Do I need Air Play for my ARC, AMP and SUB

Why do you need to use AirPlay, rather than setting up your current library to allow access to the data? I currently have both, but honestly, greater than 99% of the time, I use Sonos’ software, rather than Apple’s and AirPlay 2. 

I have a wide mix of devices, all running S2, including PLAY:1s and PLAY:3s. If I have ever needed to send AirPlay 2 to a device that normally isn’t a receiver of it, I just send the AirPlay 2 to a speaker that can receive the signal, and then, using the Sonos controller (app), just group that speaker with those I want to get the signal to. 

Not sure how you tried adding it. Did you follow the instructions at the FAQ? Where is your library located? Have you called Sonos Support to discuss it?

When you speak directly to the Support staff (not the chatbot), they have tools at their disposal that will allow them to give you advice specific to your network and Sonos system.

AirPlay is standard on all Sonos devices made since 2019 at least. So your question “but I don’t know if I need to have AirPlay on my ARC, AMP and SUB” seems strange to me; AirPlay is already there for you to use if you want it. Besides that - since the Sub is always part of a Sonos room, it cannot be Airplayed to on it’s own.

Regarding your older gear. That can be grouped with the speaker you AirPlay to, so if that is convenient for you, you would not need to replace it.

All my Sonos stuff is pre 2019, except for an ERA100.  My issue is the Sonos desktop app won't allow me to play from my iTunes Library (without paying for Apple Music).  With Air Play I can play from my Library (to my one ERA100).  So I’m getting new ERA 100’s but wasn’t sure if I needed to get a new ARC (ARC Ultra).  Tried to follow the instructions to make my Library a shared folder (which i did and it now sits on my desktop) but can’t seem to add the shared folder to Sonos.  Tried working with tech support but could only get their AI and we just went around and around in a loop never solved anything.

Just so you know if you are using the Era 100’s as surrounds (or any Sonos speakers used as a surround even though they are AirPlay capable) you cannot AirPlay to them directly. Music sent to the Soundbar to which the surrounds are bonded can be heard through the surrounds as is the case when sending any music to the soundbar.

I semi frequently use AirPlay 2 to send some content (most often iHeart radio, but could be anything) to my Era 100s. I then group that Era 100 with my ‘earlier’ speakers, which don’t show up in the AirPlay 2 menu, using the Sonos controller. That way, I’m able to get my AirPlay 2 signal to speakers that aren’t showing up in the AirPlay 2 menu.

For what it’s worth, I have my iTunes library (which happens, at the moment, to reside on an NAS, but could easily be a Mac hard drive) shared with Sonos, by following the instructions that Sonos has for adding library access. Note that Sonos itself doesn’t ’maintain’ its own library, just access to other ones, like Apple’s, and others.

There should be no need, if you want to continue to use AirPlay 2 to your Era 100, to replace any of your earlier speakers. You’d just group it with your ‘older’ speakers, and get the AirPlay 2 content out of the Era 100 and any other grouped room at the same time. 

Note this is for music, not for TV audio, there are restrictions in sending a TV signal (from any Apple device) to a Sonos. 

Also, I’m not sure Sonos has any idea whether a ‘folder’ that contains music is ‘shared’ or not, that isn’t the way that Sonos accesses music data. Sonos works by reading data directly, not by going through the operating system’s functionality.