I hope your experience with GIK was as good as mine. Solid company IMO.
Here's a laundry list of things I did with my system -- yeah, I made every one of these mistakes.
Guessing you have already done some or all of the things listed below but… just in case. (Also guessing others will have ideas to contribute.)
There's a big caveat that goes with this. While these worked in my system, YMMV.
Blu Ray Player
- If it is configured with individual speaker distances, set them all to the same distance (say, 12') and turn off any sound correction by the player. The AVR is more capable at this, and doing it twice will only degrade the sound quality.
- If it is capable of doing this, let it pass BitStream instead of PCM for better sound quality. Look for a mode out of the blu-ray player that is digital and let the AVR do the conversion to analog.
- Verify surround speakers are aimed directly at the prime listening position. This helps room correction do a better job.
- Tweak speaker alignment, if necessary. Are they aimed near the prime listening position?
- Find the best location for your sub. There are a few write ups around about how to do this.
- Sub configuration on the sub itself. If your sub has a crossover setting, move it to the highest frequency position. That lets the AVR choose where to do the crossover. Check your sub phase, too. It should be set to where it sounds the loudest. Lastly, if your sub has a crossover on/off switch, turn it off and let the AVR handle this.
- If your AVR supports it, set speaker distances from the prime listening position using a tape measure.
- Calibrate multiple times. Audyssey on my old Integra let me select anywhere from 4 to 8 listening positions. It turned out that 8 positions worked best in my room, with the last listening position on the coffee table. With Anthem's ARC, anything other than 5 positions degrades sound in my room. The key is: experiment, take notes, and use what sounds best. At this point, I have run ARC about 100 times. (Yes, really.) It was a PITA but wow it really sounds great now.
- Experiment with crossover points. I tried values from 60 Hz up to 500 Hz but in the end wound up at 80 Hz.
I originally did these changes when running an Integra DHC-80.2 processor, which had Audyssey XT32, and it helped. Upgrading to the Anthem AVM 60 processor using ARC made an even bigger difference. ARC is amazing. At the end of the day if you still aren't happy with your AVR, you might want to try the MRX 720. Others may disagree but it looks like the best of the group you listed.