looks to me like arc ultra has flat section at back to mount to wall, so maybe no mount needed….

I too would like to know this answer. Looking at them side by side, they appear barely different from one another. But why would they sell two different versions if the old was compatible with the new. Please let me know if you find out! 

It’s right there in the FAQ.  However, I thought I read somewhere that while the Arc mount will work, but you can see the mounting hardware from certain angles.  It’s not as hidden as the Ultra mount.

Thanks Danny!

Shouldn’t that say ‘Can I mount the Arc Ultra?’

It also seems odd that they don’t use the word ‘the’ in that statement. 

I think the wall mounts for Arc and Arc Ultra are different. They are listed as different products in the Sonos online store and they differ in weight. 

Would be good if Sonos had some clear guidance on it. Hopefully the mounting points are the same template even if the mount itself is different. Would save drilling new holes in the wall. 

It’s in FAQ

Will Arc Ultra work with the Sonos Arc Wall Mount?

The Sonos Arc Wall Mount will work with Arc Ultra, but, given the different dimensions of the products, the mount may be visible from certain angles. For this reason, we recommend using the Sonos Arc Ultra Wall Mount.

@paulrw 

Thx for clarification…. helpfull answer.

Yes, I screwed that up and screenshot from the Arc product page instead of the Arc Ultra. Below is the correct one.

No worries, and completely understandable ;)

However, I don’t think you have any control over the missing article ‘the’ in that odd sentence construction. 

It’s not important, and I’m no grammar expert, but I prefer it without ‘the’ to be honest.    You typical don’t use ‘the’ with specifically named entities, right?  Those don’t sound right to me.  “I’m going over to the Bobby’s house.” or “I’m going to the Portland”.  You do use it with unnamed entities. “I’m getting in the truck” or “I’m going to the city”.  The second you name your truck though (who doesn’t name their truck?), you drop ‘the’, because “I’m getting in  the Lucille” is just wrong.

Of course “the” could be part of a name.  “I’m going to what The Batman”.  But it’s called ‘Arc Ultra’.  Not ‘The Arc Ultra’.

Anyway, I digress on my digression.  I guess it depends on whether you consider Arc Ultra to be a named object, of the type soundbar, or if it’s an unnamed object, of the type Arc Ultra.  I lean towards the former, and that’s probably subjective as I don’t like the formality of using ‘the’ frequently.  It tends to give me the impression of giving more weight to what you’re talking about that is really necessary, if that makes sense.

The. 
 

Just to annoy you ;)

Remember… „The Bob“