If I’m making a movie that has 5.1 ac3 audio, do I still need to include a 2channel strereo track when authoring the movie? In other words, can I just use the 5.1 track to play on surround sound systems as well as 2 Channel setups? Or do I need a seperate 2ch track as well?
5.1 can be played on most 2 channel systems using a technique called downmix which should be present on either the Player or the Speaker Amp set-up. So rolling56 is correct.
Hope this helps.