Dave_M
Agent
OK, after pulling my hair out and reading an endless thread over at AVS forum, I got an answer to my question. You must choose either 2 Large or 2 Small for surround back speaker setup in order to get all of the processing options on both THX and Standard. If you choose only 1 back speaker(like I did), many of the options are "greyed out". I can now get THX Select 2, THX Game, and THX Music to work in addition to Dpl IIx Movie, Music, and DD EX/DTS ES. All can be used over incoming 5.1/6.1 sources. Also, to me they are much more valuable than the Yamaha processing modes. Right now I do have only 1 back surround but will change that soon. For now, I guess I'm "tricking" the receiver. Wish I could have found this in the manual!