The best Atmos system you can get from Sonos speakers is:

• Sonos Arc
• Two Sonos Subs (at least one needs to be a Gen 3)
• Two Sonos Fives as rear surrounds

That’s the best you can do. No other combination of Sonos speakers would improve on this 5.2.2 setup.

Be sure to connect the Arc to a TV equipped with HDMI eARC, especially since you are using a Blu-ray player so you can get Dolby TrueHD/Atmos and multichannel PCM from the Arc. (NOTE: Sonos doesn’t support DTS).

If your TV only has HDMI ARC, you should add the HDFury Arcana to your setup to bypass your TV’s limitations.

So the “5” (in 5.2.2) is married to a sound bar? One can’t put a 5 (speaker) in the front (as Front Left, Front Right) instead, with maybe a One (speaker) for center?
And an Arc soundbar is the only way to get upfiring channels into an all-Sonos system?

Yes, to all of the above.  

I would also add that although you can use Fives for the rear surrounds, it is considered overkill for surround sound duty.  A pair of Sonos One SLs will work just fine.

Yes, the “5” is married to the Sonos Arc. The Arc alone is a 5.0.2 sound bar because it has side firing and upfiring drivers.

A Beam is a 3.0 sound bar but it does not support Dolby Atmos audio. Adding two rear surrounds to the Beam makes it a 5.0 setup.

The Arc is the only Sonos speaker that has upfiring speakers and the only speaker that supports Dolby Atmos.

You can’t mix and match any Sonos speaker to form a 5.1 home theater setup. A Sonos sound bar is the centerpiece of a Sonos home theater setup. The only Sonos home theater option that doesn’t rely on a sound bar is a Sonos Amp. But even with an Amp, you are limited to a 4.1 Dolby Digital setup using third-party front speakers.

I know all of this seems very limited, but that’s sort of the point. That’s how you are able to get a very clean and simple wireless setup using Sonos products. Sonos is not intended for die-hard home theater enthusiasts or audiophiles who don’t mind having bulky speakers all over the house. Sonos is for the average consumer who wants a better-than-average speaker that is affordable, looks cool, sounds great, and is really easy to setup and use.

If you can demo it somewhere before, then I'd personally do so with that move. I wouldn't bother having the rears as Play 5's, waste of money if you ask me, as won't be much difference to the Play 1's when used in that way. 

My real hope was that there was a way to have 5’s in front. Oh well.

Hah, not unless they open it up, which is highly doubtful. DTS and 7.1 is a no go either just to be aware. 

I don’t know that adding upfiring speakers is that much more complicated - it’s just another audio channel, and they already have the processing capability in the Arc, so it’ll fit everywhere. 

I’m not exactly a fan of the Nakamichis - the surrounds just look cheap, like a kid's first stereo speakers. But the setup there isn’t complicated, either, and it’s (kind of) wireless as well, with 7.2.4 and 9.2.4 options. I have to believe the folks at Sonos know how to achieve 4 upward firing channels wirelessly.

 

I’d call audiophile the MacIntosh-level, which Sonos definitely is not. But among regular consumer electronics, Sonos is definitely a premium brand as indicated by their pricing alone - it’s hard to say the average customer wants to spend twice on a 5.2.2 what they would for a competitor’s 9.2.4 of comparably easy setup. And Atmos is all over my local Best Buy - and while Sonos is represented there as well, I’d say that means the average user is also being marketed to for Atmos pretty heavily.

So yes, I agree that Sonos isn’t an audiophile ecosystem, but no, I don’t think Atmos is for die-hards at all, and among its competitors it certainly isn’t what I’d call “affordable”...not that this is deterring me from purchasing a Sonos system.

On the whole, though, another detailed, helpful answer. Thanks @GuitarSuperstar! 

The problem is, they shouldn't market the Arc as a full 3d sound, Atmos with bells and whistles bla bla bla etc like they do. Yes I know that's marketing for you, but the average consumer is getting sold something that isn't entirely true. Just need to look at the amount of threads and comments across various forums to see people say the upfiring side is basically ****! 

As for average consumer costs it can easily mount up. If you take into consideration you need an earc TV to gain the full benefit and if you were to throw in the sub and rears, that can easily hit £4000+ which isn't a cheap system. I know you have the arcana device, but that still means dropping an extra few hundred on that as well. 

Hopefully they will add some form of adjustments to the upfiring side and possibly look to adapt into the 7.1 side of things if not further, although I won't hold my breathe when it seems they are going to be dropping a painting with a speaker inside it partnered with IKEA. Yes we really need that... 

@Simmz I agree that the upward firing speakers on the Arc are lacking, but Dolby Atmos is much more than just height channels. There is a noticeable difference when I watch a Blu-ray with Dolby Atmos compared to a Blu-ray with just Dolby TrueHD. Atmos soundtracks sound more detailed and immersive to my ears.

Lets all hope that Sonos introduces a Sonos One SL with an upward firing speaker soon. I think this would make many Arc users very happy.