why are there so many??? they have so many different frequencies etc... how the hell does th eaverage joe even know what these options are, let alone if my AVR will process them...??

should i just check every one? thats how i had it before, but for no real reason i went in and unselected anything that was 7.1 as i have a 5.1 setup... now i'm wondering if this will limit things.

ie:if a BD has the option of 7.1 DTS or 5.1 DD, then arent i better to have it come in as 7.1 dts and have my AVR scale that to 5.1 DTS opposed to just 5.1 DD coming in?