No need for the Arc Ultra if you’re not planning to connect it to a TV. 

I would suggest four Era300s - each is capable of playing Dolby Atmos, and you can space them throughout the area. All you need to do is group them in the app and they will all play in sync. (74 sq.m is hard to judge from a plan - maybe two speakers would be enough as they carry quite some punch - but to get into all the area then 3-4 speakers might be best.)

I too would go with Era 300’s. A single 300 can play in stereo/Atmos, or two can be stereo-paired. I would stick with single speakers, grouped to play the same source. I suspect 4 speakers (or more) would be best, to avoid having loud/quiet zones in the space. 

I think it should be said that atmos music really isn’t a good fit for a waiting room space.  The point of atmos is so that the audio appears to be coming at a designated listening area from multiple directions creating an immersive effect.  When you are outside of the listening area, the audio doesn’t sound nearly as good, worse than a stereo signal in my opinion.  In a waiting room, you’re likely to have a lot of people outside the listening room, not to mention that the volume will likely be rather low and difficult to appreciate the immersive effects.

You can certainly still get Era 300s and test it out.  You can set the Era 3000s to play stereo only if you find that it meets your needs better.

I agree with the above.  No need for a soundbar, and not sure Atmos is applicable to a room that large.  However, I do see that Apple Music has nature soundscape tracks in Atmos Audio, so it would be worth a try.

https://music.apple.com/ca/playlist/nature-soundscapes-in-3d-spatial-audio/pl.c5ff2acd89d947579030e99078e291db

>Rhonny

thank you for teaching me. I see that Arc Ultra isn't necessary, now I understand. Because it's a clinic's waiting room, there's no need for powerful sounds; I wanted to express the chirping of birds in the forest and the murmuring of a river at a low volume. In that case, would it be better to have more than four speakers?

>nik9669a

thank you for teaching me. I guess Era300 is the best choice after all. I guess the idea is to group all four units together and play Dolby Atmos spatial audio sources on each? Would this space be enough for four? Since it's a clinic, they can't make that much noise.

>melvimbe

Thank you for a very important point. I understand that Dolby Atmos is vulnerable when outside the listening area. As you say, the volume must be set low in the waiting room. In this situation, would it be important to increase the number of ERA 300 units to expand the listening area?

It's true that there may not be any need to be so particular about Dolby Atmos. However, we are exploring ways to stimulate the senses and provide a more relaxing experience than a traditional clinic.

They will play as high or as low as you want.  Personally, I would put one in each corner of the lower wall, and two more on the upper wall at the 1/3/ and 2/3 mark.  Each should be one room, then grouped together.  Also, you can set a volume limit so nobody accidently raises the volume above the level you wish. 

>jgatie

Thank you for the valuable information. Apple Music has a really large selection of natural forest sounds. If it's natural sounds, I'd definitely like to try the Dolby Atmos environment. To make atmos suitable for a large room, would the solution be to increase the number of speakers at low volumes? Please let me know if you know anything.

Not necessarily.  Each single speaker will be making a “dome” of atmos effects, and you want to keep those from overlapping.  I’m not sure how spread out the atmos dome is for a single speaker, but I’d start with 4 in the layout I gave and see if it is satisfactory.  Again, the room is not ideal for Atmos, so expectations should be tempered a bit.

Dolby Atmos is best for one seating position with Atmos speakers in front and slightly behind (left and right) - e.g. in a home theatre setup. It is not meant for wide open spaces where sound will bounce randomly off walls - you will simply lose the effect. Animal/nature sounds through the Era300s will sound great whether the tracks are in Dolby Atmos or stereo. I wouldn’t focus too much on the Dolby Atmos part. Multiple speakers positioned evenly around the space, playing low natural sounds, will produce a good calming effect - the clients/patients won’t know or care if it’s Atmos or not in that space.

I would consider a Sonos Amp, set to mono sound, and six Sonos/Sonance in ceiling speakers, that greatly reduces the complexity of your system. In wall speakers are also a possibility but it would usually take more of them to have as even a sound level across the room.

Evenly distribute the speakers along the centerline of the ceiling for the most even sound levels. If you are concerned it won't be even enough sound you could use two Amps and up to 12 speakers but that would be many more than I'd expect to be needed.

>jgatie

Thank you again for your very practical opinion. It is very easy for me to understand that atmos should be imagined as a dome. So my question is, if I were to take four Sonos speakers, group them together, and use the "TruePlay" function, would it be possible to enlarge the Atmos dome and achieve the appropriate sound field expression? Maybe I'm too obsessed with Dolby Atmos. As you say, I have to keep my expectations modest.

No.  Groups cannot be Trueplayed, and each single speaker (or stereo pairs) would be independent from any other.

>Rhonny

What you say is so true. I'm sure the patients don't care at all whether they have atmos or not. It may just be my own self-satisfaction. If I put a sonos speaker in my clinic, I can try out atmos and stereo, and I might just use the one that feels more comfortable.

>Stanley_4

Thank you for presenting a new solution. However, I would like to put aside the discussion so far and ask a question. Is it possible to create an optimal atmos environment for this 750 square feet waiting room using several Era 300s and the accessory Sonos Era 300 Wall Mount? I fully understand that it is difficult, but I would like to challenge a new type of clinic, a waiting room that can provide an enveloping music experience. I would appreciate it if you could let me know. Thank you in advance.

Forget ATMOS for this application. Trueplay will have marginal benefits because it also attempts to optimize for a single listening position.

I recommend installing multiple speakers, such that a given listener is no more than 10-15ft from a speaker. Alternate left and right around the room such that each listener is likely between a left and right speaker, regardless of location in the room. This will result in an even ambience throughout the room, without creating hot spots.

Hiring a pro would be a good idea. A multi-channel amplifier and a SONOS PORT would be a good basis for this application. It could easily integrate with a larger SONOS system without a lot of operational fuss. Consider operating at a lower Volume in the reception desk area. The pro can easily accommodate this.

Pendant speakers might be an attractive option in this application.

​@Futchy 

Given you are wanting to achieve absolute perfection then, as ​@buzz said, hiring a professional would be a good idea. If you absolutely must have the nature sounds as if you and your patients are there in the jungle/wilderness, then get someone in to deliver it for you. Perhaps even someone who sets up cinema sound.

The best you will achieve with Sonos Era 300s has already been detailed to you a few times.

I think you have a misunderstanding of the Atmos system. I'll try a comparison to see if it helps.

Mono, even sound but no positioning information.

Stereo, not so even sound outside the "sweet spot" but in it you get left-right positioning information.

Surround, 5.1 and similar, even more uneven sound outside the "sweet spot" but it is often larger than the Stereo spot. You get left-right and front-back positioning in the spot.

Atmos, the artist has somthing like 30 channels of sound that can be set to come from a specific point in the listening space, the equipment then does the best it can to map the artist's space into the room and the source channels into the number and position of the speakers. I do not have extensive experience with Atmos listening but I feel the "sweet spot" is less defined and while off spot sound levels are not equal the overall experience degrades less than non-Atmos sound.

What you want would require an Atmos system with multiple speakers BUT they could not be individual or in smaller sets than all of them. Your Atmos amplifier would need to map each speaker into the room and assign the artist's channels to each. That would create the "bubble" you are looking for but there would still be a sweet spot and outside of it the sound would be uneven.