As Robb said, conduit is not necessary.
If sound-proofing is such an issue for you, consider building a "room within a room". Aside from that, use 5/8" drywall instead of a half inch and try to get the largest sheets possible to minimize joints. Screw and glue the drywall wherever possible. Use weatherstripping on all doors to prevent them from rattling. Staggered studs also help a lot to provide further isolation. I also used Roxul Safe n' Sound in the ceiling joists with a 2" airspace to act as a baffle. And the less vents for noise to travel the better. I eliminated all vents and decided to heat the A/V room with a direct vent fireplace.
