surround processor?

2 speaker and home theater are entirely different. You listen differently. HT is a visual experience with potentially a great immersive sound. I don’t listen to my Marantz 11.2 system for the accuracy of the gun shot sound. I do listen to my 2 speaker pass labs system for the accuracy of the piano. HT subs should literally shake you. 2 speaker setups should have subs that extend and melt into the sounds of your front speakers. My surround sound speakers don’t begin to match the quality of my 2 speakers. And they don’t have to. Having a creepy sound behind you doesn’t have to come out of $20k speakers. I love both setups. But HT and 2 speaker are mostly different systems because we listen differently to each setup. To answer your question, I bought the Marantz many years ago because of the 13 channels and the auro 3D. It’s modestly priced and works well. 

Make sure what you get will do at least 4K video, the Classe mentioned above does not.

Make sure what you get will do at least 4K video

Absolutely. Clarity of sound and clarity of image are the way to go. Substandard surround speakers are like a substandard center speaker; not recommended for those who appreciate quality.

Two channel needs its own dedicated system. There are many here that claim to have found the holy grail of doing 7-1, 8-1 and 2 channel from the same system. If they are happy with their system and the sound it is not my place to question them. I know from my personal quest it is different. I went into hibernation for 10 years on audio file 2 channel. Dove head first into surround sound ( current is 9-2). The in home experience watching a movie is fantastic and love it. I played cd’s through the dvd player, watched concerts and they all sounded really good to my ears. Then I got the itch to put my tt back into play and started listening. The more I listened the more I felt something was missing. I stopped by an old friends home and he has a great 2 channel system. It only took the first song for me to realize the injustice my system was doing to 2 channel. Left his home and started the journey of dedicated 2 channel and have never looked back. In summary my left side cabinet is surround and my right side cabinet is 2 channel. My wife hates it but as more time has passed I don’t even hear her any more. She is like the teacher for the peanuts! At the end of the day only one thing matters. Enjoy the music!

Agree with Vinylshadow on the Classe SSP 800.  The Classe Sigma SSP, that I have, was a newer, and less expensive model when it came out. However, it also has a great DAC for 2 channel.  The SSP 800 is a better choice if you prioritize multi channel as all channels are fully balanced, while the Sigma is only fully balanced for 2 channel.