I would suggest some research about the 4k over at
AVS its not really 4k. I have read about it but cant really explain it and really its way off in the future unless you have deep pockets. The room correction helps in rooms that are not properly treated for acoustics. Audyssey is considered the best of the lot in a receiver the average guy can afford.
This Video is a good primer by Joe Kane about 4k. You will probly find yourself ending up wanting something in the 1k range, so if you have a budget of 500.00 keep you sites on the midrange recievers and don't get to worried about audyssey its overhyped in my opinion.
