I actually just sold my arcam avr21, I was running a 7.1.6 setup. I had an arcam avr10 that I sent In for the hdmi 2.1 upgrade that I was using in my office. Decided to try 7.1.4 using this avr10 and could hear no difference after testing for over a week. Sold arcam a few days ago to replace all the money I’ve been spending on this hobby.
I’ve actually been selling a lot of gear that I don’t need anymore or use enough. The four avrs in my house are arcam avr10 with revel f208, c208, two Rythmik fv18pc, nad t977 amp in a 7.2.4 configuration. Second setup is a marantz 6015 with canton vento 896 and 866 center in a 3.0 configuration. Third is a denon 4700 with Jbl l890, infinity beta c360, 4 infinity beta 20 and two energy exl12 subs in a 7.2 configuration. Lastly is a denon 3300 with infinity beta 50 and beta c250 in 3.0 configuration. You can see I like harman!
I mentioned all that because I’ve swapped avrs around to see which I prefer in each system. Spending weeks with each unit and I can say without a doubt they all sound a little different at the beginning. With proper setup and eq I can get them all to sound just as good as any of them. Really the speakers determine the most, or the room itself. It can only sound as good as the speakers can play. My revel 208 sound just as good on the marantz 6015 as the arcam avr21 did. If you like playing things loud get the right speakers with great subs and plenty of power. If you don’t crank it up buy great speakers and don’t worry about power, something like denon 3700 would be great.
If you’re building a big theater the arcam 21 can process up to 16 channels. So 7.3.6 is really what I did, but they have many configurations. Avr21 isn’t hard to find at a discount from dealers, but will still run around $3500-4000. Don’t pay retail at Best Buy magnolia, $4700 plus tax is crazy. I got $3000 for mine, which I was ok with.
also what speakers are you running? If you’re investing that much in an avr you must have nicer speakers.