Basically, movies and TV shows mix together multiple recordings, including dialogue, sound effects, music, etc. But achieving the right balance of all those elements is a problem when you’re trying to create something that works on different home theater systems. The sound for these shows is often mixed for surround sound systems, which most people don’t have. “So all the various audio channels play through only a pair of speakers instead of a whole array of them,” How to Geek writes.