, darned if I can remember what this early and with no coffee yet. If you are choosing you might hope someone posts more info on that.

Since I had a "one item" discount and the Ultra set counted as one thing I got a Sub 4 but I can't hear any differences with my older Subs.

The 300s are amazing if you can place them in good locations but the 100s sound pretty good and are more flexible in placement. I moved (due to spouse pressure) my 300s to another room as an Atmos/Stereo Pairand am satisfied with the 100s as surrounds.

Thank you Stanley. I like the idea of flexible placement for the 100s. Are they immersive enough for things like sports and TV watching?

They absolutely would be immersive enough. Like an earlier recommendation, I have the Ikea Symfonisk lamps as my surrounds (no guests ever know where the sound is coming from!) and, being built on the Sonos One, they are amazing for surround and Atmos. The Era300s have upfiring speakers for the ultimate Atmos but what I use remains amazing. So the Era100s - the new Sonos One - would be equally satisfying.

Thanks Rhonny, i will probably get the Era 100s and sub 4 or gen 3, hopefully should fill the room nicely!

Big difference in 300s and 100s for Atmos,  ot much for 5.1 that mylimited testing showed me.

Even for Atmos the 100s are pretty good, I have no plans to upgrade mine and fuss with making the spouseless happy with the greater room intrusion.

Thanks Stanley, it just looks like the Era 300s are big and clunky but maybe they dont look so bad!

It isn't so much the looks but the placement recommendations. If you can come close to meeting them then the 300s are a great option.

The wall juts out either side of my couch so would be concerned that they'd both be too close to the wall and it would lose the effectiveness 

I highly suggest, first purchase Sub 4. Then depending budget go Era 300s or 100s. Era 300s are really best choice between the Era series if use lot Atmos.

If recall correctly, Sub 4 mostly geared to be more future proof than Sub 3. Mostly due to more memory inside and probably better processing hardware stuff.

If future proof not a concern, Sub 3 may be best choice from price standpoint.

Think Sonos recommends 8 inches of clearance around the Era 300s and 1 inch behind speaker.

Thanks, may not have the space then! You reckon 100s will be a good shout?

With size of your room Era 100s not be bad choice. But they are not designed be Atmos speakers per say.

You may get some virtual Atmos presentation. But how good? I use Era 100s throughout the house for multi-room music, not used as home theater. If you’re flexible and not looking for absolute, best possible experience it may surprise and could be great for you.

Definitely be fine if not big action movie viewer. Drama, thriller, etc, highly doubt will regret Era 100s purchase at all.

Cheers yeah mainly sports and tv, drama etc.. so hoping it would suffice for my needs. Without that 8 inches of clearance, I'm probably not getting the beet out of a much more expensive speaker