@IndyChad 

I haven’t a clue. However, you might consider calling Sonance or a professional installer. Also, remember...Sonance is an independent brand that Sonos has contracted to build in-ceiling and in-wall speakers compatible with Sonos ecosystem. Think tires by a manufacturer/supplier that an auto manufacturer decides to equip with one of their models.  

Cheers!

Thanks @AjTrek1 for the quick reply. I definitely understand the Sonos / Sonance partnership. I will look into contacting Sonance or a dealer with the same question, but thought i’d start here first since this community has always been helpful (and quick to respond). 

It does appear that Sonos speakers were created very close to the Sonance ceiling spears but they are not identical to any of their existing models which makes it hard to determine specs and potential accessories. If the Sonos architectural were just a “white-label” of a particular Sonance model from a physical design standpoint then that would certainly make things easier. 

Still hoping to find someone on here that may have tried something and can share their input.

The Sonance folks would be my first stop for a purchased solution.

I’ve made my own boxes with decent results. ¾ particle board, sealed joints and cable access, gasket to the ceiling and stuffed full of fiberglass behind a layer of netting to keep it away from the cone.

@IndyChad, did you hear back from Sonance? I have this same question and Sonos recommended via chat to contact Sonance. Sonos didn’t offer a direct contact so I just sent them an inquiry through their website; not sure if they’ll respond. Let us know what did you end up doing. I’ll share any Sonance response if I get any.

@Stanley_4 -- I don’t have access to my attic to affix/seal the back box to the installed drywall on my ceiling. Any recommendations as to how to mount a back box to the speaker as its mounted onto the drywall?

@Jsf20 I got no reply from my email inquiry to Sonance. I found an aftermarket box somewhere online that said it could fit (it was pretty expensive as I recall) but ultimately decided to not get one. So far it hasn’t been a problem hearing much upstairs other than some faint bass which doesn’t seem to bother my kid sleeping in the room above it.