Not to take sides here, but its worth mentioning that current is drawn, not forced as the gasoline hose analogy would imply. All that is required is a cable with sufficiently low resistance that is able to provide the current when demanded. If 18 gauge doesn't adequately fit this bill, then a larger cable will likely be a benefit. However, the amount of current demanded by a DVD player is relatively small, and a 6 foot run of either 18 or 12 gauge copper wire should have very low resistance, so its likely that any differences you hear are probably due some factor other than the ability to carry current. I know that there are many theories about producing high quality power cables, and its possible that something is coming into play other than the absolute size of the wire.
Cheers,
Ken
Cheers,
Ken