can multiple sonos subs be ran in a single room?

You can't add more than one Sonos sub to the connect amp. However, I can't see why you can't get a y-adapter and have two third party subs hard wires to the amp. The idea of having one of the subs setup in another room and grouping them would work...but the volume is dependent on the room the second sub is in. So you'd have music playing in the second room. It may sound weird too...because the crossover maybe different depending on what speaker the subs paired with. So after this muddy explanation (sorry) I wouldn't do it

You may want to try one SUB first and then determine if a second SUB is truly necessary.  Even in a large room, you'll be amazed at how much sound a single SUB is capable of producing.

You may want to try one SUB first and then determine if a second SUB is truly necessary.  Even in a large room, you'll be amazed at how much sound a single SUB is capable of producing.
I had one sub but it was not enough for my large room so I added a second. During music playback I have no issue with this setup. During movie/tv playback I have a huge issue with this. Your system is rigged for fake 5.1 sound. What I mean by fake is that 3channels go through the center playbar and your system doesn't allow me to tie in a play1 pair for true right/left sound. It does allow a surround pair for channels 4 and 5 though which I have a pair of play 3's assigned for. However I have a play 5 in my room also directly behind where I sit and watch tv. This is what the second sub is tied too, during movies I love having the extra bass especially since it feels more balanced with the two Sonos sub units in my 800sq ft living room. What I don't love is that on 5.1 Recordings that all 5 channels get pushed through the back play 5. It drives me crazy, a lot of times I ungroup it and then I lose my extra bass which also makes me unhappy! Sonos you need to update your software for both of these things:

A: you need to allow a second sub to be paired with the playbar if requested, some rooms are large. You could turn up one sub sure, but then it feels unbalanced and overkill. In my large room I need to space them out and create an even layered sound. Your hardwired rivals now allow two bass channels on their receivers so I recommend you all catch up or you'll lose my future business on other rooms in my home.

B: and this should be obvious. Allow channel control on your additional play1,3,5's in a home theater room. In other words allow me to program my play 5 to only receive surround channels when I watch 5.1 recordings. Likewise allow your user to create true 5.1 by allowing a pair of play 1's to be used as the right/left. It's awesome that you have the virtual 5.1 setup but until you create the update don't expec me to spend another $200 each on play 1's. For that matter without these updates I'll likely go back to hardwired speakers to enjoy true 5.1 with multiple sub units

@John M. I don't agree. I have a setup of 2 p1+sub+bar, room just next and B&O + connect + amp and 2 B&O Penta (300W) - hardly enough - so in large rooms you need some heavier than one sub - so how to do that? Otherwise SONOS rules!!

I agree. i have experience of multiple subs in one room and that is something I really miss with sonos, I also have a large livingroom which would sound much better with 2-4 subs.:D

I guess I don't quite see why you can't set up another "room" and pair the sub with that, and put the sub in the same room as your original sub, and just "group" the rooms. You'd end up with two (or however many you want to set up) subs in the same physical space, playing synced music.

I tried to do that two separate room install. And the problem is .. is that it thinks its is own room.. so the sound seems unbalanced.. i even went to the extreme to hooked up a Connect
To a powered subwoofer ..gives a little boom but still unbalanced.... but I believe a software update could definitely fix that issue I don't see what's the problem with adding another sub to an existing playbar...