You can join your 12 gauge wire with a short strip of 14 gauge wire using a wire nut. Electricians use them in homes to join wires together in electrical junction boxes. Make sure that you choose the wire nut color that is designed for joining one 12 gauge wire to one 14 gauge wire. Each color represents different wire size combinations.
Volume Controls that Accept 12 Guage??
I broke down and am buying in-wall speakers for background music driven from my main amp (maybe a new one?) for areas of the house away from my main set-up. After doing some research, I went with 12 gauge KimberKable as the wiring. Whoops!! Despite some serious research on my part I can't find in-wall volume controls that handle anything larger than 14 gauge wire. Oh the humanity !!! That seems to be a bit self defeating but I already spent the money on the wire and had it installed. Please let me save some face here. Anyone know of volume controls that would work??