I have had my Yamaha RX-V800 for about 10 years and I have yet to figure ou how to optimize the Parameter Settings for any particular input source. I tried today with the Movie Theater inputs (the ones I am most interested in setting) , but as usual, I drove myself a bit daffy trying to "hear" the differences as I manipulated the individual parameters. Also, I really didn't think I understood what I was doing. Perhaps if I give you an idea about the room's characteristics and my seating postion, you may be able to give me some clues on how to approach my lingering 10-year problem. BTW, if I am in the wrong place to ask this question, please direct me to the right one(s). I sit about 10-12' from the three front spkrs and about 5.5' from the rears on either side of me. There is a plasterboard wall right behind me and the front spkrs are built into an entertainment center; it's about 13' from the face of the entertainment center to the wall behind me. About 7' to my left is a wall that is mostly sliding glass door, and to my right it is essentially open leading to the dinning room and foyer areas...in other words, no immediate wall to my right. The ceiling is high, thw floor is tile, and about the only thing that would absorb sound would be the 12' cloth sofa I sit on. The movie parameters are: P Init Delay, Room Size, S. Delay, S.init Delay, S. Room Size. See page 61-63 in the User manual for details (http://www.usersmanualguide.com/yamaha_audio/av_receivers/rx-v800). Certainly, if someone could give me some starting paramters and what to look for in the way of sound differences that would be great. But, if I also got some reasoning why these changes are made, that would be the best as this would enable me to rationally make changes...if needed.