sonos amp and in ceiling speakers

Hi! I have an Arc, a Sub and two Ones in my tv room. I would like to add ceiling speakers with an Amp. I have a couple questions and wonder if y’all could help?

1. Will the Amp and ceiling speakers be a part of or add to the Dolby Atmos provided by my current system?

No, the Amp cannot be ‘bonded’ with your current setup. but it can be ‘grouped’ which is fine for stereo playback of music audio, but you may (likely) experience a delay/echo for TV audio which would be stereo-output too (from Amp speakers) in a grouped-room setup. You can however ‘swap’ the Amp for your rear ‘One’ surrounds if you prefer (you just can’t have both).

1. I want to install the Amp in the attic next to my router. Can I connect the Amp with an ethernet cable and still use all the Atmos  and surround sound benefits? This way I would be able to do all the wiring without messing with speaker wires in walls. All wires would be routed in the attic space.

You can wire the Amp to the network, but see my reply above. Also if you did want to swap the Amp for the Ones the Amp ideally needs to speak direct to the Arc and not have to go via the router so you might find it better to put the Amp in the same room as the Arc and let it connect to the main player over a 5Ghz ad-hoc connection instead.

1. How effective would the ceiling speakers be if not sitting directly under them?

Quite effective, but moreso for general music audio rather than TV audio IMHO - I think you are better off using the ‘Ones’ for TV HT surround sound.

1. And finally, at app $1300, will the addition of ceiling speakers be worth it? I know it is subjective, but $1300 should provide a noticeable improvement!

I would not waste the speakers but use them with the Amp as a separate Sonos ‘Room’ but mainly for music audio purposes. That would be my chosen arrangement. I’m not a fan of TV (rear) surround audio coming from above, but YMMV.