The rear speaker on my '68 is missing and looking for a replacement i see that most if not all are set up for a two wire hookup. Mine has the single blue wire (from the fader control) that will run to the speaker. Ames used to have a 6x9 with a pigtail that adapted it to a single wire, but it is discontinued. Any one have a suggestion on how to wire the single wire to a two prong speaker, or know of a pigtail that adapts? Thanks.