Also, I ordered another pair of Era 100s so will be setting up four Era 100s in the corners tomorrow to start.  I’m hoping to use an Echo I have already which controls a receiver and a pair of B&W monitors (via aux cable) to control the Era’s.  I understand that they are separate so will not expect them to play in phase.

I’m hoping four Era 100s are a good start and will add two or four more along with a sub or two to finish it off.  

What does ‘in phase’ mean, to you? If they’re set up as either mono ‘rooms’ (one speaker), or stereo rooms (two speakers), they’ll still play in sync. It’s what Sonos (when grouped) is designed to do. 

Just FYI….

In an area as large as yours I suggest you starting thinking in terms of a “Space” that may have Multiple Rooms”.

As was suggested you may want to have a speaker in each corner and a pair in the center across from each other. If you want to control the speakers in the corners separately versus those in the center you’ll configure two Rooms in the same Space. 

One room might be named “Four Corners” the other named as “Center”.

You can then stream to either room individually or Group them together.

Grouping can be done on the fly or you can create a Group name or simply tap a Sonos pre-configured Group called “Everywhere”.

Learn about Grouping here or come back to the community for assistance 😊

The Sonos must be Grouped to play together, if not it wouldn't be a phase issue but each playing different music. Even if you try to start them together (not going to work) they will soon be playing sections of the track seconds apart or even different tracks from your source.

Trying to bring in a non-Sonos device will make that worse. 

Group all Sonos, maybe use your Echo for control if the Sonos options aren't working. 

I believe the OP was referring to phase/being out of sync between the receiver/B&W speakers and the Era 100s.

When I mentioned “in phase” I imagined I could play music on the echo which is connected to a receiver via an aux cable and pair of hardwired speakers, and then also extend to play on the “workshop” room of the Sonos speakers (however many I end up with). The “in phase” part was whatever delay there was between the hardwired output and the wireless feed to the Sonos. I’m not sure that simultaneous play is even possible. My four speakers should arrive overnight so I can set them up tomorrow morning and test them out. 
 

fingers crossed…

Ah. Every Sonos analog line in has that 75ms delay, which puts the Sonos system ‘out of phase’ with other speakers that aren’t also delayed. The best way to ‘fix’ that is to send the data to Sonos first, then play the output from the Sonos on all speakers. Of course, that requires a Sonos Port (or an older CONNECT). The Era 100 (all versions) has no outputs other than the speakers.

Honestly, you’re probably better off with just the Sonos devices, and forget non-Sonos speakers. 

How does the size and shape of your space compare to the auto shop that you like?

Keep in mind that the speed of sound is pokey at about one foot per millisecond. This means that the speaker at the far end of the space will be about 80ms out of sync. Unless you approach this system as if it is a music hall that probably uses a large speaker array at one end of the space, possibly with smaller speakers in the rear that incorporate a time offset, I recommend using multiple speakers along the long walls. Speakers every 10-15ft would allow you to be relatively close to a speaker that would dominate at your current position, minimizing the influence of more distant speakers. However, this cannot be perfect because the side walls are 50ft.

Another approach would use three speakers along each sidewall, separated by 50ft. Alternate left and right along the wall. SUB’s in corners will be most effective, but may not sound the best. You’ll need to experiment.

If you have an office area, consider using a local pair of speakers for that area.

All speakers in a Group will be time aligned with each other, but this cannot overcome the physics of pokey sound travel.

I setup the two pairs of Era 100s this morning and they sound great.  Bass response is much better than expected, and I’m not sure I’ll need a sub.  I went ahead and ordered a third pair, so will have one in each corner and two in the middle facing each other. 

I found that for seemingly less “conversational interference” (having normal conversation while in the space) placing them higher seems better.  I’ve placed three of the four at ~10’ high; the fourth is ~6’ high under a steel and concrete staircase, but may relocate it to ~16’ at the top of the stairs.  I’ll experiment when I get the third set, but will probably end up with more of a “commercial space” setup than something with soundstage in mind, which is fine since my aging ears are failing as I type.

I was able to integrate with Alexa, as well as add my Spotify and Sirius accounts to the Sonos app.  Now I have to learn and experiment with all the nuances of rooms, groups, volume synchronization, Trueplay, stereo vs. mono, placement, etc.

Thank you all for your suggestions and guidance.  I’m on my way to being a Sonos convert and will have to get additional speakers for the living space.  Since I don’t have to run speaker wire I may setup a 5.1 system in the living room rather that the 3.1 I have now.  Much research to be done...

Look at an Arc Ultra and Era-300 setup, not only 5.1 for older content but full Atmos support with a lot more, well channels isn't the right word for Atmos, so amplifier/driver sets? Add a Sub or two if needed.

Also enjoy the speech ehancement for dialog options that are a great match to failing ears.