A:AnswerFrom what I know the speakers on 3920 are better they have 2 separate speakers a subwoofer and a tweeter per satellite. The 4920 have a single cone speaker per satellite.
A:AnswerOf course you can turn the system off, while still watching tv. That thought never even crossed my mind. All you have to do is buy a 4 way channel and wire it to the amp on the left speaker. Then boom it's still using 750 watts
A:AnswerWhat country you're buying it from will determine the voltage standard.
110v/120v is standard U.S. voltage.
220v is standard for Europe and parts of Asia.
This site might assist you better.
http://www.controlledpwr.com/help-international-voltages.php
