Parents just remodeled there house. I told my parents and showed them where to have the contractor run the wiring. As usual my father half listens. I told them to run a sub cable through the walls just in case they want to add a sub. Well, instead of a sub cable he had him run a speaker wire. We don't have access to take it out or rewire bcause its cathedral ceilings and no longer have access to the attic. Is it possible to convert this speaker wire to a sub cable?