If you’re running the HDMI out from your Fios box to the Marantz and then HDMI from the Marantz to your TV it should be fine. I suspect you need to change some settings in both the Marantz and TV to get things looking and sounding better. Also check your Fios cable box settings to make sure it’s sending out the highest quality signal. If none of that works maybe you have a faulty or poor HDMI cable. In any event, if you have a good TV and audio system things should be looking/sounding pretty good with what you have. I’m only addressing the cable TV issue (not the PS4 streaming) to make sure that’s working right first.
how to set up good home theater sound (and picture)
I am very new to the latest home theater formats. I have a new 4k TV but I don't yet have any devices that will stream 4K. My fios box does TV and I do netflix, amazon, and disney through our PS4. I just got a Marantz AV 7702 processor. I used to run Theta digital equipment for DVDs but no one buys disc players anymore, right (even 4k disc players)? Oppo seems to have gone out of business. Is the new PS5 an audiophile quality player? Will a new FIOS box satisfy? I'm wondering why I even have a good processor but I definitely miss good quality sound for movies. It's only OK running the current equipment into the Marantz and nowhere near what I remember from a Theta DVD player and my old Sunfire processor. It should be much better with the new sound formats. One option for video would be to run the apps directly from the TV, which would optimize video, but then I'm running an HDMI cable from the TV to the Marantz, and I assume that would be poor sound quality? How do you get audiophile quality movie sound these days? Thanks all.