Surrounds should be a little behind and to the sides of your main viewing area.  I’m not sure full details of your floorplan, but if they are in the dining room, they probably aren’t positioned properly for surrounds. 

If you add the Era 100s as surrounds to the Beam, the Era 100s basically become slaves to the Beam and all three speakers will now act as one zone. Any audio you play out of the Beam will also play out of the Era 100s. So if you want to only play audio out of the Era 100s, you need to add a different pair of speakers as surrounds to the Beam.

The surround speakers will not introduce a delay. When playing TV audio, the surrounds will play the surround audio from the audio mix. When streaming music, the surrounds will play in full stereo if you have the Music Playback setting set to FULL. If it is set to AMBIENT, the surrounds will only play ambient audio.

Thanks for your response. Fortunately, the Era 100’s are positioned near the beginning of the dining room space which, in my floor plan, happens to be a little behind and to the sides of my main viewing area.

Very helpful, thanks. My experience so far with grouping Living Room (Beam) and Dining Room (Era 100 stereo pair):

• Music streaming: Grouping the Beam with the Era 100’s greatly widens the soundstage. Sounds good. 
• TV audio:  Grouping the Era 100’s to the Beam for TV is okay but not really needed. For me, dialog is actually a bit clearer without the Eras. And of course, grouping doesn’t provide the benefits of surround for movies.

Based on the info you provided, it seems I should be able to (1) add the Eras as surrounds for TV and (2) having the Beam and Eras always zoned together should work just as well as grouping for streaming music—as long as Music Playback setting is set to FULL . I’ll give it a try!

Update: So far so good. My new Living Room zone with Beam + 2 Era 100’s is working for music streaming and TV. Two things remain:

• Finding some content to watch that really makes use of surround. I can hear sound coming from the Era 100’s, but it’s kind of lost in the background. Nothing like isolated 3D spatial audio. Will this require messing with Dolby Atmos or is this setup ready to go and I just need to find the right content? Obviously, I need to do some more reading on this topic…
• When sitting in the dining area behind my sofa and streaming music, the left Era 100 is slightly closer. I’m trying to find a way to adjust balance like you can do with a stereo pair. Is that even possible when the Eras are slaved to the Beam?

Under your Room and Surround Audio you can adjust the distance if you aren’t using TruePlay.

Folks have recommended good Atmos content around here, search for Atmos and you should get a start.

Just saw this suggestion in another topic by jgatie :

As a definitive test, play an action movie.  There's good use of surrounds in the opening scene of Saving Private Ryan.  If that's too intense, try the battles scenes in the first Avengers movie.

Thanks for the tips!   

I did notice the Surround Audio distance setting under my new Living Room zone. But my impression was that’s for surround audio from the TV which is nearly perfect when sitting on the sofa.

The location where Era 100 distances are slightly skewed is at my standing desk in the dining room. Left Era is 3.4 ft. while right is 5.6 ft. Then, I also noticed surround distance is not as fine-grained as stereo pair balance. Available settings are “Less than 2 feet”, “2 to 10 feet”, and “More than 10 feet”. 

Since both speakers are already within the middle range, it seems I’ll have to play around with physical speaker placement. Where there’s a will, there a way!