Maximum amount of speakers supported in a surround sound setup for Home Theater

I was thinking of doing the same thing to add 300s to existing Era100s but I guess it won't work as per Sonos.  I have added one 5 to my system and seems to work OK but a slight delay ( echo) with the sound but with music from Sirius radio sounds great, so if you group extra speakers you will have a slight delay. If your going to watch TV it may sound a bit off. (Echo) but it's up to what you like and if you can watch TV with that sound. Everyone has their own sound preferences.  Just my opinion.  Good luck.

So grouping two Sonos rooms together is entirely different than bonding speakers together in a home theatre Sonos room.  With bonding, each speaker is playing a different role, different audio channels effectively (atmos is a bit different).  The speakers are designed to work together.    Temporarily grouping a room with a Five in to your home theatre room does not have the Five playing an assigned role in the home theatre.  The Five is just playing a stereo/mono copy of the audio.

As far as the delay goes, speakers in your home theatre room are connected via 5 Ghz WiFi, which has limited range but faster than 2.4 Ghz.  This allows the speakers to play in near perferct sync with the video.  The grouped room is communicating over 2.4 Ghz and buffered for multiroom audio.  This also speakers in different rooms of your house to play the same audio.    When you are playing music streaming sources, everything is slightly delay so that everything is in sync.  No echos, other than speed of sound.  For TV sources though, you will hear an echo since the home theatre room plays early to match the video, and your other grouped rooms do not.

You are correct that everyone have their preferences, but I wouldn’t want to misleading one into thinking you can just add speakers as you wish to a home theatre room  if they want extra front speakers or extra side speakers.  That’s not what happens when you group Sonos rooms together.

Thanks for that reply and I get it but was thinking if returning my 5 for the reason you described, but was thinking of the 300s to enhance the sound much more than the Era 100s. So as described, if I group these 100s with 300s I will still get an echo? To be honest I didn't mind a bit of echo and only bothered my wife lol so I think I may just leave it as it is. Thanks again 

Grouping with the TV sound always gets you the delay on the speakers grouped with the TV’s Room.

There is no delay or echo with grouped speakers playing streaming (non-TV) audio.

What is playing when on speakers playing from the same streaming source individually (not grouped) can vary widely depending on the source.

Just to be clear: a Group of speakers playing music will be synchronized with each other. Audio associated with a TV playing in a surround room will be delayed as it is sent to a Group. This will cause issues if TV audio is played by a Group member located in the same physical space as the surround system. There may not be any noticeable issue if the Grouped speakers are in distant rooms.

There is a SONOS TV Dialog Adjustment that might help synchronize Group and TV Voice sync at the expense of some Lip Sync. Each situation is unique in this respect, your mileage will vary. Note that there may be some sync adjustments in your video sources and TV that may be productive or problematic as you fuss with sync.

OK another question.  I  want to add a gen3 sub to my system. ARK, mini sub and a set of 300s.  Now if I grouped a set of 100s and added a gen 3 is it possible? I  won't be running two subs at the same time, just in a different group. 

The stereo paired 100’s and their SUB will be a unique, separate Room that can be Grouped with other SONOS Rooms.

Thanks for that answer. So what I am going to do is purchase a gen 3 and connect it to go with my Ark and 300s,  the group the mini with my ser of 100s.  One set for listening to TV and the grouped set of 100s with the mini for music. This sound would be perfect for me. Thanks again and out to bestbuy tomorrow. 

Look for the Sonos Arc, not the Ark…;)