I have a 5.1 surround system. Won't bore you with the component details unless it becomes important to know. For ANY DVDs I have with the THX Optimizer menu: the test tones come out of all the channels (L, R, C, SL, SR) except the sub. Receiver Xover set @ 80Hz and volume is raised during the test. When I play the movie, I get sound out of the sub at expected levels. Can anyone tell me why? I guess everything seems to work ok but simple curiosity demands an answer why the sub test is silent.
So you are saying with the same disc, sub power on and without changing any settings or connections that you don't have sub output during the Optimizer but you do when you play the movie?
I have no ready answer for you but you definitely have my attention! This sort of curiosity will be the death of me (us?) as there is no obvious answer but I do plan to spend some time with a disc that has the THX Optimizer just to see if I can recreate this oddity.