simplyderp :
What happens when you play a movie's 5.1 sound source on 2.1 speakers? Will the sound from the 3 removed channels be truncated or added to the 2 channels left? Will it be EXACTLY the same as playing a 2.1 sound source from the same movie?
Like welshmousepk said, it depends on your setup. It also depends on your source and on you. Some DVDs have more than one audio scheme recorded on them, and you can go into the disc menu and select 2.1, or stereo. If my receiver, for example, gets a stereo signal, it will split out the low frequencies on its own in initiative, effectively making 2.1 out of stereo. I believe that this is normal behavior for a modern receiver. Some DVD players will downmix before sending the signal to the...