How far are you seated from the Arc? How far will you be seated from the surrounds? How tall is your ceiling? Is it flat and without obstructions? Do you watch or listen to much Dolby Atmos content?

i think im about 10 from tv…. ceilings i also think are 10 feet… i watch netflix and other streaming services, im not sure if they have dolby atmos content.

i was thinking of putting the fives or 300s in the red areas, is that too far back?

@Garland

Imho as Rearspeakers they would be much too far away. I think the best solution would be what you don‘t like to have… a pair of Era 300 with floorstands left and right near behind your sofa. 
I really don’t see another good position to place a pair of rearspeakers. 

ty… u would think that true play would detect my seating area and therefore have the rear speakers increase their volume…. does that make sense?

My other question, how do i properly do true play?

Do i just walk around my couch?…. or do i walk around the whole room close to the wall? 

Do i only make sure to make one full circle when doing true play?

Ive tried both and idk if i can tell a difference, my ear is not that good i guess.

@Garland

I think trueplay can do a lot but if you place two rearspeakers at the red marked positions even trueplay can’t optimize that. Imho the distance ist too large to get effect sounds like they should be. But if you like you can try it. Maybe you will like the result… sound is a very subjective impression. 
For home cinema products trueplay setting is split into two rounds. The first one for optimizing tv sound you just have to sit at your usual tv watching position holding the Apple device in front of your eyes. 
After this there is a second round for optimizing music where you have to move in the whole room moving the device up and down as shown in the trueplay intro video. 

idk if this is a dumb question but how is it when i go to the movie theater we dont have rear speakers right behind us and it sounds great but at home we must have rear speakers right behind us?… why cant we duplicate the same thing at home?

I haven’t been at a modern Atmos equipped movie theater for a long time, but if i remember correctly these theaters ARE equipped with dedicated speakers for all channels including direct firing speakers from the ceiling, side rearspeakers and back rearspeakers. You mostly just can’t see them, because they are covered. 

The Era 300s are atmos capable speakers that fire audio primarily from the sides and top when used for surround speakers.  So placing them ~10 feet back of the seating area is pretty much useless at any volume. You may hear them from your seating area, but you will have lost the effect of having audio coming from the proper direction (bounced off walls and ceilings).

If you went with a ‘standard’ speaker, you can place them that far back and adjust by turning up the volume.  It’s not ideal, and audio will be very loud in your back area, but you can do it.   I wouldn’t spend money on Fives though, the new Era 100s should be plenty good enough for surround duty at half the cost.  I would also place the speaker near fridge on the other side of the stove.  It’s a better angle at that distance with less interference.

That said, you definitely are better off with rear speakers closer.  I get that you don’t want use stands, or a sofa table behind the sofa, perhaps due to lack of a near by electrical outlet.  Is there an outlet on the pillar?

As far as movie theatre sound and why it ‘works’.  First, they don’t bounce any audio off walls.  All the speakers are in walls and ceiling directly pointed at the audience.  Second, the speakers are above the seating area pointed down, so the seats near a speaker won’t be overpowered by the volume, but won’t hear as much coming from that audio channel.  Third, there definitely is a sweet spot in theatres where you’re going to hear the audio the best, as it’s intended.  If you sit on the edges, you likely are not getting the best sound and may not even be hearing some of the audio.  When setting up a home theatre, you want the sweet spot to be where you typically are going to sit.

I do have an outlet on the pillar, I’ll upload more photos or if I can video of my current set up… I connected my second subwoofer and I didn’t get that boom that I expected, I had to increase the bass to get it, maybe it’s the placement where I put it.

From the tv to the other wall where the refrigerator is was close to 30 feet, I measured it.