Hello. I recently picked up a set of 816C cabinets that are loaded with ER 15 speakers, and have N1209-8A croosvers with 511b series horns with 908-8b drivers mounted to the top of them. They sound amazing, but I haven't been able to find any info on the ER 15. Is it a good driver? Does anyone know the specs? Also does anyone have an idea of what these are worth? They are in exceptional condition. As good as they sound, they are really bigger than I have room for. Thanks