My Gen 2 Sub connected without problem.

If you factory Reset just the Sub can you add it as a new device to your existing system?

You can see what the App thinks about connections under settings.

I bought it new and out of the box the app could not find it. Oh well. I returned it. Crazy to surrender that much and it did not work out of the box. Never has issues setting up wired systems. At least the arc ultra is working great.

I have not personally connected the arc ultra to the GEN three sub but I have spent like eight hours connecting in different iterations yesterday and I figured some stuff out. To connect it you’re going to want to do the following
 

— before you begin delete any subs in the group, Or if it says delete but the sub is not there then go ahead and do it anyway—
- First of all you’re going to want to go to the manage networks and you’re going to want to delete your network(this is located to the right of the groups click the button that says manage). Next you are going to want to go to your account and go to App preferences, And under product Set up go ahead and enable Multi product set up. So you will have your ultra selected and that is all. Go ahead now and Prepare the other device for pairing. — You can do it first within the group and then if that is unsuccessful then do it outside of the group and click the button that says add speaker or component. When you have to re-enter your network you will do that except you will do that one time and then it will all be nice and you will now be synced you’re welcome

​@Zendawn8008 I’m not sure al you mention should be necessary, but if it worked for you, it could help other people too. Just to make sure, where you mention “group”, do you mean “room”. A room is a speaker or a defined stereo or surround set of speakers. Rooms can be “grouped”.